SPOT(1)

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Spot
Spot is a powerful and easy-to-use tool for effortless deployment and configuration management. It allows users to define a playbook with a list of tasks and targets, where each task consists of a series of commands that can be executed on remote hosts concurrently. Spot supports running scripts, copying files, syncing directories, and deleting files or directories, as well as custom inventory files or inventory URLs.

  Getting Started

•   Install Spot by download the latest release from the Releases (https://github.com/umputun/spot/releases) page.

•   Create a configuration file, as shown in the example below, and save it as spot.yml.

•   Run Spot using the following command: spot. This will execute all the tasks defined in the default spot.yml file for the default target with a concurrency of 1.

•   To execute a specific task, use the --task flag: spot --task=deploy-things. This will execute only the deploy-things task.

•   To execute a specific task for a specific target, use the --task and --target flags: spot --task=deploy-things --target=prod. This will execute only the deploy-things task for the prod target.

Install from homebrew (macOS)

        brew tap umputun/apps
        brew install umputun/apps/spot

This will install both spot and spot-secrets binaries.

Install from deb package (Ubuntu/Debian)

1.  Download the latest version of the package by running: wget https://github.com/umputun/spot/releases/download/<versiom>/spot_<version>_linux_<arch>.deb (replace <version> and <arch> with the actual values).

2.  Install the package by running: sudo dpkg -i spot_<version>_linux_<arch>.deb

Example for the version 0.14.6 and amd64 architecture:

        wget https://github.com/umputun/spot/releases/download/v0.14.6/spot_v0.14.6_linux_<arch>.deb
        sudo dpkg -i spot_v0.14.6_linux_<arch>.deb

Install from rpm package (CentOS/RHEL/Fedora/AWS Linux)

        wget https://github.com/umputun/spot/releases/download/v<version>/spot_v<version>_linux_<arch>.rpm
        sudo rpm -i spot_v<version>_linux_<arch>.rpm

Install from apk package (Alpine)

        wget https://github.com/umputun/spot/releases/download/<versiom>/spot_<version>_linux_<arch>.apk
        sudo apk add spot_<version>_linux_<arch>.apk

Universal installation for Linux and macOS

Spot provides a universal installation script that can be used to install the latest version of the tool on Linux and macOS.

1.  Download the installation script: wget https://raw.githubusercontent.com/umputun/spot/master/install.sh

2.  Carefully review the script to make sure it is safe.

3.  Run the script: sudo sh install.sh

The script will detect the OS and architecture and download the correct binary for the latest version of Spot.

If you are brave enough, you can run the script directly from the web, but I'd recommend downloading it first and reviewing it:

        curl -sSfL https://raw.githubusercontent.com/umputun/spot/master/install.sh | sudo sh

Install with go install

This method requires Go (https://golang.org/) to be installed on your system.

        go install github.com/umputun/spot/cmd/spot@latest
        go install github.com/umputun/spot/cmd/spot-secrets@latest

  Options
Spot supports the following command-line options:

•   -p, --playbook=: Specifies the playbook file for use. Defaults to spot.yml. You can also set the environment variable $SPOT_PLAYBOOK to define the playbook file path.

•   -n, --task=: Specifies task names to execute. The task should be defined in the playbook file. Several tasks can be executed by providing the --task flag multiple times, e.g., -n copy_files -n warmup_cache. If not specified all the tasks will be executed.

•   -t, --target=: Specifies the target name to use for the task execution. The target should be defined in the playbook file and can represent remote hosts, inventory files, or inventory URLs. If not specified, the default target will be used. User can pass a hostname, group name, tag or IP instead of the target name for a quick override. Providing the -t, --target flag multiple times with different targets sets multiple destination targets or multiple hosts, e.g., -t prod -t dev or -t example1.com -t example2.com.

•   -c, --concurrent=: Sets the number of concurrent hosts to execute tasks. Defaults to 1, which means hosts will be handled sequentially.

•   --timeout: Sets the SSH timeout. Defaults to 30s. User can also set the environment variable $SPOT_TIMEOUT to define the SSH timeout.

•   --ssh-agent: Enables using the SSH agent for authentication. Defaults to false. Users can also set the environment variable SPOT_SSH_AGENT to define the value.

•   --forward-ssh-agent: Enables forwarding of connections from an authentication agent. Defaults to false. Users can also set the environment variable SPOT_FORWARD_SSH_AGENT to define the value.

•   --shell - shell for remote ssh execution, default is /bin/sh. Users can also set the environment variable SPOT_SHELL to define the value.

•   --local-shell - shell for local execution, default is os shell. Users can also set the environment variable SPOT_LOCAL_SHELL to define the value.

•   --temp - temporary directory for remote execution, default is /tmp. Users can also set the environment variable SPOT_TEMP_DIR to define the value.

•   -i, --inventory=: Specifies the inventory file or URL to use for the task execution. Overrides the inventory file defined in the playbook file. Users can also set the environment variable $SPOT_INVENTORY to define the default inventory file path or url.

•   -u, --user=: Specifies the SSH user to use when connecting to remote hosts. Overrides the user defined in the playbook file .

•   -k, --key=: Specifies the SSH key for connecting to remote hosts. Overrides the key defined in the playbook file.

•   -s, --skip=: Skips the specified commands during the task execution. Providing the -s flag multiple times with different command names skips multiple commands.

•   -o, --only=: Runs only the specified commands during the task execution. Providing the -o flag multiple times with different command names runs only multiple commands.

•   -e, --env=: Sets the environment variables to be used during the task execution. Providing the -e flag multiple times with different environment variables sets multiple environment variables, e.g., -e VAR1:VALUE1 -e VAR2:VALUE2. Values could be taken from the OS environment variables as well, e.g., -e VAR1:$ENV_VAR1 or -e VAR1:${ENV_VAR1}.

•   -E, --env-file=: Sets the environment variables from the file to be used during the task execution. The file can have values from the OS environment variables as well. The default is env.yml. Can also be set with the environment variable SPOT_ENV_FILE.

•   --no-color: disable the colorized output. It can also be set with the environment variable SPOT_NO_COLOR.

•   --dry: Enables dry-run mode, which prints out the commands to be executed without actually executing them.

•   -v, --verbose: Enables verbose mode, providing more detailed output and error messages during the task execution. Setting this flag multiple times increases the verbosity level, i.e., -vv.

•   --dbg: Enables debug mode, providing even more detailed output and error messages during the task execution and diagnostic messages.

•   -h --help: Displays the help message, listing all available command-line options.

  Basic Concepts

•   Playbook is a YAML or TOML file that defines a list of tasks to be executed on one or more target hosts. Each task consists of a series of commands that can be executed on the target hosts. Playbooks can be used to automate deployment and configuration management tasks.

•   Task is a named set of commands that can be executed on one or more target hosts. Tasks can be defined in a playbook and executed concurrently on multiple hosts.

•   Command is an action that can be executed on a target host. Spot supports several built-in commands, including copy, sync, delete, script, echo, and wait.

