Observability

Structured output

Use --json for machine-readable sync reports:

ocync sync -c config.yaml --json

Reports include per-image results and aggregate statistics: blobs transferred, bytes moved, mounts performed, cache hits, and errors.

Abbreviated example:

{
  "run_id": "019713a2-...",
  "images": [
    {
      "image_id": "019713a2-...",
      "source": "cgr.dev/chainguard/nginx:latest",
      "target": "123456789012.dkr.ecr.us-east-1.amazonaws.com/nginx:latest",
      "status": "synced",
      "bytes_transferred": 31457280,
      "blob_stats": { "transferred": 3, "skipped": 1, "mounted": 2 },
      "duration": { "secs": 4, "nanos": 210000000 }
    }
  ],
  "stats": {
    "images_synced": 1,
    "images_skipped": 0,
    "images_failed": 0,
    "blobs_transferred": 3,
    "blobs_skipped": 1,
    "blobs_mounted": 2,
    "bytes_transferred": 31457280,
    "discovery_cache_hits": 0,
    "discovery_cache_misses": 1,
    "discovery_head_failures": 0,
    "discovery_target_stale": 0
  },
  "duration": { "secs": 4, "nanos": 210000000 }
}

Progress indicators

ocync auto-detects the output environment:

• TTY: real-time progress bars with per-image and aggregate stats
• Non-TTY / CI: periodic heartbeat lines with summary counts

Disable all progress output with --quiet.

Logging

Control verbosity with -v flags:

Log format

# Human-readable (default)
ocync sync -c config.yaml -vv

# JSON (auto-detected in Kubernetes, or explicit)
ocync sync -c config.yaml -vv --log-format json

JSON log format is auto-detected when running inside Kubernetes (via KUBERNETES_SERVICE_HOST environment variable).

Override with the RUST_LOG environment variable for fine-grained filter directives.

Health endpoints

In watch mode, ocync exposes HTTP health endpoints:

Configure the port via --health-port (default 8080) or in Helm values:

mode: watch
watch:
  healthPort: 8080

See CLI reference for all watch flags including --interval and --json.