Service settings as code

A service can carry its settings in a file at the repository root. The same file works for Docker Host and for Services:

miosa.app.yml, miosa.app.yaml or miosa.app.json, and
miosa.json.

railway.json is read as a compatible fallback, so a project imported from Railway needs no edit first.

Rules

Only the fields the file names change. A file with one key leaves every other setting as the project has it. A file is an addition, not a replacement.

The API still validates. The merged settings go through the same validation as a console save, so a file cannot write a value the API would refuse.

The file wins over the console for the fields it names. The console shows which fields came from the file.

Fields

File key	Setting	Applies to
`deploy.start` / `startCommand` / `start_command`	Start command	all
`deploy.preDeploy` / `preDeployCommand`	Pre-deploy command	all
`deploy.healthcheckPath` / `healthcheck_path`	Health check path	web services
`deploy.healthcheckTimeout`	Health check timeout, seconds	web services
`deploy.restartPolicy` / `restartPolicyType`	`always`, `on_failure` or `never`	all
`deploy.maxRetries` / `restartPolicyMaxRetries`	Retries before giving up	all
`deploy.replicas` / `numReplicas`	Replicas	all
`deploy.cron` / `cronSchedule`	Five-field schedule	cron services
`deploy.region`	`us-east`, `us-west` or `us-mia`	all
`deploy.sleep` / `sleepApplication`	Sleep when idle, five minutes by default	web services with a public address
`build_command`	Build command, Railpack builds only	static services
`output_dir`	Directory to serve, relative to the app	static services

variables are read as names; values are not taken from the file.

What the file cannot carry

Keys with no equivalent are reported in the plan and in the console rather than dropped quietly: build.builder, build.dockerfilePath, and anything unknown.