•   Target is a host or group of hosts on which a task can be executed. Targets can be specified directly in a playbook or defined in an inventory file. Spot supports several inventory file formats.

•   Inventory is a list of targets that can be used to define the hosts and groups of hosts on which a task can be executed.

  Playbooks

  Full playbook example

        user: umputun                       # default ssh user. Can be overridden by -u flag or by inventory or host definition
        ssh_key: keys/id_rsa                # ssh key
        ssh_shell: /bin/bash                # shell to use for remote ssh execution, default is /bin/sh
        ssh_temp: /tmp                      # temporary directory for remote execution, default is /tmp
        local_shell: /bin/bash              # shell to use for local execution, default is os shell
        inventory: /etc/spot/inventory.yml  # default inventory file. Can be overridden by --inventory flag
        # list of targets, i.e. hosts, inventory files or inventory URLs
        targets:
          prod:
            hosts: # list of hosts, user, name and port optional.
              - {host: "h1.example.com", user: "user2", name: "h1"}
              - {host: "h2.example.com", port: 2222}
          staging:
            groups: ["dev", "staging"] # list of groups from inventory file
          dev:
            names: ["devbox1", "devbox2"] # list of server names from inventory file
          all-boxes:
            groups: ["all"] # all hosts from all groups from inventory file
        # list of tasks, i.e. commands to execute
        tasks:
          - name: deploy-things
            on_error: "curl -s localhost:8080/error?msg={SPOT_ERROR}" # call hook on error
            commands:
              - name: wait
                script: sleep 5s

              - name: copy configuration
                copy: {"src": "testdata/conf.yml", "dst": "/tmp/conf.yml", "mkdir": true}
              - name: copy other files
                copy:
                  - {"src": "testdata/f1.csv", "dst": "/tmp/things/f1.csv", "recur": true}
                  - {"src": "testdata/f2.csv", "dst": "/tmp/things/f2.csv", "recur": true}
              - name: sync things
                sync: {"src": "testdata", "dst": "/tmp/things"}

              - name: some command
                script: |
                  ls -laR /tmp
                  du -hcs /srv
                  cat /tmp/conf.yml
                  echo all good, 123

              - name: delete things
                delete: {"path": "/tmp/things", "recur": true}

              - name: show content
                script: ls -laR /tmp
          - name: docker
            commands:
              - name: docker pull and start
                script: |
                  docker pull umputun/remark42:latest
                  docker stop remark42 || true
                  docker rm remark42 || true
                  docker run -d --name remark42 -p 8080:8080 umputun/remark42:latest
                env: {FOO: bar, BAR: qux} # set environment variables for the command
              - wait: {cmd: "curl -s localhost:8080/health", timeout: "10s", interval: "1s"} # wait for health check to pass

Alternatively, the playbook can be represented using the TOML format.

  Simplified playbook example
In some cases, the rich syntax of the full playbook is not needed and can feel over-engineered and even overwhelming. For those situations, Spot supports a simplified playbook format, which is easier to read and write, but also more limited in its capabilities.

        user: umputun                       # default ssh user. Can be overridden by -u flag or by inventory or host definition
        ssh_key: keys/id_rsa                # ssh key
        ssh_shell: /bin/bash                # shell to use for remote ssh execution, default is /bin/sh
        ssh_temp: /tmp                      # temporary directory for remote execution, default is /tmp
        local_shell: /bin/bash              # shell to use for local execution, default is os shell
        inventory: /etc/spot/inventory.yml  # default inventory file. Can be overridden by --inventory flag
        targets: ["devbox1", "devbox2", "h1.example.com:2222", "h2.example.com"] # list of host names from inventory and direct host ips
        # the actual list of commands to execute
        task:
          - name: wait
            script: sleep 5s

          - name: copy configuration
            copy: {"src": "testdata/conf.yml", "dst": "/tmp/conf.yml", "mkdir": true}

          - name: copy other files
            copy:
              - {"src": "testdata/f1.csv", "dst": "/tmp/things/f1.csv", "recur": true}
              - {"src": "testdata/f2.csv", "dst": "/tmp/things/f2.csv", "recur": true}

          - name: sync things
            sync: {"src": "testdata", "dst": "/tmp/things"}

          - name: some command
            script: |
              ls -laR /tmp
              du -hcs /srv
              cat /tmp/conf.yml
              echo all good, 123

          - name: delete things
            delete: {"path": "/tmp/things", "recur": true}

          - name: show content
            script: ls -laR /tmp
          - name: docker pull and start
            script: |
              docker pull umputun/remark42:latest
              docker stop remark42 || true
              docker rm remark42 || true
              docker run -d --name remark42 -p 8080:8080 umputun/remark42:latest
            env: {FOO: bar, BAR: qux} # set environment variables for the command

          - wait: {cmd: "curl -s localhost:8080/health", timeout: "10s", interval: "1s"} # wait for health check to pass

For more examples see .examples (https://github.com/umputun/spot/tree/master/.examples) directory.

  Playbook Types
Spot supports two types of playbooks: full and simplified. Both can be represented in either YAML or TOML format. The full playbook is more powerful and flexible but also more verbose and complex. The simplified playbook, on the other hand, is easier to read and write but has more limited capabilities.

Here are the main differences between the two types of playbooks:

•   The full playbook supports multiple target sets, while the simplified playbook only supports a single target set. In other words, the full playbook can execute the same set of commands on multiple environments, with each environment defined as a separate target set. The simplified playbook can execute the same set of commands in just one environment.

•   The full playbook supports multiple tasks, while the simplified playbook only supports a single task. This means that the full playbook can execute multiple sets of commands, whereas the simplified playbook can only execute one set of commands.

•   The full playbook supports various target types, such as hosts, groups, and names, while the simplified playbook only supports a single type, which is a list of names or host addresses. See the Targets section for more details.

•   The simplified playbook does not support task-level on_error field, while the full playbook does. See the Task details section for more information.

•   The full playbook also supports task-level user field, which allows setting the SSH user to use when connecting to remote hosts for the particular task.

•   The simplified playbook also has target field (in addition to targets) that allows setting a single host/name only. This is useful when users want to run the playbook on a single host only. The full playbook does not have this field.

Both types of playbooks support the remaining fields and options.

  Tasks and Commands
Each task consists of a list of commands that will be executed on the remote host(s). The task can also define the following optional fields:

•   on_error: specifies the command to execute on the local host (the one running the spot command) in case of an error. The command can use the {SPOT_ERROR} variable to access the last error message. Example: on_error: "curl -s localhost:8080/error?msg={SPOT_ERROR}"

•   user: specifies the SSH user to use when connecting to remote hosts. Overrides the user defined in the top section of the playbook file for the specified task.

•   targets - list of target names, groups, tags, or host addresses to execute the task on. Command line -t flag can be used to override this field. The targets field may include variables. For more details see Dynamic targets section.

