Configuration

Every runtime setting is available as a CLI flag and an environment variable. Flags take precedence when both are set. Defaults apply when neither is set.

Durations use Go's time.ParseDuration syntax (500ms, 5s, 1m, 1h).

Server

Flag	Environment	Default	Description
--listen	IMGSRV_LISTEN	:8080	HTTP listen address for the public API.
--node-name	IMGSRV_NODE_NAME	empty	Prefix used in background worker IDs.
--shutdown-timeout	IMGSRV_SHUTDOWN_TIMEOUT	10s	Graceful HTTP shutdown deadline.

Logging

Flag	Environment	Default	Description
--log-format	IMGSRV_LOG_FORMAT	text	Log encoding. One of text, json.
--verbosity	IMGSRV_VERBOSITY	info	Minimum log level. One of debug, info, warn, error.

Metrics

Flag	Environment	Default	Description
--metrics-listen	IMGSRV_METRICS_LISTEN	127.0.0.1:9464	Metrics HTTP listen address. Empty disables the metrics listener.
--metrics-path	IMGSRV_METRICS_PATH	/metrics	HTTP path that serves Prometheus metrics.

PostgreSQL

Flag	Environment	Default	Description
--postgres-url	IMGSRV_POSTGRES_URL	empty	PostgreSQL connection URL. Empty skips database startup; routes whose backing adapter is unavailable return 503.

S3-compatible object storage

Flag	Environment	Default	Description
--s3-endpoint	IMGSRV_S3_ENDPOINT	empty	S3-compatible endpoint host and port without a URL scheme.
--s3-bucket	IMGSRV_S3_BUCKET	empty	Bucket used for staging and CAS objects.
--s3-access-key-id	IMGSRV_S3_ACCESS_KEY_ID	empty	S3 access key ID.
--s3-secret-access-key	IMGSRV_S3_SECRET_ACCESS_KEY	empty	S3 secret access key.
--s3-session-token	IMGSRV_S3_SESSION_TOKEN	empty	Optional temporary credential session token.
--s3-region	IMGSRV_S3_REGION	empty	Optional region.
--s3-use-tls	IMGSRV_S3_USE_TLS	false	Use HTTPS for the S3-compatible endpoint.
--s3-path-style	IMGSRV_S3_PATH_STYLE	false	Use path-style bucket addressing instead of virtual-hosted-style.

Uploads

Flag	Environment	Default	Description
--upload-ttl	IMGSRV_UPLOAD_TTL	24h	Lifetime of a new upload session before it expires if not completed.

CAS promotion worker

The CAS promotion worker verifies completed upload sessions and records the resulting CAS blobs. It is disabled by default.

Flag	Environment	Default	Description
--cas-promotion-enabled	IMGSRV_CAS_PROMOTION_ENABLED	false	Run the in-process CAS promotion worker.
--cas-promotion-poll-interval	IMGSRV_CAS_PROMOTION_POLL_INTERVAL	5s	Idle poll interval.
--cas-promotion-error-backoff	IMGSRV_CAS_PROMOTION_ERROR_BACKOFF	5s	Initial delay after a failed promotion.
--cas-promotion-error-backoff-max	IMGSRV_CAS_PROMOTION_ERROR_BACKOFF_MAX	1m	Maximum delay between retries.
--cas-promotion-circuit-breaker-failures	IMGSRV_CAS_PROMOTION_CIRCUIT_BREAKER_FAILURES	10	Consecutive failures that open the circuit breaker.
--cas-promotion-circuit-breaker-cooldown	IMGSRV_CAS_PROMOTION_CIRCUIT_BREAKER_COOLDOWN	1m	Cooldown applied while the circuit breaker is open.

Build metadata

--version prints release version, commit, and build date, then exits. It has no environment-variable equivalent.