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🔥 Real-time terminal dashboard for Caddy servers, with built-in FrankenPHP support

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# Ember - Real-time monitoring for Caddy

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Monitor your Caddy server in real time: per-host traffic, latency percentiles, status codes, and more. When FrankenPHP is detected, unlock per-thread introspection, worker management, and memory tracking. It is officially recommended by [FrankenPHP](https://frankenphp.dev/).

![ember banner](https://github.com/alexandre-daubois/ember/blob/main/assets/banner.webp?raw=true)

## Why Ember?

Caddy exposes rich metrics through its admin API and Prometheus endpoint, but reading raw Prometheus text or setting up a full Grafana stack just to glance at traffic is heavy. Ember gives you a zero-config, read-only terminal dashboard that connects to Caddy's admin API and works out of the box. No extra infrastructure, no YAML to write: just `ember` and you're monitoring.

![ember screenshot](https://github.com/alexandre-daubois/ember/blob/main/assets/ember.gif?raw=true)

## Features

**Caddy Monitoring**

- Per-host traffic table with RPS, average latency, status codes, and sparklines
- Latency percentiles (P50, P90, P95, P99) and Time-to-First-Byte per host
- Sorting, filtering, and full-screen ASCII graphs (CPU, RPS, RSS)
- Config Inspector tab: browse the live Caddy JSON config as a collapsible tree
- Certificates tab: TLS certificate monitoring with expiry tracking, color-coded warnings, and likely auto-renewal indication
- Upstreams tab: reverse proxy upstream health monitoring with per-upstream status, auto-detected when `reverse_proxy` is configured
- Logs tab: live access and runtime log streaming in a single view, with a sidepanel tree (Runtime, Access, per-host children, [By Route](docs/logs.md#by-route-view) aggregation) and a free-text filter. Zero-config: Ember hot-registers two transient sinks in Caddy via the admin API (`__ember__` for access logs, `__ember_runtime__` for everything else) and receives logs over TCP with no Caddyfile changes, or streams them directly from standard input (stdin)
- Automatic Caddy restart detection

**FrankenPHP Introspection**

- Per-thread state, method, URI, duration, and memory tracking (method, URI, duration, memory, and request count require FrankenPHP 1.12.2+)
- Worker management with queue depth and crash monitoring
- Graphs for queue depth and busy threads
- Automatic detection and recovery when FrankenPHP starts or stops

**Integration & Operations**

- Prometheus metrics export (`/metrics`) with optional basic auth and health endpoint (`/healthz`)
- [Multi-instance scraping](docs/multi-instance.md) in `--daemon`, `--json`, `status`, `wait`, `init`, and `diff` modes: a single Ember process aggregates several Caddy instances behind one Prometheus endpoint with an `ember_instance` label, per-instance TLS material, and per-instance polling cadence
- Self-observability: `ember_*` metrics (build info, per-stage scrape totals, errors, durations, last success) so you can monitor the monitor
- Daemon mode for headless operation, with error throttling and TLS certificate reload via SIGHUP
- JSON output mode for scripting, with `--once` for single snapshots
- Quick health check: `ember status` (text or `--json`) for a one-line Caddy summary
- Readiness gate: `ember wait` blocks until Caddy is up (`-q` for silent scripting; supports repeated `--addr` with `--any` for first-ready semantics)
- Deployment validation: `ember diff before.json after.json` compares snapshots (single-instance JSON or multi-instance JSONL, with one diff block per instance)
- Zero-config setup: `ember init` checks Caddy, enables metrics, and warns about missing host matchers
- Unix socket support for Caddy admin APIs configured with `admin unix//path`
- TLS and mTLS support for secured Caddy admin APIs
- Environment variable configuration (`EMBER_ADDR`, `EMBER_EXPOSE`, `EMBER_LOG_LISTEN`, `EMBER_STDIN_LOGS`, ...) for container deployments
- [Config file](docs/cli-reference.md#config-file) (`.ember.toml`): declare a fleet of named endpoints once instead of repeating `--addr`. The TUI connects to one (a saved `default` or an interactive picker); `--daemon`, `--json`, `status`, `wait`, and `init` fan out across all of them. `ember config use <name>` sets the TUI default
- `NO_COLOR` env var support ([no-color.org](https://no-color.org/))
- Lightweight: ~15 MB RSS, ~0.3 ms per poll cycle with 100 threads and 10 hosts ([benchmarks](internal/app/daemon_bench_test.go))
- Cross-platform binaries (Linux, macOS, Windows), Homebrew tap, and Docker image