Note: these fields are supported in the full playbook type only

All tasks are executed sequentially on a given host, one after another. If a task fails, the execution of the playbook will stop and the on_error command will be executed on the local host, if defined. Every task has to have name field defined, which is used to identify the task everywhere. Playbook with a missing name field will fail to execute immediately. Duplicate task names are not allowed either.

  Relative paths resolution
Relative path resolution is a frequent issue in systems that involve file references or inclusion. Different systems handle this in various ways. Spot uses a widely-adopted method of resolving relative paths based on the current working directory of the process. This means that if you run Spot from different directories, the way relative paths are resolved will change. In simpler terms, Spot doesn't resolve relative paths according to the location of the playbook file itself.

This approach is intentional to prevent confusion and make it easier to comprehend relative path resolution. Generally, it's a good practice to run Spot from the same directory where the playbook file is located when using relative paths. Alternatively, you can use absolute paths for even better results.

  Command Types
Spot supports the following command types:

  script
Can be any valid shell script. The script will be executed on the remote host(s) using SSH, inside a shell.

        script: |
          ls -laR /tmp
          du -hcs /srv
          cat /tmp/conf.yml
          echo all good, 123

Read more about YAML multiline string formatting on yaml-multiline.info (https://yaml-multiline.info/) and this stackoverflow post (https://stackoverflow.com/questions/3790454/how-do-i-break-a-string-in-yaml-over-multiple-lines) .

  copy
Copies files between the local machine and remote host(s). The optional direction field controls the transfer direction: push (default) uploads files from local to remote, while pull downloads files from remote to local. When direction is not specified, it defaults to push for backward compatibility. If mkdir is set to true the command will create the destination directory if it doesn't exist, the same as mkdir -p in bash. The command also supports glob patterns in src field.

Copy command performs a quick check to see if the file already exists on the destination with the same size and modification time, and skips the copy if it does. This option can be disabled by setting force: true flag. Another option is exclude which allows to specify a list of files to exclude to be copied.

        - name: copy file with mkdir
          copy: {"src": "testdata/conf.yml", "dst": "/tmp/conf.yml", "mkdir": true}
        - name: copy files with glob
          copy: {"src": "testdata/*.csv", "dst": "/tmp/things"}
        - name: copy files with glob and exclude
          copy: {"src": "testdata/*.yml", "dst": "/tmp/things", "exclude": ["conf.dist.yml"]}
        - name: copy files with force flag
          copy: {"src": "testdata/*.csv", "dst": "/tmp/things", "force": true}

Copy also supports list format to copy multiple files at once:

        - name: copy files with glob
          copy:
            - {"src": "testdata/*.csv", "dst": "/tmp/things"}
            - {"src": "testdata/*.yml", "dst": "/tmp/things"}

Copy file and making it executable is also supported:

        - name: copy file and make it executable
          copy:
            - {"src": "testdata/script.sh", "dst": "/tmp/script.sh", "chmod+x": true}
        - name: download file from remote to local
          copy: {"src": "/remote/path/data.csv", "dst": "./local/data.csv", "direction": "pull"}
        - name: download files with glob pattern
          copy: {"src": "/remote/logs/*.log", "dst": "./logs/", "direction": "pull", "mkdir": true}
        - name: download file with sudo on remote
          copy: {"src": "/etc/app/config.yml", "dst": "./configs/app.yml", "direction": "pull"}
          options: {sudo: true}
        - name: mixed upload and download
          copy:
            - {"src": "local/deploy.sh", "dst": "/remote/scripts/deploy.sh", "direction": "push"}
            - {"src": "/remote/logs/app.log", "dst": "./logs/app.log", "direction": "pull"}
            - {"src": "/remote/data/results.csv", "dst": "./data/results.csv", "direction": "pull", "force": true}

  sync
Synchronises directory from the local machine to the remote host(s). Optionally supports deleting files on the remote host(s) that don't exist locally with "delete": true flag. Another option is exclude which allows to specify a list of files to exclude from the sync.

        - name: sync directory
          sync: {"src": "testdata", "dst": "/tmp/things"}
        - name: sync directory with delete
          sync: {"src": "testdata", "dst": "/tmp/things", "delete": true}
        - name: sync directory with exclude
          sync: {"src": "testdata", "dst": "/tmp/things", "exclude": ["*.txt", "*.yml"]}

Sync also supports list format to sync multiple paths at once.

  delete
Deletes a file or directory on the remote host(s), optionally can remove recursively.

        - name: delete file
          delete: {"path": "/tmp/things.csv"}

        - name: delete directory recursively
          delete: {"path": "/tmp/things", "recur": true}

        - name: delete directory recursively with exclude
          delete: {"path": "/tmp/things", "recur": true, "exclude": ["*.txt", "*.yml"]}

Delete also supports a list format to remove multiple paths at once.

  wait
Waits for the specified command to finish on the remote host(s) with 0 error code. This command is useful when a user needs to wait for a service to start before executing the next command. Allows to specify the timeout as well as check interval.

        - name: wait for service to start
          wait: {"cmd": "curl -s --fail localhost:8080", "timeout": "30s", "interval": "1s"}

  echo
Prints the specified message to the console. This command is useful for debugging purposes and also to print the value of variables to the console.

        - name: print message
          echo: "hello world"
        - name: print variable
          echo: $some_var

  line
Manipulates lines in a file based on a regex pattern. This command supports three operations: delete lines matching a pattern, replace entire lines containing a pattern, or append a line if the pattern is not found. This is useful for simple configuration file modifications without complex sed/grep scripts.

        # Delete lines matching a pattern
        - name: remove comments
          line: {file: "/etc/config.conf", match: "^#", delete: true}
        # Replace entire lines containing a pattern
        - name: update setting
          line: {file: "/etc/config.conf", match: "^port=", replace: "port=8080"}
        # Append line if pattern not found
        - name: ensure setting exists
          line: {file: "/etc/config.conf", match: "^debug=", append: "debug=true"}

The line command:

•   Uses regex patterns for matching lines

•   For replace operation: replaces the entire line containing the match, not just the matching portion

•   Only performs one operation per command (delete, replace, or append)

•   Supports sudo for files requiring elevated permissions

•   Supports variable substitution in all fields

  Command options
Each command type supports the following options:

•   ignore_errors: if set to true the command will not fail the task in case of an error.

•   no_auto: if set to true the command will not be executed automatically, but can be executed manually using the --only flag.

•   local: if set to true the command will be executed on the local host (the one running the spot command) instead of the remote host(s).

•   sudo: if set to true the command will be executed with sudo privileges. This option is not supported for sync command type but can be used with any other command type.

•   sudo_password: specifies the secret key containing the sudo password. When set, the password will be piped to sudo -S for authentication. Requires the secret to be loaded via the secrets option.

