mongoconn

Shared MongoDB connection module for the Oktopus services: one place that decides which environment variables configure the client, how credentials are applied, how a service waits for the database at boot and how it watches the connection afterwards.

import "github.com/OktopUSP/mongoconn"

cfg := mongoconn.ConfigFromEnv(ctx, "CONTROLLER", mongoconn.StandardDefaults)
client, err := mongoconn.Connect(cfg) // blocks, with backoff, until MongoDB answers an authenticated ping
if err != nil {
	// Connect only fails when ctx ends, i.e. the service is shutting down.
}
go mongoconn.Monitor(ctx, client, slog.Default())

Environment

Variable	Default	Notes
MONGO_URI	mongodb://localhost:27017	Connection string. Credentials embedded in it (user:password@) take precedence over the variables below.
MONGO_PASSWORD	(empty)	The switch: while empty the client connects without authentication.
MONGO_USER	oktopus	Only used when MONGO_PASSWORD is set.
MONGO_AUTH_SOURCE	admin	Database the user was created in. Only used when MONGO_PASSWORD is set.
<PREFIX>_MONGO_MAX_POOL_SIZE	per service (StandardDefaults: 50)
<PREFIX>_MONGO_MIN_POOL_SIZE	0
<PREFIX>_MONGO_MAX_CONNECTING	2
<PREFIX>_MONGO_CONNECT_TIMEOUT_SECONDS	10
<PREFIX>_MONGO_SERVER_SELECTION_TIMEOUT_SECONDS	10

<PREFIX> is the argument passed to ConfigFromEnv, so each service keeps its own pool knobs while the URI and the credentials are shared.

Why the ping is not client.Ping

A mongod started with --auth answers the ping command even to an anonymous client, so a service missing its password would log "connected" and fail on its first real query. mongoconn.Ping runs listDatabases with authorizedDatabases: true instead: it works anonymously on a server without --auth, works for any authenticated user whatever its roles, and is refused when the server requires authentication.

Behaviour

• Connect retries with exponential backoff and jitter (2 s → 30 s) until the context is cancelled; it never gives up on its own.
• Monitor checks the connection every 10 s and logs MongoDB connection lost / MongoDB connection restored.
• The "Connected to MongoDB" log line reports mongo_auth=disabled or enabled (user=…, authSource=…, source=env|uri) plus the pool sizes. The password is never logged.
• No default password exists in the code.

Releasing

Tag the commit with a semantic version (git tag v1.0.1 && git push --tags); consumers bump the version in their go.mod. A breaking change needs a new major version and the /v2 suffix in the module path.

License

Apache-2.0, see LICENSE.