serv

SERV

serv is a helper cli application used to simplify and coordinate the startup of multiple services, all you need to do is define a yaml file with the list of comments to execute.

Key Features

• Clone repositories automatically into the specified folder if git project haven't been cloned yet.
• Specify a start up command for each repository
• Specify multiple health check commands for each repository
• Specify multiple post condition commands for each repository
• Block the execution of command groups while health checks and post conditions are executing
• Ability to run app in verbose mode as well as in silent mode.

Installation

Install golang on your operating system and simply run go get -u github.com/0nedark/serv to install serv.

Verify installation

To test that serv is installed correctly run which serv you should see the path where the application is installed. If which serv produces no output then you probably need to export PATH=$PATH:$GOPATH/bin add this export to your ~/.bashrc or equivalent.

Configuration

serv.yml configuration

order: ['group_a', 'group_b']
groups:
  group_a: [{...}, ...]
  group_b: [{...}, ...]

The start up of services is configured with the serv.yaml file. The root of this yaml file defines order, groups

order

Order is an array of string where each string refers to a specific group. This is used to define te order in which groups are executed.

groups

group_a:
  - url: git@github.com:0nedark/repo-name.git
    path: ../B
    command: echo test
    healthchecks: [{...}, ...]
    postconditions: [{...}, ...]
    
  - command: echo test
    healthchecks: [{...}, ...]
    postconditions: [{...}, ...]

Groups are a key value pair where the key is the name of the group and the value defines an array of services. Groups are executed sequentially in the order defined. Consecutive group is not executed until all health checks and post conditions of the current group pass.

service

- url: git@github.com:0nedark/repo-name.git
  path: ../B
  command: echo test
  healthchecks: [{...}, ...]
  postconditions: [{...}, ...]

Each service object defines the following fields command, healthchecks and postconditions as well as two optional fields url and path. The two optional fields can be used to define a repository that needs to be cloned, url defines repository url and path specifies where to clone the repository. If your repository is private you should still be able to clone it as long as you use the ssh repo url and you have ssh-agent running with your credentials added with ssh-add. In addition, path is also used to define the context in which all commands will be executed for this service, path and url must be provided together and you can't provide path on it's own. If no path is provided then the current working directory will be used as the context.

command

command: echo test

Command defines a single shell command to be executed. This should be used to run you startup script. If this command fails serv will terminate with error.

healthchecks

healthchecks:
  - command: echo test
    timeout: 10
    sleep: 5
  - command: cd .
    timeout: 60
    sleep: 5

A list of command like objects that are executed as soon as the service's command returns with no errors. Each health check command in the current group is executed in parallel, repeatedly, every sleep number of seconds, until it either returns with success or a timeout is reached. If any of the health checks fail serv will terminate with error.

postconditions

A list of commands that are executed as soon as the healthchecks return with no errors. Each post condition command in the current group is executed in parallel. If any of the post conditions fail serv will terminate with error.

serv.yml example

order: [group_a, group_b]
groups:
  group_a:
    - command: echo starting A
      healthchecks:
        - command: echo "healthcheck A"
          timeout: 10
          sleep: 5
      postconditions:
        - command: echo postcondition A
    - url: https://github.com/0nedark/serv.git
      path: ../B
      command: echo starting B
      healthchecks:
        - command: echo healthcheck B
          timeout: 60
          sleep: 5

  group_b:
    - url: https://github.com/0nedark/serv.git
      path: ../C
      command: echo starting C
      healthchecks:
        - command: echo healthcheck C
          timeout: 60
          sleep: 5