•   only_on: allows to set a list of host names or addresses where the command will be executed. For example, only_on: [host1, host2] will execute a command on host1 and host2 only. This option also supports reversed conditions, so if a user wants to execute a command on all hosts except some, ! prefix can be used. For example, only_on: [!host1, !host2] will execute a command on all hosts except host1 and host2.

example setting ignore_errors, no_auto and only_on options:

          commands:
              - name: wait
                script: sleep 5s
                options: {ignore_errors: true, no_auto: true, only_on: [host1, host2]}

The same options can be set for the whole task as well. In this case, the options will be applied to all commands in the task but can be overridden for a specific command. This includes sudo_password which will be propagated to all commands unless a command specifies its own. Pls note: the command option cannot reset the boolean options that were set for the task. This limitation is due to the way the default values are set.

          - name: deploy-things
            on_error: "curl -s localhost:8080/error?msg={SPOT_ERROR}" # call hook on error
            options: {ignore_errors: true, no_auto: true, only_on: [host1, host2]}
            commands:
              - name: wait
                script: sleep 5s

Task-level sudo with password example:

          - name: system-updates
            options:
              sudo: true
              sudo_password: "ADMIN_PASSWORD"  # secret key name (not the actual password!)
              secrets: ["ADMIN_PASSWORD"]       # load secret from provider
            commands:
              - name: update packages
                script: apt-get update
              - name: upgrade packages
                script: apt-get upgrade -y
              - name: special command
                script: dpkg --configure -a
                options:
                  sudo_password: "SPECIAL_PASSWORD"  # overrides task-level with different secret
                  secrets: ["SPECIAL_PASSWORD"]

Security Warning: Never hardcode actual passwords in playbook files. The sudo_password field should contain the name of a secret key, not the password itself. Store actual passwords securely using one of the secrets providers (Spot DB, AWS Secrets Manager, Vault, etc.) or use environment variables.

  Command conditionals
cond: defines a condition for the command to be executed. The condition is a valid shell command that will be executed on the remote host(s) and if it returns 0, the primary command will be executed. For example, cond: "test -f /tmp/foo" will execute the primary script command only if the file /tmp/foo exists. The condition can be reversed by adding ! prefix, i.e. ! test -f /tmp/foo will pass only if the file /tmp/foo doesn't exist.

example installing curl package if not installed already:

          - name: "install curl"
            script: "yum install curl -y"
            options: {sudo: true}
            cond: "! command -v curl"

Example using sudo with password authentication:

          - name: "install package with sudo password"
            script: "apt-get update && apt-get install -y nginx"
            options:
              sudo: true
              sudo_password: "SUDO_PASS_KEY"   # name of the secret key (not the actual password!)
              secrets: ["SUDO_PASS_KEY"]       # load the secret from provider

Security Note: When using sudo_password, the password is briefly visible in the process list on the remote host during execution. This is an inherent limitation of piping passwords to sudo -S. While this approach is common in automation tools, be aware that any user on the remote system could potentially see the password via ps during execution. Consider this trade-off when deciding whether to use this feature in your environment.

currently conditions can be used with script and echo command types only.

  Deferred actions (on_exit)
Each command may have on_exit parameter defined. It allows executing a command on the remote host after the task with all commands is completed. The command is called regardless of the task's exit code.

This is useful in several scenarios:

•   a temporary script copied to the remote host and executed and should be removed after execution with on_exit: "rm -fv /tmp/script.sh"

•   a service should be restarted after the new version is deployed with on_exit: "systemctl restart myservice"

          - name: "copy script"
            copy: {src: "testdata/script.sh", "dst": "/tmp/script.sh", "chmod+x": true}
            on_exit: "rm -fv /tmp/script.sh" # register deferred action to remove script.sh after execution
          - name: "run script"
            script: "/tmp/script.sh"

In the example above, the script.sh is copied to the remote host, executed, and removed after completion of the task.

  Script Execution
Spot allows executing scripts on remote hosts, or locally if options.local is set to true. Scripts can be executed in two different ways, depending on whether they are single-line or multi-line scripts.

Single-line Script Execution

For single-line scripts, they are executed directly inside the shell with the optional parameters set to the command line. For example:

          commands:
              - name: some command
                script: ls -laR /tmp
                env: {FOO: bar, BAR: qux}

this will be executed as: FOO='bar' BAR='qux'ls -laR /tmp FOO=bar BAR=qux inside the shell on the remote host(s), i.e. sh -c "FOO='bar' BAR='qux'ls -laR /tmp FOO=bar BAR=qux".

Multi-line Script Execution

For multi-line scripts, Spot creates a temporary script containing all the commands, uploads it to the remote host (or keeps it locally if options.local is set to true), and executes the script. Environment variables are set inside the script, allowing the user to create complex scripts that include setting variables, conditionals, loops, and other advanced functionality. Scripts run with "set -e" to fail on error. For example:

        commands:
          - name: multi_line_script
            script: |
              touch /tmp/file1
              echo "Hello World" > /tmp/file2
              echo "Executing loop..."
              for i in {1..5}; do
                echo "Iteration $i"
              done
              echo "All done! $FOO $BAR
            env: {FOO: bar, BAR: qux}

this will create a temporary script on the remote host(s) with the following content and execute it:

        #!/bin/sh
        set -e
        export FOO='bar'
        export BAR='qux'
        touch /tmp/file1
        echo "Hello World" > /tmp/file2
        echo "Executing loop..."
        for i in {1..5}; do
          echo "Iteration $i"
        done
        echo "All done! $FOO $BAR"

By using this approach, Spot enables users to write and execute more complex scripts, providing greater flexibility and power in managing remote hosts or local environments.

Special Characters in Variables

When using variables that contain dollar signs ($), be aware that the shell will interpret them during execution. To preserve literal dollar signs (common in passwords, hashes, etc.), use single quotes when setting variables.

Examples:

        commands:
          - name: set bcrypt password
            script: |
              # Use single quotes to preserve literal dollar signs
              export BCRYPT_HASH='$2a$14$G.j2F3fm9wluTougUU52sOzePOvvpujjRrCoVp5qWVZ6qRJh58ISC'
              echo "Hash: $BCRYPT_HASH"  # Will print the correct hash
          - name: use password in env section
            script: echo "Password: $PASSWORD"
            env:
              # Single quotes preserve the literal value
              PASSWORD: '$2a$14$G.j2F3fm9wluTougUU52sOzePOvvpujjRrCoVp5qWVZ6qRJh58ISC'

          - name: normal variables work as expected
            script: echo "Home is $HOME"  # $HOME expands normally

This applies to all places where variables are used: scripts, environment sections, and when passing variables between commands.

Users can also set any custom shebang for the script by adding #! at the beginning of the script. For example:

        commands:
          - name: multi_line_script
            script: |
              #!/bin/bash
              touch /tmp/file1
              echo "Hello World" > /tmp/file2

  Passing variables from one script command to another
The spot allows passing variables from one command to another. This feature is especially useful when a command, often a script, sets a variable, and the subsequent command requires this variable. For instance, if one command creates a file and the file name is needed in another command. To pass these variables, a user must use the conventional shell's export directive in the initial script command. Subsequently, all variables exported in this initial command will be accessible in the following commands.

