Spot

Spot (aka simplotask) is a powerful and easy-to-use tool for effortless deployment and configuration management. It allows users to define a playbook with the 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.

Features

• Define tasks with a list of commands and the list of target hosts.
• Support for remote hosts specified directly or through inventory files/URLs.
• Everything can be defined in a simple YAML or TOML file.
• Run scripts on remote hosts as well as on the localhost.
• Built-in commands: script, copy, sync, delete, echo and wait.
• Concurrent execution of task on multiple hosts.
• Ability to wait for a specific condition before executing the next command.
• Customizable environment variables.
• Support for secrets stored in the built-in secrets storage, Vault or AWS Secrets Manager.
• Ability to override list of destination hosts, ssh username and ssh key file.
• Skip or execute only specific commands.
• Catch errors and execute a command hook on the local host.
• Debug mode to print out the commands to be executed, output of the commands, and all the other details.
• Dry-run mode to print out the commands to be executed without actually executing them.
• Ad-hoc mode to execute a single command on a list of hosts.
• A single binary with no dependencies.

Getting Started

• Install Spot by download the latest release from the 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 -t flags: spot --task=deploy-things -t prod. This will execute only the deploy-things task for the prod target.

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

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

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

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

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

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 to be used. 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 host name, 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 the use of the SSH agent for authentication. Defaults to false. User can also set the environment variable SPOT_SSH_AGENT to define the value.
• --shell - shell to use for remote ssh execution, default is /bin/sh. User can also set the environment variable SPOT_SHELL 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. User 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 to use when 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.
• -E, --env-file=: Sets the environment variables from file to be used during the task execution. Default is env.yml. Can be also set with environment variable SPOT_ENV_FILE.
• --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.
• --dbg: Enables debug mode, providing even more detailed output and error messages during the task execution as well as 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 can be 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 can be 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
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 felt 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
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 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 on 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, user, and ssh_key fields, while the full playbook does. See the Task details section for more information.
• The simplified playbook also has target field (in addition to targets) allows to set a single host/name only. This is useful when user 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 playbook file for the specified task.
• targets - list of target names, group, 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 supported in the full playbook type only

All tasks are executed sequentially one 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 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 and this stackoverflow post.

copy

Copies a file from the local machine to the remote host(s). If mkdir is set to true the command will create the destination directory if it doesn't exist, 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 remote host(s) 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"}

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 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 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

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.
• 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 command on host1 and host2 only. This option also supports reversed condition, so if user wants to execute command on all hosts except some, ! prefix can be used. For example, only_on: [!host1, !host2] will execute command on all hosts except host1 and host2.
• 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. Condition can be reversed by adding ! prefix, i.e. ! test -f /tmp/foo will pass only if file /tmp/foo doesn't exist. Please note that cond option supported for script command type only.

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]}

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.

User 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

Spot allows to pass 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, 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}

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 variable 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.

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"}. 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 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 directly hosts to run 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. [email protected]: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 found, Spot will try to match on group name in the inventory file.
  • if no match found, Spot will try to match on tags in the inventory file.
  • if no match found, Spot will try to match on host name in the inventory file.
  • if no match found, Spot will try to match on host address in the playbook file.
  • if no match found, Spot will use it as a host address.
• if --target is not set, Spot will try 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) what can represent a list of hosts or a list of groups with hosts. In case if both groups and hosts defined, the hosts will be merged with groups and will add a new group named hosts.

By default, inventory 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 host name 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 not defined, the default port 22 will be used. If user 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 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 export all the destination from selected/matched targets to the file or stdout. This is useful when user 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 other 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 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

Runtime variables

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

• {SPOT_REMOTE_HOST}: The remote host name or IP address.
• {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:
  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 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 adhoc 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 on concurrently. Example: spot --concurrent=2. In addition, user can use a builtin wait command to wait for a service to start before executing the next command. See the Command Types section for more details. Practically, 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 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.

Built-in Secrets Provider

Spot includes a built-in secrets provider that can be used to store secrets in sqlite, mysql or postgresql database. 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 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 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, user can be confident that your 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, 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, 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 ability to use full encrypted YAML files by ansbile-vault

--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 next 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 provider 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.

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 documentation or resort to googling every time I used it. Spot is the result of that effort.

Getting 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 for more information.

License

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