Add Docker setup, add environment vars for each flag

README.md

@@ -37,6 +37,71 @@ Programs are written in Go. No CGO, no external runtime dependencies.
 
 ---
 
+DEPLOYMENT
+
+## Docker
+
+All four binaries are published in a single image: `git.ipng.ch/ipng/nginx-logtail`.
+
+The image is built with a two-stage Dockerfile: a `golang:1.24-alpine` builder produces
+statically-linked, stripped binaries (`CGO_ENABLED=0`, `-trimpath -ldflags="-s -w"`); the final
+stage is `scratch` — no OS, no shell, no runtime dependencies. Each binary is invoked explicitly
+via the container `command`.
+
+### Build and push
+
+```
+docker compose build --push
+```
+
+### Running aggregator + frontend
+
+The `docker-compose.yml` in the repo root runs the aggregator and frontend together. At minimum,
+set `AGGREGATOR_COLLECTORS` to the comma-separated `host:port` list of your collector(s):
+
+```sh
+AGGREGATOR_COLLECTORS=nginx1:9090,nginx2:9090 docker compose up -d
+```
+
+The frontend reaches the aggregator at `aggregator:9091` via Docker's internal DNS. The frontend
+UI is available on port `8080`.
+
+### Environment variables
+
+All flags have environment variable equivalents. CLI flags take precedence over env vars.
+
+**collector** (runs on each nginx host, not in Docker):
+
+| Env var                  | Flag              | Default     |
+|--------------------------|-------------------|-------------|
+| `COLLECTOR_LISTEN`       | `-listen`         | `:9090`     |
+| `COLLECTOR_PROM_LISTEN`  | `-prom-listen`    | `:9100`     |
+| `COLLECTOR_LOGS`         | `-logs`           | —           |
+| `COLLECTOR_LOGS_FILE`    | `-logs-file`      | —           |
+| `COLLECTOR_SOURCE`       | `-source`         | hostname    |
+| `COLLECTOR_V4PREFIX`     | `-v4prefix`       | `24`        |
+| `COLLECTOR_V6PREFIX`     | `-v6prefix`       | `48`        |
+| `COLLECTOR_SCAN_INTERVAL`| `-scan-interval`  | `10s`       |
+
+**aggregator**:
+
+| Env var                  | Flag          | Default     |
+|--------------------------|---------------|-------------|
+| `AGGREGATOR_LISTEN`      | `-listen`     | `:9091`     |
+| `AGGREGATOR_COLLECTORS`  | `-collectors` | — (required)|
+| `AGGREGATOR_SOURCE`      | `-source`     | hostname    |
+
+**frontend**:
+
+| Env var          | Flag       | Default           |
+|------------------|------------|-------------------|
+| `FRONTEND_LISTEN`| `-listen`  | `:8080`           |
+| `FRONTEND_TARGET`| `-target`  | `localhost:9091`  |
+| `FRONTEND_N`     | `-n`       | `25`              |
+| `FRONTEND_REFRESH`| `-refresh`| `30`              |
+
+---
+
 DESIGN
 
 ## Directory Layout