For example:

        commands:
          - name: first command
            script: |
              export FILE_NAME=/tmp/file1
              touch $FILE_NAME
          - name: second command
            script: |
              echo "File name is $FILE_NAME"
          - name: third command
            copy: {src: $FILE_NAME, dest: /tmp/file2}

Sometimes, exporting variables is not possible or not desired. For such cases, Spot allows to register variables explicitly using the register option.

For example:

        commands:
          - name: first command
            script: |
              FILE_NAME=/tmp/file1
              touch $FILE_NAME
              ANOTHER_VAR=foo
            register: [FILE_NAME, ANOTHER_VAR]

          - name: second command
            script: |
              echo "File name is $FILE_NAME, var is $ANOTHER_VAR"

          - name: third command
            copy: {src: $FILE_NAME, dest: /tmp/file2}

Another unique feature of the registered variables is that they can be used not only in the subsequent commands for the current task but also in the subsequent tasks. This allows users to pass variables between tasks. In other words, the registered variables are populated to the environment of all the tasks in the playbook, automatically.

example:

        tasks:
          - name: set_register_var
            commands:
              - name: some command
                script: |
                  echo good command 1
                  len=$(echo "file content" | wc -c)
                register: [len]
          - name: use_register_var
            commands:
              - name: some command
                script: |
                  echo "len: $len"

Register variable names also support template substitution, which allows dynamic variable names. Both predefined Spot variables and environment variables can be used in the templates:

        tasks:
          - name: register_with_template_vars
            commands:
              - name: register with host template
                script: |
                  # Create a variable with the host address in the name
                  export VAR_192.168.1.10="host-specific-value"
                register: ["VAR_{SPOT_REMOTE_ADDR}"]  # Expands to VAR_192.168.1.10

              - name: register with env var template
                script: |
                  # Create a dynamic variable based on the ENV_TYPE value
                  export CONFIG_production="prod-config-value"
                environment: { ENV_TYPE: "production" }
                register: ["CONFIG_{ENV_TYPE}"]  # Expands to CONFIG_production

              - name: check registered variables
                script: |
                  echo "Host-specific var: ${VAR_192.168.1.10}"
                  echo "Environment-specific var: ${CONFIG_production}"

This allows creating dynamic variable names that adapt to the current host, environment, or other context-specific values.

  Setting environment variables
Environment variables can be set with --env / -e cli option. For example: -e VAR1:VALUE1 -e VAR2:VALUE2. Environment variables can also be set in the environment file (default env.yml can be changed with --env-file / -E cli flag). For example:

        vars:
          VAR1: VALUE1
          VAR2: VALUE2

Environment variables can be used in the playbook file with the expected syntax: $VAR_NAME or ${VAR_NAME}. For example:

        commands:
          - name: some command
            script: echo $VAR1
          - name: another command
            copy: {"src": "testdata/*.csv", "dst": "$VAR2"}

In case of a conflict between environment variables set in the environment file and the cli, the cli variables will take precedence.

Important Note on Variable Expansion:

Spot performs its own simple variable substitution before executing a command. It directly replaces placeholders like $VAR, ${VAR}, or {VAR} with their defined values. This is a direct string replacement, not a full shell expansion.

This means:

•   Simple replacement: VAR: world in a script echo "Hello, $VAR" becomes echo "Hello, world".

•   Composition: You can build variables from others: env: {BAR: yyy, FOO: xxx$BAR} will result in FOO being xxxyyy.

•   Shell still runs: After Spot performs its substitution, the resulting string is executed by the shell. This means shell features like command substitution will still work, but they are interpreted by the shell, not by Spot. For example: env: {FOO: $(echo xxx)} will result in FOO being xxx because the shell executes $(echo xxx).

Because Spot's substitution is literal, it can lead to unexpected behavior with special characters (like $ in passwords or certain symbols in emojis). The shell might interpret these as part of its own syntax. To avoid this, use single quotes for values that should be treated literally, as explained in the Special Characters in Variables section.

  Targets
Targets are used to define the remote hosts to execute the tasks on. Targets can be defined in the playbook file or passed as a command-line argument. The following target types are supported:

•   hosts: a list of destination host names or IP addresses, with optional port and username, to execute the tasks on. Example: hosts: [{host: "h1.example.com", user: "test", name: "h1}, {host: "h2.example.com", "port": 2222}]. If no user is specified, the user defined in the top section of the playbook file (or override) will be used. If no port is specified, port 22 will be used.

•   groups: a list of groups from inventory to use. Example: groups: ["dev", "staging"}. A special group all combines all the groups.

•   tags: a list of tags from inventory to use. Example: tags: ["tag1", "tag2"}.

•   names: a list of host names from inventory to use. Example: names: ["host1", "host2"}.

All the target types can be combined, i.e. hosts, groups, tags, hosts and names all can be used together in the same target. To avoid possible duplicates, the final list of hosts is deduplicated by the host+ip+user.

example of targets set in the playbook file:

        targets:
          prod:
            hosts: [{host: "h1.example.com", user: "test"}, {"h2.example.com", "port": 2222, name: "h2"}]
          staging:
            groups: ["staging"]
          dev:
            groups: ["dev", "staging"]
            names: ["host1", "host2"]
          all-servers:
            groups: ["all"]
        tasks:
          - name: task1
            targets: ["dev", "host3.example.com:2222"]
            commands:
              - name: command1
                script: echo "Hello World"

Note: All the target types are available in the full playbook file only. The simplified playbook file only supports a single, anonymous target type combining hosts and names together.

        targets: ["host1", "host2", "host3.example.com", "host4.example.com:2222"]

in this example, the playbook will be executed on hosts named host1 and host2 from the inventory and on hosts host3.example.com with port 22 and host4.example.com with port 2222.

  Target overrides
There are several ways to override or alter the target defined in the playbook file via command-line arguments:

•   --inventory set hosts from the provided inventory file or url. Example: --inventory=inventory.yml or --inventory=http://localhost:8080/inventory.

•   --target set groups, names, tags from inventory or direct hosts to run the playbook on. Example: --target=prod (will run on all hosts in group prod) or --target=example.com:2222 (will run on host example.com with port 2222). User name can be provided as a part of the direct target address as well, i.e. --target=user2@example.com:2222

•   --user set the ssh user to run the playbook on remote hosts. Example: --user=test.

•   --key set the ssh key to run the playbook on remote hosts. Example: --key=/path/to/key.

  Target selection
The target selection is done in the following order:

•   if --target is set, it will be used.

    •   first Spot will try to match on target name in the playbook file.

    •   if no match is found, Spot will try to match on the group name in the inventory file.

    •   if no match is found, Spot will try to match on tags in the inventory file.

    •   if no match is found, Spot will try to match on hostname in the inventory file.

    •   if no match is found, Spot will try to match on host address in the playbook file.

    •   if no match is found, Spot will use it as a host address.

•   if --target is not set, Spot will try to check it targets list for the task. If set, it will use it following the same logic as above.

•   and finally, Spot will assume the default target.