## Install

```bash
curl -fsSL https://raw.githubusercontent.com/alexandre-daubois/ember/main/install.sh | sh
```

Or with Homebrew:

```bash
brew install alexandre-daubois/tap/ember
```

> **macOS:** if Gatekeeper blocks the binary on first run, remove the quarantine attribute:
> `xattr -d com.apple.quarantine $(which ember)`, or allow it manually in
> System Settings → Privacy & Security.

Or with Go:

```bash
go install github.com/alexandre-daubois/ember/cmd/ember@latest
```

Or with Docker (runs in daemon mode by default, see [Docker docs](docs/docker.md)):

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

The image is also mirrored on GHCR as `ghcr.io/alexandre-daubois/ember`.

You can also download the latest binaries from the [release page](https://github.com/alexandre-daubois/ember/releases). If you use this method, don't forget to check for updates regularly!

## Quick Start

Make sure Caddy is running with the admin API enabled (it is by default). Then:

```bash
ember init
```

This checks your Caddy setup and enables metrics via the admin API if needed (no restart required). Once ready:

```bash
ember
```

Ember connects to the Caddy admin API and auto-detects FrankenPHP if present.

For a quick one-line health check:

```bash
ember status
```

## How It Works

Ember polls the Caddy admin API and Prometheus metrics endpoint at a regular interval (default: 1s), computes deltas and derived metrics (RPS, percentiles, error rates), and renders them through one of several output modes: an interactive [Bubble Tea](https://github.com/charmbracelet/bubbletea) TUI (default), streaming JSONL, a headless daemon with Prometheus export, or a one-shot `status` command.

## Plugins (experimental)

Ember supports a plugin system that lets third-party developers add custom tabs for visualizing metrics from additional Caddy modules (e.g., rate limiters, WAF modules, custom middleware). Plugins are compiled into the binary using Go's blank import pattern, the same approach used by Caddy itself.

Building a custom Ember binary with plugins is simple:

```go
import (
    "github.com/alexandre-daubois/ember"
    _ "github.com/myorg/ember-myplugin"
)

func main() { ember.Run() }
```

Plugins can provide multiple tabs, subscribe to core metrics, conditionally hide their tabs, and reuse Ember's Prometheus parser via the `pkg/metrics` package.

See the [Plugin Development Guide](docs/plugins.md) for details on building and integrating plugins.

The plugin API is still evolving: feedback is very welcome. If something does not fit your use case or you wish an interface exposed more (or less), please [open an issue](https://github.com/alexandre-daubois/ember/issues) and tell us what you are trying to build.

## Documentation

Full documentation is available in the [docs/](docs/index.md) directory:

- [Getting Started](docs/getting-started.md): Install and first run
- [Caddy Configuration](docs/caddy-configuration.md): Caddyfile requirements
- [Caddy Dashboard](docs/caddy-dashboard.md): Per-host traffic and latency
- [FrankenPHP Dashboard](docs/frankenphp-dashboard.md): Thread introspection and workers
- [Logs](docs/logs.md): Live tailing of access and runtime logs, per-host drill-down, and a By Route view that aggregates traffic by normalized URI pattern, with per-route latency and FrankenPHP memory stats
- [CLI Reference](docs/cli-reference.md): Flags, keybindings, shell completions
- [JSON Output](docs/json-output.md): Streaming JSONL for scripting
- [Prometheus Export](docs/prometheus-export.md): Metrics, health checks, daemon mode
- [Docker](docs/docker.md): Container usage
- [Agent Skills](docs/skills.md): Skills for AI coding agents
- [Plugins](docs/plugins.md): Building custom plugins for Ember (experimental)
- [Troubleshooting](docs/troubleshooting.md): Common issues and solutions

## Contributing

See [CONTRIBUTING.md](CONTRIBUTING.md) for development setup, architecture overview, and guidelines.

## License

MIT

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