Maestro

A slim app to cover your service discovery needs.

• A service to register/deregister an app, do health pings and query for service addresses
• Every party uses the same auth token
• Can be run with HTTP or HTTPS
• If an app does not send a ping within a configurable interval, it is considered dead and removed from the registry

Maestro comes as a single binary for the popular operating system and has no dependencies. It just needs an open TCP port to be reachable.

Configuration

bind_address: 'http://localhost:9200'
auth_token: 123abc # change this to something secure
die_after: 5m # supply time units, e.g. 2h12m52s. default is 5 minutes
certificate_file:
key_file:

The bind address specifies which host, if any, and which port Maestro binds to. When the bind address is actually http://localhost:9200, Maestro is only reachable via localhost. If you want to bind any IP address, use http://:9200. If you also want to use TLS, supply the paths to a certificate and key file in PEM format and use the bind address https://:9200.

All configuration values can be overwritten using environment variables; they have higher precedence than configuration file values, if they are set.

Available environment variables are

• MAESTRO_BIND_ADDRESS
• MAESTRO_AUTH_TOKEN
• MAESTRO_DIE_AFTER
• MAESTRO_CERTIFICATE_FILE
• MAESTRO_KEY_FILE

API

The API route prefix is /api/v1.

You can also use the Maestro Go SDK and the Maestro .NET SDK.

Use the custom X-Registry-Token header to supply the authentication token.

Registration

POST /register

with the request body

{
    "id": "some-service-handle",
    "address": "http://localhost:9001"
}

registers an app with the given ID under the specified address which is then queryable by other parties.

Deregistration

DELETE /deregister?id=some-service-id

removes the entry with the supplied service ID from the registry.

Query

GET /query?id=some-service-id

queries the registry for the entry with the supplied ID. The response body looks like this:

{
    "id": "some-service-id",
    "address": "http://localhost:9001",
    "last_ping": "2021-12-05T23:54:07.844640791+01:00"
}

Ping

PUT /ping?id=some-service-id

signals that the app which sends out the ping is still alive and working.