Structured logging

Windrunner uses Spring Boot's structured logging support. You can write one JSON object per log line to standard output and let your container or host log collector forward it to Elastic, Datadog, Loki, Splunk, OpenTelemetry, or another observability platform.

The recommended production format is Elastic Common Schema (ECS). It uses standard fields for timestamps, log levels, services, processes, and errors, which makes the same output useful across different logging agents.

Enable JSON logs

Set the console format to ecs in application.properties:

logging.structured.format.console=ecs
logging.structured.ecs.service.name=windrunner
logging.structured.ecs.service.environment=production

The application writes JSON logs to standard output. In a container deployment, collect standard output with your normal container logging driver or agent.

For a deployment that is configured only with environment variables, use Spring Boot's relaxed binding names:

LOGGING_STRUCTURED_FORMAT_CONSOLE=ecs
LOGGING_STRUCTURED_ECS_SERVICE_NAME=windrunner
LOGGING_STRUCTURED_ECS_SERVICE_ENVIRONMENT=production

Restart the application after changing these values.

Use normal text logs

Leave logging.structured.format.console unset to use Spring Boot's normal human-readable console format. This is usually more convenient for local development.

You can also choose another built-in JSON format when a collector expects it:

Value	Format	Use when
ecs	Elastic Common Schema	Recommended default for general observability.
logstash	Logstash JSON	A Logstash pipeline expects Logstash field names.
gelf	Graylog Extended Log Format	Logs are sent directly to a Graylog pipeline.

For example:

logging.structured.format.console=logstash

File output

If the deployment writes logs to a file, configure the file format separately:

logging.structured.format.file=ecs

The environment-variable form is:

LOGGING_STRUCTURED_FORMAT_FILE=ecs

Most container deployments should keep logs on standard output instead of writing application log files inside the container.

Docker Compose

The tracked Compose file does not need to be edited. Create a local docker-compose.override.yml next to docker-compose.yml when you want JSON logs for a Compose deployment:

services:
  app:
    environment:
      LOGGING_STRUCTURED_FORMAT_CONSOLE: ecs
      LOGGING_STRUCTURED_ECS_SERVICE_NAME: windrunner
      LOGGING_STRUCTURED_ECS_SERVICE_ENVIRONMENT: production

Start the deployment normally:

docker compose up -d

Then inspect one JSON event with:

docker compose logs --no-log-prefix app | head -n 1

See the official Spring Boot structured logging reference for the complete list of supported formats and customization properties.