Configuration

AnyCable uses anyway_config gem for configuration; thus it is possible to set configuration parameters through environment vars, config/anycable.yml file or secrets.yml when using Rails.

You can also pass configuration variables to CLI as options, e.g.:

$ bundle exec anycable --rpc-host 0.0.0.0:50120 \
                       --redis-channel my_redis_channel \
                       --log-level debug

NOTE: CLI options take precedence over parameters from other sources (files, env).

Primary settings

Here is the list of the most commonly used configuration parameters and the way you can provide them:

in Ruby code using parameter name (e.g. AnyCable.config.rpc_host = "127.0.0.0:42421")
in config/anycable.yml* or secrets.yml using the parameter name
through environment variable
through a CLI option.

rpc_host (ANYCABLE_RPC_HOST, --rpc-host)

Local address to run gRPC server on (default: "[::]:50051", deprecated, will be changed to "127.0.0.1:50051" in future versions).

rpc_tls_cert (ANYCABLE_RPC_TLS_CERT, --rpc-tls-cert) and rpc_tls_key (ANYCABLE_RPC_TLS_KEY, --rpc-tls-key)

Specify file paths or contents for TLS certificate and private key for gRPC server.

broadcast_adapter (ANYCABLE_BROADCAST_ADAPTER, --broadcast-adapter)

Broadcast adapter to use. Available options out-of-the-box: redis (default), nats, http.

nats_servers (ANYCABLE_NATS_SERVERS, --nats-servers)

A comma-separated list of NATS server addresses (default: "nats://localhost:4222").

nats_channel (ANYCABLE_NATS_CHANNEL, --redis-channel)

NATS pus/sub channel for broadcasting (default: "__anycable__").

redis_url (REDIS_URL, ANYCABLE_REDIS_URL, --redis-url)

Redis URL for pub/sub (default: "redis://localhost:6379").

redis_channel (ANYCABLE_REDIS_CHANNEL, --redis-channel)

Redis channel for broadcasting (default: "__anycable__"). When using the redisx adapter, it's used as a name of the Redis stream.

redis_tls_verify (ANYCABLE_REDIS_TLS_VERIFY, --redis-tls-verify)

Whether to validate Redis server TLS certificate if rediss:// protocol is used (default: false).

redis_tls_client_cert_path (ANYCABLE_REDIS_TLS_CLIENT_CERT_PATH, --redis-tls-client_cert-path)

Path to file with client TLS certificate in PEM format if Redis server requires client authentication.

redis_tls_client_key_path (ANYCABLE_REDIS_TLS_CLIENT_KEY_PATH, --redis-tls-client_key-path)

Path to file with private key for client TLS certificate if Redis server requires client authentication.

log_level (ANYCABLE_LOG_LEVEL, --log-level)

Logging level (default: "info").

log_file (ANYCABLE_LOG_FILE, --log-file)

Path to the log file. By default AnyCable logs to STDOUT.

debug (ANYCABLE_DEBUG, --debug)

Shortcut to turn on verbose logging ("debug" log level and gRPC logging on).

For the complete list of configuration parameters see config.rb file.

* You can change the default YML config location path by settings ANYCABLE_CONF env variable.

Presets

AnyCable comes with a few built-in configuration presets for particular deployments environments, such as Fly. The presets are detected and activated automatically

To disable automatic presets activation, provide ANYCABLE_PRESETS=none environment variable (or pass the corresponding option to the CLI: bundle exec anycable --presets=none).

NOTE: Presets do not override explicitly provided configuration values.

Preset: fly

Automatically activated if all of the following environment variables are defined: FLY_APP_NAME, FLY_REGION, FLY_ALLOC_ID.

The preset provide the following defaults:

rpc_host: "0.0.0.0:50051"

If the ANYCABLE_FLY_WS_APP_NAME env variable is provided, the following defaults are configured as well:

nats_servers: "nats://<FLY_REGION>.<ANYCABLE_FLY_WS_APP_NAME>.internal:4222"
http_broadcast_url: "http://<FLY_REGION>.<ANYCABLE_FLY_WS_APP_NAME>.internal:8090/_broadcast"

Concurrency settings

AnyCable gRPC server maintains a pool of worker threads to execute commands. We rely on the grpc gem default pool size, which is equal to 30.

You can configure the pool size via rpc_pool_size parameter (or ANYCABLE_RPC_POOL_SIZE env var).

Increasing pool size makes sense if you have a lot of IO operations in your channels (DB, HTTP, etc.).

NOTE: Make sure the gRPC pool size is aligned with concurrency limits you have in your application, such as database pool size.

IMPORTANT: AnyCable-Go concurrency limit must correlate to the RPC server pool size (read more in AnyCable-Go Configuration).

Redis connections

Redis broadcast adapter uses a single connection to Redis.

Alternative gRPC implementations

AnyCable uses the grpc gem to run its gRPC server by default. The gem heavily relies on native extensions, which may lead to complications during installation (e.g., on Alpine Linux) and compatibility issues with modern Ruby versions.

To be closer to Ruby and depend less on extensions, AnyCable also supports an alternative gRPC implementation—grpc_kit.

You can opt-in to use grpc_kit by setting ANYCABLE_GRPC_IMPL=grpc_kit environment variable for your bundle exec anycable process. You also need to update your Gemfile to include the grpc_kit gem and gRPC-less versions of AnyCable gems:

# For Rails applications
gem "anycable-rails-core", require: ["anycable-rails"]
gem "grpc_kit"

# For non-Rails applications
gem "anycable-core", require: ["anycable"]
gem "grpc_kit"

CLI

HTTP RPC