  Dynamic targets
Spot offers support for dynamic targets, allowing the list of targets to be defined dynamically using variables. This feature becomes particularly useful when users need to ascertain a destination address within one task, and subsequently use it in another task. Here is an illustrative example:

        tasks:
          - name: get host
            targets: ["default"]
            script: |
              export thehost=$(curl -s http://example.com/next-host)
            options: {local: true}

          - name: run on host
            targets: ["$thehost"]
            script: |
              echo "doing something on $thehost"

In this example, the host address is initially fetched from http://example.com/next-host . Following this, the task "run on host" is executed on the host that was just identified. This ability to use dynamic targets proves beneficial in a variety of scenarios, especially when the list of hosts is not predetermined.

A practical use case for dynamic targets arises during the provisioning of a new host, followed by the execution of commands on it. Since the IP address of the new host isn't known beforehand, dynamic retrieval becomes essential.

The reason the first task specifies targets: ["default"] is because Spot requires some target to execute a task. In this case, all commands in "get host" tasks are local and won't be invoked on a remote host. The default target is utilized by Spot if no alternative target is specified via the command line.

  Inventory
The inventory file is a simple yml (or toml) that can represent a list of hosts or a list of groups with hosts. In case if both groups and hosts are defined, the hosts will be merged with groups and will add a new group named hosts.

By default, inventory is loaded from the file/url set in SPOT_INVENTORY environment variable. This is the lowest priority and can be overridden by inventory from the playbook (next priority) and --inventory flag (highest priority) . This is an example of the inventory file with groups

        groups:
          dev:
            - {host: "h1.example.com", name: "h1", tags:["us-east1", "vpc-1234567"]}
            - {host: "h2.example.com", port: 2233, name: "h2"}
            - {host: "h3.example.com", user: "user1"}
            - {host: "h4.example.com", user: "user2", name: "h4"}
          staging:
            - {host: "h5.example.com", port: 2233, name: "h5"}
            - {host: "h6.example.com", user: "user3", name: "h6"}

•   host: the hostname or IP address of the remote host.

•   port: the ssh port of the remote host. Optional, default is 22.

•   user: the ssh user of the remote host. Optional, default is the user defined in the playbook file or --user flag.

•   name: the name of the remote host. Optional.

•   tags: the list of tags of the remote host. Optional.

In case if port is not defined, the default port 22 will be used. If the user is not defined, the playbook's user will be used.

This is an example of the inventory file with hosts only (no groups)

        hosts:
          - {host: "hh1.example.com", name: "hh1"}
          - {host: "hh2.example.com", port: 2233, name: "hh2", user: "user1"}
          - {host: "h2.example.com", port: 2233, name: "h2", tags:["us-east1", "vpc-1234567"]}
          - {host: "h3.example.com", user: "user1", name: "h3"}
          - {host: "h4.example.com", user: "user2", name: "h4"}

This format is useful when you want to define a list of hosts without groups.

In each case, inventory is automatically merged and a special group all will be created that contains all the hosts.

Alternatively, the inventory can be represented using the TOML format.

  Export
Spot supports exporting all the destinations from selected/matched targets to the file or stdout. This is useful when users want to use the same hosts/ports/server-names/etc in other systems. By default, with --gen option, Spot will export to stdout in json format. To export to the file, --gen.output=/path/to/file option can be used.

This exported list of destinations can be consumed by another system, but practically it will require some conversion from the spot's json to the format that is supported by the system. This can be addressed by injecting jq (https://stedolan.github.io/jq/) into the mix but spot also offers a better solution - templating with the standard go templates. To turn this feature on, --gen.template=/path/to/template option can be used.

Example of the template file, showing all the fields that can be used:

        {{- range .}}
        "Name": "{{.Name}}"
        "Host:Port": "{{.Host}}:{{.Port}}"
        "User": "{{.User}}"
        "Tags": [{{range .Tags}}"{{.}}"{{end}}]
        {{- end -}}

for more info see go templates (https://pkg.go.dev/text/template)

  Runtime variables
Spot supports runtime variables that can be used in the playbook file. The following variables are supported:

•   {SPOT_REMOTE_HOST}: The remote hostname or IP address with port.

•   {SPOT_REMOTE_ADDR}: The remote hostname or IP address.

•   {SPOT_REMOTE_PORT}: The remote port.

•   {SPOT_REMOTE_NAME}: The remote custom name, set in inventory or playbook as name.

•   {SPOT_REMOTE_USER}: The remote username.

•   {SPOT_COMMAND}: The command name.

•   {SPOT_TASK}: The task name.

•   {SPOT_ERROR}: The error message, if any.

Variables can be used in the following places: script, copy, sync, delete, wait and env, for example:

        tasks:
            name: deploy-things
            commands:
              - name: copy configuration
                copy: {"src": "{SPOT_REMOTE_HOST}/conf.yml", "dst": "/tmp/conf.yml", "mkdir": true}
              - name: sync things
                sync: {"src": "testdata", "dst": "/tmp/{SPOT_TASK}/things"}
              - name: some command
                script: |
                  ls -laR /tmp/${SPOT_COMMAND}
                env: { FOO: bar, BAR: "{SPOT_COMMAND}-blah" }
              - name: delete things
                delete: {"loc": "/tmp/things/{SPOT_REMOTE_USER}", "recur": true}

  Ad-hoc commands
Spot supports ad-hoc commands that can be executed on the remote hosts. This is useful when all is needed is to execute a command on the remote hosts without creating a playbook file. This command is optionally passed as a first argument, i.e. spot "ls -la /tmp" and usually accompanied by the --target=<host> (-t <host>) flags. Example: spot "ls -la" -t h1.example.com -t h2.example.com.

All other overrides can be used with ad-hoc commands as well, for example --userand --key to specify the user and sshkey to use when connecting to the remote hosts. By default, Spot will use the current user and the default ssh key. Inventory can be passed to such commands as well, for example --inventory=inventory.yml.

Adhoc commands always sets verbose to true automatically, so the user can see the output of the command.

  Rolling Updates
Spot supports rolling updates, which means that the tasks will be executed on the hosts one by one, waiting for the previous host to finish before starting the next one. This is useful when you need to update a service running on multiple hosts but want to avoid downtime. To enable rolling updates, use the --concurrent=N flag when running the spot command. N is the number of hosts to execute the tasks concurrently. Example: spot --concurrent=2. In addition, the user can use a built-in wait command to wait for a service to start before executing the next command. See the Command Types section for more details. Practically, the user will have a task with a series of commands, where the last command will wait for the service to start by running a command like curl -s --fail localhost:8080 and then the task will be executed on the next host.

  Secrets
Spot supports secrets, which are encrypted string values that can be used in the playbook file. This feature is useful for storing sensitive information, such as passwords or API keys. Secrets are encrypted, and their values are decrypted at runtime. Spot supports three types of secret providers: built-in, Hashicorp Vault, and AWS Secrets Manager. Other providers can be added by implementing the SecretsProvider interface with a single GetSecrets method.

