Configuration Reference: [Product name] [version]

Complete list of the settings that control [Product name], how they are loaded and how they are validated. Based on common industry practice for configuration reference documentation. Replace every [bracketed] value and every row marked Example.

1. Sources and precedence

[Product name] reads configuration from four sources. When the same setting is defined in more than one place, the source higher in this list wins:

To see the effective value and where it came from, run [app] config show --origin. Secrets are masked in the output.

2. File location and format

The first file found in this order is used; others are ignored:

1. The path in --config or APP_CONFIG.
2. ./app.yaml in the working directory.
3. /etc/app/app.yaml (Windows: %ProgramData%\App\app.yaml).

YAML 1.2 and TOML 1.0 are supported; the format is chosen from the file extension. Unknown keys are rejected so that typos are not silently ignored. A complete example with defaults:

schema_version: 3
server:
  host: 0.0.0.0
  port: 8080
  request_timeout: 30s
database:
  url: ${DATABASE_URL}
  max_connections: 20
cache:
  enabled: true
  ttl: 5m
logging:
  level: info
  format: json

${NAME} is replaced with the value of environment variable NAME at load time; a missing variable is a validation error.

3. Value types

4. Settings

4.1 server

4.2 database

4.3 cache

4.4 logging

5. Changes at runtime

Settings marked with a reload flag in config show --origin can be changed without restarting: edit the file and send SIGHUP or call POST /admin/reload. Currently reloadable: logging.level, cache.ttl, server.request_timeout. All other changes need a restart.

6. Deprecated and removed settings

7. Validation

Configuration is validated at startup and on every reload. An invalid configuration stops startup; an invalid reload is rejected and the running configuration stays in place. Run the same checks before deploying:

app config validate --config ./app.yaml

Checks performed:

• Every key is known for the declared schema_version.
• Every value has the right type and is inside its allowed range.
• Required settings without defaults are present.
• Referenced environment variables exist.
• Cross-field rules hold, for example $\text{database.max\_connections} \times \text{instances} \le$ the database server's connection limit (checked when --instances is given).

Example error output (exit status 2):

app.yaml:7:20 database.max_connections: 900 is above the maximum of 500
app.yaml:12:10 logging.level: "verbose" is not one of debug, info, warn, error

8. Related documents

• [Installation Guide]: where the file is created during setup.
• [Administrator Guide]: recommended production values and tuning.
• [Changelog]: settings added, changed or deprecated per release.

Standard and licence note

Based on common industry practice for configuration reference documentation, including layered precedence of flags, environment variables, files and defaults. Template licence: MIT.