ember-production

name

ember-production

description

Deploy Ember in production environments with daemon mode, Prometheus metrics export, and Docker. Use this skill whenever someone asks about running ember headless, exporting Prometheus metrics, setting up ember in Docker or docker-compose, integrating ember with Grafana, configuring health checks, or any production deployment of Caddy/FrankenPHP monitoring. For JSON output, scripting, and CI pipelines, see the ember-json skill instead.

Ember Production Deployment

This skill covers running Ember in production: headless daemon mode, Prometheus metrics export, and Docker deployment. For JSON output, scripting, CI integration, and ember diff/ember wait, see the ember-json skill.

Daemon Mode

The --daemon flag disables the TUI and runs Ember as a background metrics collector. It requires --expose to serve a Prometheus endpoint.

ember --expose :9191 --daemon

This starts an HTTP server with:

• /metrics: Prometheus text format (v0.0.4)
• /healthz: JSON health check

Combined with the TUI

You can also keep the TUI while exposing metrics:

ember --expose :9191

Structured logging

For log aggregation (ELK, Loki, etc.), use JSON log format:

ember --expose :9191 --daemon --log-format json

Logs go to stderr. When Ember loses Caddy connectivity, it logs one error immediately then suppresses duplicates for 30 seconds to avoid flooding. A "fetch recovered" message is logged when connectivity returns.

Signals (Unix only)

Signal	Effect
SIGUSR1	Dump full state snapshot to stderr as JSON (for debugging)
SIGHUP	Reload TLS certificates from disk without restarting

# Debug dump
kill -USR1 $(pgrep ember)

# Rotate certificates
kill -HUP $(pgrep ember)

Prometheus Metrics

Exported metrics

Caddy host metrics:

Metric	Type	Labels
ember_host_rps	gauge	host
ember_host_latency_avg_milliseconds	gauge	host
ember_host_latency_milliseconds	gauge	host, quantile (0.5, 0.9, 0.95, 0.99)
ember_host_inflight	gauge	host
ember_host_status_rate	gauge	host, class (2xx, 3xx, 4xx, 5xx)
ember_host_error_rate	gauge	host

FrankenPHP metrics:

Metric	Type	Labels
frankenphp_threads_total	gauge	state (busy, idle, other)
frankenphp_thread_memory_bytes	gauge	index
frankenphp_worker_crashes_total	counter	worker
frankenphp_worker_restarts_total	counter	worker
frankenphp_worker_queue_depth	gauge	worker
frankenphp_worker_requests_total	counter	worker
frankenphp_request_duration_milliseconds	gauge	quantile (0.5, 0.95, 0.99)

Process metrics:

Metric	Type
process_cpu_percent	gauge
process_rss_bytes	gauge

Custom metric prefix

Add a prefix to all metric names to avoid collisions:

ember --expose :9191 --metrics-prefix myapp

This turns ember_host_rps into myapp_ember_host_rps, frankenphp_threads_total into myapp_frankenphp_threads_total, etc.

Authentication

Protect the metrics endpoint with HTTP Basic Auth:

ember --expose :9191 --daemon --metrics-auth admin:secret

Prefer the environment variable to avoid exposing credentials in ps output:

export EMBER_METRICS_AUTH=admin:secret
ember --expose :9191 --daemon

Prometheus scrape configuration

scrape_configs:
  - job_name: ember
    scrape_interval: 5s
    static_configs:
      - targets: ["localhost:9191"]

With authentication:

scrape_configs:
  - job_name: ember
    scrape_interval: 5s
    basic_auth:
      username: admin
      password: secret
    static_configs:
      - targets: ["localhost:9191"]

Health endpoint

GET /healthz returns JSON:

• 200 OK: {"status": "ok", "last_fetch": "...", "age_seconds": 1.2}, data is fresh
• 503: {"status": "stale", ...}, data older than 3x the polling interval (minimum 5s)
• 503: {"status": "no data yet"}, no data collected yet

Use /healthz as a Kubernetes liveness probe to detect when Ember loses contact with Caddy.

Docker Deployment

The Ember image is published to Docker Hub as alexandredaubois/ember and mirrored on GHCR as ghcr.io/alexandre-daubois/ember. It is built from scratch: no OS, no shell, just the static binary and CA certificates.

Default behavior: --daemon --expose :9191

Host network (simplest)

docker run --rm --network host alexandredaubois/ember

Custom address

docker run --rm alexandredaubois/ember \
  --daemon --expose :9191 --addr http://caddy:2019

Docker Compose (sidecar pattern)

services:
  caddy:
    image: caddy:latest
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./Caddyfile:/etc/caddy/Caddyfile

  ember:
    image: alexandredaubois/ember
    network_mode: "service:caddy"
    depends_on:
      - caddy

With network_mode: "service:caddy", Ember shares Caddy's network namespace and can reach localhost:2019 directly.

Custom flags in Docker

Override the default CMD by appending flags:

docker run --rm --network host alexandredaubois/ember \
  --daemon --expose :9191 --interval 2s --metrics-prefix myapp

The image has no shell: use docker logs to read Ember's stderr output.

Environment Variables

All main flags have environment variable equivalents, convenient for containers where flags are less practical:

Variable	Flag
EMBER_ADDR	--addr
EMBER_INTERVAL	--interval
EMBER_EXPOSE	--expose
EMBER_METRICS_PREFIX	--metrics-prefix
EMBER_METRICS_AUTH	--metrics-auth

EMBER_METRICS_AUTH is recommended over the flag to avoid leaking credentials in ps output.