git2consul

git2consul

git2consul takes one or many git repositories and mirrors them into Consul KVs. The goal is for organizations of any size to use git as the backing store, audit trail, and access control mechanism for configuration changes and Consul as the delivery mechanism.

Installation

npm install git2consul

Requirements / Caveats

• git2consul does most of its Git work by shelling out to git. Git must be installed and on your path.
• git2consul does the rest of its work by calling Consul's REST API. A Consul agent must be running on localhost.
• git2consul requires write access to the KV store of its Consul agent.
• git2consul has only been tested on Unix.

Configuration

git2consul expects to be run on the same node as a Consul agent. git2consul expects its own configuration to be stored as a JSON object in '/git2consul/config' in your Consul KV. The utility utils/config_seeder.js will take a JSON file and place it in the correct location for you.

Configuration Format

{
  "version": "1.0",
  "logger" : {
    "name" : "git2consul",
    "streams" : [{
      "level": "trace",
      "stream": "process.stdout"
    },
    {
      "level": "debug",
      "type": "rotating-file",
      "path": "/var/log/git2consul/git2consul.log"
    }]
  },
  "repos" : [{
    "name" : "vp_config",
    "local_store": "/tmp/git_cache",
    "url" : "ssh://stash.vistaprint.net/team_configuration_data.git",
    "branches" : ["development", "staging", "production"],
    "hooks": [{
      "type" : "stash",
      "port" : "5050",
      "url" : "/gitpoke"
    },
    {
      "type" : "polling",
      "interval" : "1"
    }]
  },{
    "name" : "github_data",
    "local_store": "/tmp/git_cache",
    "url" : "[e-mail]:ryanbreen/git2consul_data.git",
    "branches" : [ "master" ],
    "hooks": [{
      "type" : "github",
      "port" : "5151",
      "url" : "/gitpoke"
    }]
  }]
}

The above example illustrates a 2 repo git2consul setup: one repo lives in an on-premises Git solution and the other is hosted at github. The hooks array under each repository defines how git2consul will be notified of changes. git2consul supports Atlassian Stash, Atlassian Bitbucket, GitHub webhooks as well as a basic polling model.

Note that multiple webhooks can share the same port. The only constraint is that webhooks for different repos do not share the same port and path.

The above example also logs to stdout as well as to file. Logging is handled via Bunyan. The value of the logger property is passed to the Bunyan createLogger() method, so any configuration supported by vanilla Bunyan will work out of the box in git2consul.

No Daemon Mode

If there are no webhooks or polling watchers configured, git2consul will terminate as soon as all tracked repos and branches have been synced with Consul. If you would like to force git2consul not to attach any webhooks or polling watchers, you can either pass the command-line switch -n or include the field no_daemon: true at the top level of your config JSON.

How it works

git2consul uses the name and branches of configured repos to namespace the created KVs. The goal is to allow multiple teams to use the same Consul agents and KV store to migrate configuration data around a network without needing to worry about data conflicts. In the above example, a settings file stored at foo_service/settings.json in the development branch of the repo vp_config would be persisted in Consul as vp_config/development/foo_service/settings.json.

If you are using a more Twelve-Factor approach, where you wish to configure your applications via environment variables, you would store these settings as files in Git whose name is the key and whose body is the value. For example, we could create the file foo_service/log_level with the body trace in the development branch of the foo_service repo and git2consul will create the KV vp_config/development/foo_service/log_level with the value trace.

As changes are detected in the specified Git repos, git2consul determines which files have been added, updated, or deleted and replicates those changes to the KV. Because only changed branches and files are analyzed, git2consul should have a very slim profile on hosting systems.

Clients

A client system should query Consul for the subset of the KV containing the data relevant to its operation. To extend the above example, our foo_service on the development network might subscribe to the KV root vp_config/development/foo_service and emit any changes to disk (via something like fsconsul) or environment variables (via something like envconsul).

Tokens

If you are using tokens for ACLs, you can pass a token to git2consul by specifying the TOKEN environment variable. git2consul requires read/write access to your KV. The purpose of git2consul is to treat git as the single source of truth for KVs, so it typically makes the most sense to give all other users a read-only token to the KV.

CI

Builds are automatically run by Travis on any push or pull request.

License

Apache 2.0