keepalive

Pluggable Go daemon that periodically touches external services to prevent idle shutdowns, pauses, or cold starts.

The current adapters perform cheap datastore writes for Redis Cloud, Valkey, Aiven, Neon, Supabase, MongoDB Atlas, Couchbase Capella, and similar hosted services.

Successor to the *-keepalive family: one binary, one image, six datastore adapters.

Configuration

By default, keepalive reads the first config file it finds: config.yml, config.yaml, /config.yml, then /config.yaml. One deployment can keep any number of services alive.

# Default interval for every service.
interval: 1m
counter_key: counter

services:
  - adapter: redis
    config:
      url: redis://default@redis-a.example.com:6379
      namespace: keepalive

  - adapter: valkey
    # One service can override the global interval and counter key.
    interval: 30s
    counter_key: valkey-counter
    config:
      url: valkey://default@valkey-a.example.com:6379

  - adapter: postgresql
    config:
      url: postgresql://user:pass@postgres-a.example.com:5432/keepalive?sslmode=require

  - adapter: mysql
    config:
      dsn: user:pass@tcp(mysql-a.example.com:3306)/keepalive

  - adapter: mongodb
    config:
      uri: mongodb+srv://user:pass@mongo-a.example.com
      database: keepalive
      collection: counter

  - adapter: couchbase
    config:
      connection_string: couchbases://couchbase-a.example.com
      username: user
      password: pass
      bucket_name: keepalive
      scope_name: _default
      collection_name: _default

name is optional. When omitted, keepalive generates a name from adapter and the connection host, such as redis-redis-a-example-com. Duplicate generated names get suffixes like redis-redis-a-example-com-2.

interval at the root sets the default schedule for every service and defaults to 1m. interval inside a service overrides that default only for that service. In the example above, every service runs every 1m except valkey, which runs every 30s. Interval values use Go duration syntax, for example 30s, 5m, 1h, 1h30m, or 1.5h. Plain integers are treated as seconds, so 90 means 90s.

counter_key at the root sets the default counter key for every service and defaults to counter. counter_key inside a service overrides that default only for that service. In the example above, every service writes counter except valkey, which writes valkey-counter.

Supported adapters

adapter	Driver	config keys
redis	github.com/redis/go-redis/v9	url, optional namespace
valkey	github.com/valkey-io/valkey-go	url
postgresql	github.com/lib/pq	url
mysql	github.com/go-sql-driver/mysql	dsn
mongodb	go.mongodb.org/mongo-driver/v2	uri, database, collection
couchbase	github.com/couchbase/gocb/v2	connection_string, username, password, bucket_name, scope_name, collection_name, optional ready_timeout, optional bucket_ram_quota_mb

Quick start (Compose)

cp config.example.yml config.yml
docker compose up -d --build

Quick start (Docker)

docker build -t keepalive:local .
docker run -d --name keepalive --restart unless-stopped \
  -v "$PWD/config.yml:/config.yml:ro" \
  keepalive:local

If you prefer to mount the config into a working directory instead of the container root, set the container working directory and mount the file there:

docker run -d --name keepalive --restart unless-stopped \
  --workdir /workspace \
  -v "$PWD/config.yml:/workspace/config.yml:ro" \
  keepalive:local

Quick start (local)

git clone https://github.com/tiennm99/keepalive
cd keepalive
cp config.example.yml config.yml
go run .

How it works

On startup each adapter initializes the minimum resource it owns, then every tick performs the cheapest write that proves the cluster is alive. counter_key selects the key/doc ID and defaults to counter.

• Redis — initialize with SETNX key 0, then INCR key. When namespace is empty, the key is counter; when namespace: keepalive, the key is keepalive:counter.
• Valkey — initialize with SETNX key 0, then INCR key
• PostgreSQL — CREATE TABLE IF NOT EXISTS keepalive, seed key, then UPDATE ... RETURNING
• MySQL — CREATE TABLE IF NOT EXISTS keepalive, seed key, then UPDATE + SELECT
• MongoDB — upsert {_id: key, count: 0} on connect, then FindOneAndUpdate({_id: key}, {$inc: {count: 1}}, upsert)
• Couchbase — optionally create the bucket when bucket_ram_quota_mb is set, create configured scope/collection when missing, insert key = 0 if missing, then GET key -> ++ -> UPSERT key

Each configured service starts independently. If one service cannot connect, it logs the error and retries without stopping other services in the same deployment.

For hosted Couchbase/Capella clusters, ready_timeout defaults to 30s. If Couchbase reports CONNECTION_ERROR, check the connection string, bucket name, database user permissions, and Capella allowed IP/network access.

Adding a new adapter

1. Create adapter/<name>.go.
2. Implement the Adapter interface in adapter/adapter.go (Connect, Increment, Close).
3. Register the factory in init():

   func init() { Registry["<name>"] = func(cfg Config) (Adapter, error) { return &myAdapter{}, nil } }
   

4. Add an import _ "your driver" if needed, and the adapter config keys to config.example.yml and the table above.

Migrated from

This repo replaces six single-datastore repos. All are archived with a pointer here:

• redis-keepalive
• valkey-keepalive
• postgresql-keepalive
• mysql-keepalive
• mongodb-keepalive
• couchbase-keepalive

License

Apache-2.0 — see LICENSE.