Configuration

Watt is configured with a configuration file. It supports the use of environment variables as setting values with environment variable placeholders.

Configuration Files

Watt automatically detects and loads configuration files found in the current working directory with the file names listed here.

Alternatively, you can use the --config option to specify a configuration file path for most platformatic runtime CLI commands. The configuration examples in this reference use the JSON format.

Supported File Formats

For detailed information on supported file formats and extensions, please visit our Supported File Formats and Extensions page.

Settings

Configuration settings containing sensitive data should be set using environment variable placeholders.

info

The autoload and services settings can be used together, but at least one of them must be provided. When the configuration file is parsed, autoload configuration is translated into services configuration.

autoload

The autoload configuration is intended to be used with monorepo applications. autoload is an object with the following settings:

• path (required, string) - The path to a directory containing the microservices to load. In a traditional monorepo application, this directory is typically named packages.
• exclude (array of strings) - Child directories inside path that should not be processed.
• mappings (object) - Each microservice is given an ID and is expected to have a Platformatic configuration file. By default, the ID is the microservice's directory name, and the configuration file is expected to be a well-known Platformatic configuration file. mappings can be used to override these default values.
  • id (required, string) - The overridden ID. This becomes the new microservice ID.
  • **config (string) - The overridden configuration file. name. This is the file that will be used when starting the microservice.
  • useHttp (boolean) - The service will be started on a random HTTP port on 127.0.0.1, and exposed to the other services via that port and on default, it is set to false.
  • workers (number) - The number of workers to start for this service. If the service is the entrypoint or if the runtime is running in development mode this value is ignored and hardcoded to 1.
  • health (object): Configures the health check for each worker of the service. It supports all the properties also supported in the runtime health property. The values specified here overrides the values specified in the runtime.

preload

The preload configuration is intended to be used to register Application Performance Monitoring (APM) agents. preload should contain a path pointing to a CommonJS or ES module that is loaded at the start of the app worker thread.

services

services is an array of objects that defines the microservices managed by the runtime. Each service object supports the following settings:

• id (required, string) - A unique identifier for the microservice. When working with the Platformatic Composer, this value corresponds to the id property of each object in the services section of the config file. When working with client objects, this corresponds to the optional serviceId property or the name field in the client's package.json file if a serviceId is not explicitly provided.
• path (required, string) - The path to the directory containing the microservice. It can be omitted if url is provided.
• url (required, string) - The URL of the service, if it is a remote service. It can be omitted if path is provided.
• config (string) - The configuration file used to start the microservice.
• useHttp (boolean) - The service will be started on a random HTTP port on 127.0.0.1, and exposed to the other services via that port, on default it is set to false. Set it to true if you are using @fastify/express.
• workers (number) - The number of workers to start for this service. If the service is the entrypoint or if the runtime is running in development mode this value is ignored and hardcoded to 1.
• health (object): Configures the health check for each worker of the service. It supports all the properties also supported in the runtime health property. The values specified here overrides the values specified in the runtime.

If this property is present, then the services will not be reordered according to the getBootstrapDependencies function and they will be started in the order they are defined in the configuration file.

entrypoint

The Platformatic Runtime's entrypoint is a microservice that is exposed publicly. This value must be the ID of a service defined via the autoload or services configuration.

workers

The default number of workers to start per each service. It can be overriden at service level.

This value is hardcoded to 1 if the runtime is running in development mode or when applying it to the entrypoint.

gracefulShutdown

Configures the amount of milliseconds to wait before forcefully killing a service or the runtime.

The object supports the following settings:

• service (number) - The graceful shutdown timeout for a service.
• runtime (number) - The graceful shutdown timeout for the entire runtime.

For both the settings the default is 10000 (ten seconds).

watch

An optional boolean, set to default false, indicating if hot reloading should be enabled for the runtime. If this value is set to false, it will disable hot reloading for any microservices managed by the runtime. If this value is true, then hot reloading for individual microservices is managed by the configuration of that microservice.

Note that watch should be enabled for each individual service in the runtime.

warning

While hot reloading is useful for development, it is not recommended for use in production.

startTimeout

The number of milliseconds to wait before considering a service as failed to start. Default: 30000.

restartOnError

The number of milliseconds to wait before attempting to restart a service that unexpectedly exit.

If not specified or set to true, the default value is 5000, set to 0 or false to disable.

health

Configures the health check for each worker. This is enabled only if restartOnError is greater than zero.

The object supports the following settings:

• enabled (boolean): If to enable the health check. Default: true.
• interval (number): The interval between checks in milliseconds. Default: 30000.
• gracePeriod: How long after the service started before starting to perform health checks. Default: 30000.
• maxUnhealthyChecks: The number of consecutive failed checks before killing the worker. Default: 1.
• maxELU: The maximum allowed Event Loop Utilization. The value must be a percentage between 0 and 1. Default: 0.95.
• maxHeapUsed: The maximum allowed memory utilization. The value must be a percentage between 0 and 1. Default: 0.95.
• maxHeapTotal: The maximum allowed memory allocatable by the process. The value must be an amount in bytes. Default: 4G.

telemetry

Open Telemetry is optionally supported with these settings:

• serviceName (required, string) — Name of the service as will be reported in open telemetry. In the runtime case, the name of the services as reported in traces is ${serviceName}-${serviceId}, where serviceId is the id of the service in the runtime.
• version (string) — Optional version (free form)
• skip (array). Optional list of operations to skip when exporting telemetry defined object with properties:
  • method: GET, POST, PUT, DELETE, PATCH, HEAD, OPTIONS, TRACE
  • path. e.g.: /documentation/json
• exporter (object or array) — Exporter configuration. If not defined, the exporter defaults to console. If an array of objects is configured, every object must be a valid exporter object. The exporter object has the following properties:
  • type (string) — Exporter type. Supported values are console, otlp, zipkin and memory (default: console). memory is only supported for testing purposes.
  • options (object) — These options are supported:
    • url (string) — The URL to send the telemetry to. Required for otlp exporter. This has no effect on console and memory exporters.
    • headers (object) — Optional headers to send with the telemetry. This has no effect on console and memory exporters.

basePath

The base path for the Platformatic Runtime. Set it when your application is deployed under a subpath, for example, /api. The runtime will automatically strip the base path from the incoming requests.

important

OTLP traces can be consumed by different solutions, like Jaeger. See the full list here.

Example JSON object

{
  "telemetry": {
    "serviceName": "test-service",
    "exporter": {
      "type": "otlp",
      "options": {
        "url": "http://localhost:4318/v1/traces"
      }
    }
  }
}

server

This configures the Platformatic Runtime entrypoint server.

If the entrypoint has also a server configured, then the runtime settings override the service settings.

An object with the following settings:

• hostname — Hostname where Platformatic Service server will listen for connections.
• port — Port where Platformatic Service server will listen for connections.
• http2 (boolean) — Enables HTTP/2 support. Default: false.
• https (object) - Configuration for HTTPS supporting the following options. Requires https.
  • allowHTTP1 (boolean) - If true, the server will also accept HTTP/1.1 connections when http2 is enabled. Default: false.
  • key (required, string, object, or array) - If key is a string, it specifies the private key to be used. If key is an object, it must have a path property specifying the private key file. Multiple keys are supported by passing an array of keys.
  • cert (required, string, object, or array) - If cert is a string, it specifies the certificate to be used. If cert is an object, it must have a path property specifying the certificate file. Multiple certificates are supported by passing an array of keys.

logger

This configures the Platformatic Runtime logger.

See the logger configuration for more information.

undici

This configures the undici global Dispatcher. Allowing to configure the options in the agent as well as interceptors.

Example JSON object

{
  "undici": {
    "keepAliveTimeout": 1000,
    "keepAliveMaxTimeout": 1000,
    "interceptors": [
      {
        "module": "undici-oidc-interceptor",
        "options": {
          "clientId": "{PLT_CLIENT_ID}",
          "clientSecret": "{PLT_CLIENT_SECRET}",
          "idpTokenUrl": "{PLT_IDP_TOKEN_URL}",
          "origins": ["{PLT_EXTERNAL_SERVICE}"]
        }
      }
    ]
  }
}

It's important to note that IDP stands for Identity Provider, and its token url is the URL that will be called to generate a new token.

serviceTimeout

The number of milliseconds to wait when invoking another service using the its plt.local before considering the request timed out. Default: 300000 (5 minutes).

metrics

This configures the Platformatic Runtime Prometheus server. The Prometheus server exposes aggregated metrics from the Platformatic Runtime services.

• hostname (string). The hostname where the Prometheus server will be listening. Default: 0.0.0.0.
• port (number). The port where the Prometheus server will be listening. Default: 9090.
• endpoint (string). The endpoint where the Prometheus server will be listening. Default: /metrics.
• auth (object). Optional configuration for the Prometheus server authentication.
  • username (string). The username for the Prometheus server authentication.
  • password (string). The password for the Prometheus server authentication.

managementApi

Warning: Experimental. The feature is not subject to semantic versioning rules. Non-backward compatible changes or removal may occur in any future release. Use of the feature is not recommended in production environments.

An optional object that configures the Platformatic Management Api. If this object is not provided, the Platformatic Management Api will not be started. If enabled, it will listen to UNIX Socket/Windows named pipe located at platformatic/pids/<PID> inside the OS temporary folder.

• logs (object). Optional configuration for the runtime logs.
  • maxSize (number). Maximum size of the logs that will be stored in the file system in MB. Default: 200. Minimum: 5.

Setting and Using ENV placeholders

The value for any configuration setting can be replaced with an environment variable by adding a placeholder in the configuration file, for example {PLT_ENTRYPOINT}.

If an .env file exists it will automatically be loaded by Platformatic using dotenv. For example:

.env

PLT_ENTRYPOINT=service

The .env file must be located in the same folder as the Platformatic configuration file or in the current working directory.

Environment variables can also be set directly on the command line, for example:

PLT_ENTRYPOINT=service npx platformatic runtime

note

Learn how to set and use environment variable placeholders documentation.

PLT_ROOT

The {PLT_ROOT} placeholder is automatically set to the directory containing the configuration file, so it can be used to configure relative paths. See our documentation to learn more on PLT_ROOT placeholders.

Issues

If you run into a bug or have a suggestion for improvement, please raise an issue on GitHub or join our Discord feedback channel.