etcd-discovery-ruby v1.2.1

Ruby gem implementing etcd-discovery.

Configure etcd client

Default client does not use SSL and connects to http://localhost:2379.

EtcdDiscovery.configure do |config|
  config.use_ssl = true                            # Default: false
  config.cacert = "/etc/ssl/cacert.pem"            # nil
  config.ssl_key = "/etc/ssl/service/private.key"  # nil
  config.ssl_cert = "/etc/ssl/service/public.cert" # nil
  config.host = "etcd-host"                        # Default: "localhost"
  config.port = 2379                               # Default: 2379
  config.register_ttl = 5                          # Default: 10
  config.register_renew = 4                        # Default: 8
end

Get hosts for a particular service

hosts = EtcdDiscovery.get("service").all
hosts.each do |h|
  puts h.to_uri
end

Get hosts for a particular shard

hosts = EtcdDiscovery.get("service", shard: "shard-0").all
hosts.each do |h|
  puts h.to_uri
end

Get the service URI

EtcdDiscovery.get("service").to_uri

If the service is public, this returns the URI stored in /services_infos/<service>. Otherwise, it returns the URI of one registered host.

Warning

Calling to_s directly on a host or collection does not expose credentials: the password is redacted.

Use to_uri or to_private_uri before calling to_s when you need the full URI with credentials.

Code	Password Redacted
`EtcdDiscovery.get("app-scheduler").one.to_uri`	No
`EtcdDiscovery.get("app-scheduler").one.to_uri.to_s`	No
`EtcdDiscovery.get("app-scheduler").to_uri`	No
`EtcdDiscovery.get("app-scheduler").one.to_s`	Yes
`EtcdDiscovery.get("app-scheduler").to_s`	Yes

Get the URI of one shard

EtcdDiscovery.get("service", shard: "shard-0").to_uri

Get the URI of one registered node

EtcdDiscovery.get("service").one.to_uri

Get the private URI of one registered node

EtcdDiscovery.get("service").one.to_private_uri

Register a service

This returns an EtcdDiscovery::Registrar and starts the registration loop in a background thread.

registration = EtcdDiscovery.register "service", {
  'name' => "hostname",                         # Mandatory: Hostname of where the service is deployed
  'ports' => {                                  # Mandatory: Ports opened by the service
    'http'=> '80',
    'https' => '443'
  },
  'user' => "testuser",                         # Optional: If your service use basic auth: the username to access your service
  'password' => "secret",                       # Optional: If your service use basic auth: the password to access your service
  'public' => true,                             # Optional: Is your service accessible via an external network (or via a load balancer). Setting this to true will enable credentials synchronization.
  'critical' => true,                           # Optional: Is your service critical? This is just a tag and have no impact on the registration process
  'shard' => 'shard-0',                         # Optional: The shard this host belongs to
  'private_hostname' => 'my-host.internal.com', # Optional: The hostname of the service in the private network
  'private_ports' => {                          # Optional: The ports of the service in the private network
    'http' => '8080',
    'https' => '80443'
  }
}

registration.stop

Listen to credentials change

When a service is public and has credentials, user and password are synced across all the hosts of the service.

You can fetch the current user and password from the EtcdDiscovery::Registrar returned by register.

registration = EtcdDiscovery.register service, host

registration.user     # The current user (it can change at any time)
registration.password # The current password (it can change at any time)

Release a New Version

Bump new version number in:

CHANGELOG.md
README.md
etcd-discovery.gemspec Commit, tag and create a new release:

version="1.2.1"

git switch --create release/${version}
git add CHANGELOG.md README.md etcd-discovery.gemspec
git commit -m "Bump v${version}"
git push --set-upstream origin release/${version}
gh pr create --reviewer=leo-scalingo --title "$(git log -1 --pretty=%B)"

Once the pull request merged, you can tag the new release.

git tag v${version}
git push origin master v${version}
gh release create v${version}

The title of the release should be the version number and the text of the release is the same as the changelog.

etcd-discovery

Runtime