Using secrets is simple. First, users need to define a secret provider in the command line options or environment variables. Then, users can add secrets to any command in the playbook file by setting options.secrets, as shown in the following example:

        tasks:
          - name: access sensitive data
            commands:
              - name: read api response
                script: |
                  curl -s -u ${user}:${password} https://api.example.com
                  curl https://api.example.com -H "Authorization: Bearer ${token}"
                options:
                  secrets: [user, password, token]

In this case secrets for keys user, password and token will be read from the secrets provider, decrypted at runtime, and passed to the command in the environment. Please note: if a user runs spot with the --verbose or --dbg flag, the secrets will be replaced with **** in the output. This is done to prevent secrets from being displayed or logged.

Sometimes, users may want to use the same set of secrets in multiple commands. To avoid repeating the secrets in each command, users can set secrets at the task level, as shown in the following example:

        tasks:
          - name: access sensitive data
            commands:
              - name: read api response
                script: |
                  curl -s -u ${user}:${password} https://api.example.com
                  curl https://api.example.com -H "Authorization: Bearer ${token}"
            options:
              secrets: [user, password, token]

  Built-in Secrets Provider
Spot includes a built-in secrets provider that can be used to store secrets in SQLite, MySQL, or Postgresql databases. The provider can be configured using the following command line options or environment variables:

•   --secrets.provider=spot: selects the built-in secret`s provider.

•   --secrets.conn or $SPOT_SECRETS_CONN: the connection string to the database

    •   sqlite: file:///path/to/database.db or /path/to/database.sqlite or /path/to/database.db, default: spot.db

    •   mysql: user:password@tcp(host:port)/dbname

    •   postgresql: postgres://user:password@host:port/database?option1=value1&option2=value2

•   --secrets.key or $SPOT_SECRETS_KEY: the encryption key to use for decrypting secrets. If not provided, Spot will prompt for it securely (without echoing to screen). The key can also be piped in for automation: echo "mykey" | spot ...

If spot provider is selected, the table spot_secrets will be created in the database. The table has the following columns: skey and sval. The skey column is the secret key, and the sval column is the encrypted secret value. The skey column is indexed for faster lookups. It is recommended to use application-specific prefixes for the secret keys, for example, system-name/service-name/secret-key. This will allow to use the same database for multiple applications without conflicts.

The built-in secrets provider uses strong cryptography techniques to ensure the safety of your secrets. Below is a summary of the security methods employed:

•   Argon2 key derivation: The Argon2 key derivation function (argon2.IDKey) is used to derive a 32-byte key from the provided user key and a randomly generated salt. This function is memory-hard and designed to be resistant to GPU-based attacks, providing increased security for your secrets.

•   NaCl SecretBox encryption: Secrets are encrypted and decrypted using the NaCl SecretBox (https://pkg.go.dev/golang.org/x/crypto/nacl/secretbox) package, which provides authenticated encryption with additional data. It uses XSalsa20 for encryption and Poly1305 for authentication, ensuring the integrity and confidentiality of the stored secrets.

•   Random nonces and salts: Spot generates random nonces for each encryption operation and random salts for each key derivation operation. These values are produced using the crypto/rand package, which generates cryptographically secure random numbers.

•   Base64 encoding: Encrypted secret values are stored in the database as Base64 encoded strings, which provides a safe and compact way to represent binary data in text form.

These methods work together to provide a robust and secure way to manage secrets in Spot. By using the built-in secrets provider, users can be confident that their sensitive data is securely stored and protected from unauthorized access.

  Hashicorp Vault Secrets Provider
Spot supports Hashicorp Vault as a secrets provider. To use it, a user needs to set the following command line options or environment variables:

•   --secrets.provider=vault: selects the Hashicorp Vault secrets provider.

•   --secrets.vault.token or $SPOT_SECRETS_VAULT_TOKEN: the Vault token to use for authentication.

•   --secrets.vault.url or $SPOT_SECRETS_VAULT_URL: the Vault server url.

•   --secrets.vault.path or $SPOT_SECRETS_VAULT_PATH: the path to the secrets in Vault.

  AWS Secrets Manager Secrets Provider
Spot supports AWS Secrets Manager as a secrets provider. To use it, a user needs to set the following command line options or environment variables:

•   --secrets.provider=aws: selects the AWS Secrets Manager secrets provider.

•   --secrets.aws.region or $SPOT_SECRETS_AWS_REGION: the AWS region to use for authentication.

•   --secrets.aws.access-key or $SPOT_SECRETS_AWS_ACCESS_KEY: the AWS access key to use for authentication.

•   --secrets.aws.secret-key or $SPOT_SECRETS_AWS_SECRET_KEY: the AWS secret key to use for authentication.

note: by default, the AWS Secrets Manager secrets provider will use the default AWS credential. This means that the provider will use the credentials from the environment variables AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY.

  Ansible Vault Secrets Provider
Spot gives the ability to use full encrypted YAML files by ansbile-vault (https://docs.ansible.com/ansible/latest/cli/ansible-vault.html)

--secrets.provider=ansible-vault: selects the Ansible Vault secrets provider. --secrets.ansible.path or $SPOT_SECRETS_ANSIBLE_PATH path to the ansible-vault file --secrets.ansible.secret or $SPOT_SECRETS_ANSIBLE_SECRET secret string for decrypting ansible-vault file

note: encrypted values in the vault should be in the following format key[string]:value[string] without nested lists and maps.

  Managing Secrets with spot-secrets
Spot provides a simple way to manage secrets for builtin providers using the spot-secrets utility. This command can be used to set, delete, get, and list secrets in the database.

•   spot-secrets set <key> <value>: sets the secret value for the specified key.

•   spot-secrets get <key>: gets the secret value for the specified key.

•   spot-secrets delete <key>: deletes the secret value for the specified key.

•   spot-secrets list: lists all the secret keys in the database.

Security Note: The encryption key (-k/--key) can be provided via command line, environment variable (SPOT_SECRETS_KEY), or if omitted, will be prompted for securely without echoing to the screen. This prevents the key from being visible in shell history or process lists.

        Usage:
          spot-secrets [OPTIONS] <command>
        Application Options:
          -k, --key=  key to use for encryption/decryption [$SPOT_SECRETS_KEY]
          -c, --conn= connection string to use for the secrets database (default: spot.db) [$SPOT_SECRETS_CONN]
              --dbg   debug mode
        Help Options:
          -h, --help  Show this help message
        Available commands:
          del   delete a secret
          get   retrieve a secret
          list  list secrets keys
          set   add a new secret

  Why Spot?
Spot is simple. It only has a few basic commands with a very limited set of options and flags. The playbook is just a list of commands to run, plus a list of remote targets to apply those commands against. Each command is made to be as intuitive and as direct as possible. Despite its simplicity, Spot is surprisingly powerful and can help get things done. This tool was built out of frustration with the complexity of similar tools. All I wanted was something that is simple, easy to use, easy to understand, and capable of handling most of the usual deployment tasks. I didn't want to have to check the documentation or resort to googling every time I used it. Spot is the result of that effort.

Spot is designed to provide a simple, efficient, and flexible solution for deployment and configuration management. It addresses the need for a tool that is easy to set up and use, while still offering powerful features for managing infrastructure.

Below are some of the reasons why you should consider using Spot:

1.  Keeps it simple: Spot concentrates on one task and one task only - deploying things with minimal headache. It doesn't try to solve all the problems in the universe; instead, it offers a focused and sufficient set of features to address the majority of use cases without unnecessary complexity.

2.  Conceptual simplicity and predictability: Spot embraces simplicity in its design and execution. Rather than being declarative, tasks contain a direct list of straightforward commands to achieve the desired outcome. This approach ensures that Spot is highly predictable, as it strictly follows the user's instructions without attempting to interpret or guess their intentions. This makes it easier for users to understand and control the deployment process.

3.  User-friendly: Spot prioritizes user-friendliness by providing a limited and intuitive set of command line options, making it easy to get started with deploying projects. Additionally, Spot uses well-known YAML or TOML formats for its playbook and inventory files. The minimalistic structure of these files enhances readability and makes them more approachable for users who want to focus on deploying their projects without getting bogged down in complex syntax or unnecessary details. For simpler use cases, Spot also offers a simplified playbook format that further streamlines the deployment process.

4.  Full control: Spot gives users full control over their deployments. Users can select any set of tasks and hosts, and even limit which commands are executed. Spot provides a dry mode that allows users to preview the changes that will be made before executing the playbook. The verbose modes provide many details to help users understand what's going on during the deployment process, while the debug mode gives maximum detailed logs for users who need to investigate deeper.

5.  Safe and secure: Spot prioritizes security, offering seamless integration with various secret vault solutions, as well as providing a built-in option. This ensures that sensitive information is handled securely, giving users peace of mind while managing their infrastructure.

6.  Flexible and extensible: Spot is designed to adapt to various deployment and configuration scenarios, managing different targets like production, staging, and development environments. It supports executing tasks on remote hosts directly or through inventory files and URLs, integrating with existing inventory management solutions. Spot also allows for custom script execution on remote hosts and offers built-in commands for common operations, enabling the creation of tailored workflows for deployment and configuration management.

7.  Concurrent Execution and Rolling Updates: Spot supports concurrent execution of tasks, speeding up deployment and configuration processes by running on multiple hosts simultaneously. This is especially helpful when managing large-scale infrastructure or when time is of the essence. Spot also allows for rolling updates with user-defined wait commands, ensuring smooth and controlled deployment of changes across the infrastructure.

8.  Customizable: Spot offers various command-line options and environment variables that allow users to tailor its behavior to their specific requirements. Users can easily modify the playbook file, task, target, and other parameters, as well as control the execution flow by skipping or running specific commands.

9.  Lightweight: Spot is a lightweight tool, written in Go, that does not require heavy dependencies or a complex setup process. It can be easily installed and run on various platforms, making it an ideal choice for teams looking for a low-overhead solution for deployment and configuration management.

10. Ready-to-use binaries and packages: Spot is available as ready-to-use binaries and packages for various platforms, including Linux, macOS, and Windows. Users can download and install the appropriate package for their platform, making it easy to get started with Spot without having to build from source. Spot provides binaries for both x86, arm, and arm64 architectures, as well as rpm, deb and apk packages for Linux users.

In conclusion, Spot is a powerful and easy-to-use tool that simplifies the process of deployment and configuration management while offering the flexibility and extensibility needed to cater to various use cases.

  Is it replacing Ansible?
Spot is not designed as a direct replacement for Ansible; however, in certain use cases, it can address the same challenges effectively. While both tools can be used for deployment and configuration management, there are some key differences between them:

•   Complexity: Ansible is a more feature-rich and mature tool, offering a wide range of modules and plugins that can automate many different aspects of infrastructure management. Spot, on the other hand, is designed to be simple and lightweight, focusing on a few core features to streamline the deployment and configuration process.

•   Learning Curve: Due to its simplicity, Spot has a lower learning curve compared to Ansible. It's easier to start with Spot, making it more suitable for smaller projects or teams with limited experience in infrastructure automation. Ansible, while more powerful, can be more complex to learn and configure, especially for newcomers.

•   Customization: While both tools offer customization options, Ansible has a more extensive set of built-in modules and plugins that can handle a wide range of tasks out of the box. Spot, in contrast, relies on custom scripts and a limited set of built-in commands for its functionality, which might require more manual configuration and scripting for certain use cases.

•   Community and Ecosystem: Ansible has a large and active community, as well as a vast ecosystem of roles, modules, and integrations. This can be beneficial when dealing with common tasks or integrating with third-party systems. Spot, being a smaller and simpler tool, doesn't have the same level of community support or ecosystem.

•   Ease of installation and external dependencies: One of the most significant benefits of Spot is that it has no dependencies. Being written in Go, it is compiled into a single binary that can be easily distributed and executed on various platforms. This eliminates needing to install or manage any additional software, libraries, or dependencies to use Spot. Ansible, on the other hand, is written in Python and requires Python to be installed on both the control host (where Ansible is run) and the managed nodes (remote hosts being managed). Additionally, Ansible depends on several Python libraries, which must be installed and maintained on the control host. Some Ansible modules may also require specific libraries or packages to be installed on the managed nodes, adding to the complexity of managing dependencies.

Spot is an appealing choice for those seeking a lightweight, simple, and easy-to-use tool for deployment and configuration management, especially for smaller projects or when extensive features aren't necessary. Its single binary distribution, easy-to-comprehend structure, and minimal dependencies offer a low-maintenance solution. However, if a more comprehensive tool with a wide range of built-in modules, plugins, and integrations is needed, Ansible may be a better fit. While Ansible has advanced features and a robust ecosystem, its reliance on Python and additional libraries can sometimes be less convenient in certain environments or situations with specific constraints.

  Getting the latest development version
If you want to try the latest development version, you can install it directly from the master branch. There are two ways to do this:

•   Using go get: go install github.com/umputun/spot/cmd/spot@master and go install github.com/umputun/spot/cmd/secrets@master. Note that this will install the latest development version of spot and secrets, which may not be stable or fully tested.

•   Using git: git clone github.com/umputun/spot then cd spot and make build. This will install the latest development version of spot and secrets to spot/.bin/spot and spot/.bin/sport-secrets, respectively.

pls note that you need to have go 1.16+ installed on your machine.

  Status
The project is currently in active development, and breaking changes may occur until the release of version 1.0. However, we strive to minimize disruptions and will only introduce breaking changes when there is a compelling reason to do so.

Update: Version 1 has been released and is now considered stable. We do not anticipate any breaking changes for this version.

  Contributing
Please feel free to open a discussion, submit issues, fork the repository, and send pull requests. See CONTRIBUTING.md (https://github.com/umputun/spot/blob/master/CONTRIBUTING.md) for more information.

  License
This project is licensed under the MIT License. See the LICENSE file for more information.