ipng/nginx-logtail
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Add Docker setup, add environment vars for each flag

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This commit is contained in:
Pim van Pelt
2026-03-25 06:41:13 +01:00
parent 129246d85b
commit d2dcd88c4b
6 changed files with 174 additions and 16 deletions
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14
Dockerfile Normal file
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@@ -0,0 +1,14 @@
FROM golang:1.24-alpine AS builder
WORKDIR /src
COPY go.mod go.sum ./
RUN go mod download
COPY . .
RUN CGO_ENABLED=0 go build -trimpath -ldflags="-s -w" -o /out/collector ./cmd/collector && \
CGO_ENABLED=0 go build -trimpath -ldflags="-s -w" -o /out/aggregator ./cmd/aggregator && \
CGO_ENABLED=0 go build -trimpath -ldflags="-s -w" -o /out/frontend ./cmd/frontend && \
CGO_ENABLED=0 go build -trimpath -ldflags="-s -w" -o /out/cli ./cmd/cli
FROM scratch
COPY --from=builder /out/ /usr/local/bin/

65
README.md
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@@ -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

15
cmd/aggregator/main.go
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@@ -15,13 +15,13 @@ import (
)
func main() {
listen := flag.String("listen", ":9091", "gRPC listen address")
collectors := flag.String("collectors", "", "comma-separated collector host:port addresses")
source := flag.String("source", hostname(), "name for this aggregator in responses")
listen := flag.String("listen", envOr("AGGREGATOR_LISTEN", ":9091"), "gRPC listen address (env: AGGREGATOR_LISTEN)")
collectors := flag.String("collectors", envOr("AGGREGATOR_COLLECTORS", ""), "comma-separated collector host:port addresses (env: AGGREGATOR_COLLECTORS)")
source := flag.String("source", envOr("AGGREGATOR_SOURCE", hostname()), "name for this aggregator in responses (env: AGGREGATOR_SOURCE, default: hostname)")
flag.Parse()
if *collectors == "" {
log.Fatal("aggregator: --collectors is required")
log.Fatal("aggregator: --collectors / AGGREGATOR_COLLECTORS is required")
}
ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
@@ -72,3 +72,10 @@ func hostname() string {
}
return h
}
func envOr(key, def string) string {
if v := os.Getenv(key); v != "" {
return v
}
return def
}

44
cmd/collector/main.go
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@@ -10,6 +10,7 @@ import (
"os"
"os/signal"
"path/filepath"
"strconv"
"strings"
"syscall"
"time"
@@ -19,14 +20,14 @@ import (
)
func main() {
listen := flag.String("listen", ":9090", "gRPC listen address")
promListen := flag.String("prom-listen", ":9100", "Prometheus metrics listen address (empty to disable)")
logPaths := flag.String("logs", "", "comma-separated log file paths/globs to tail")
logsFile := flag.String("logs-file", "", "file containing one log path/glob per line")
source := flag.String("source", hostname(), "name for this collector (default: hostname)")
v4prefix := flag.Int("v4prefix", 24, "IPv4 prefix length for client bucketing")
v6prefix := flag.Int("v6prefix", 48, "IPv6 prefix length for client bucketing")
scanInterval := flag.Duration("scan-interval", 10*time.Second, "how often to rescan glob patterns for new/removed files")
listen := flag.String("listen", envOr("COLLECTOR_LISTEN", ":9090"), "gRPC listen address (env: COLLECTOR_LISTEN)")
promListen := flag.String("prom-listen", envOr("COLLECTOR_PROM_LISTEN", ":9100"), "Prometheus metrics listen address, empty to disable (env: COLLECTOR_PROM_LISTEN)")
logPaths := flag.String("logs", envOr("COLLECTOR_LOGS", ""), "comma-separated log file paths/globs to tail (env: COLLECTOR_LOGS)")
logsFile := flag.String("logs-file", envOr("COLLECTOR_LOGS_FILE", ""), "file containing one log path/glob per line (env: COLLECTOR_LOGS_FILE)")
source := flag.String("source", envOr("COLLECTOR_SOURCE", hostname()), "name for this collector (env: COLLECTOR_SOURCE, default: hostname)")
v4prefix := flag.Int("v4prefix", envOrInt("COLLECTOR_V4PREFIX", 24), "IPv4 prefix length for client bucketing (env: COLLECTOR_V4PREFIX)")
v6prefix := flag.Int("v6prefix", envOrInt("COLLECTOR_V6PREFIX", 48), "IPv6 prefix length for client bucketing (env: COLLECTOR_V6PREFIX)")
scanInterval := flag.Duration("scan-interval", envOrDuration("COLLECTOR_SCAN_INTERVAL", 10*time.Second), "how often to rescan glob patterns for new/removed files (env: COLLECTOR_SCAN_INTERVAL)")
flag.Parse()
patterns := collectPatterns(*logPaths, *logsFile)
@@ -154,3 +155,30 @@ func hostname() string {
}
return h
}
func envOr(key, def string) string {
if v := os.Getenv(key); v != "" {
return v
}
return def
}
func envOrInt(key string, def int) int {
if v := os.Getenv(key); v != "" {
if n, err := strconv.Atoi(v); err == nil {
return n
}
log.Printf("collector: invalid int for %s=%q, using default %d", key, v, def)
}
return def
}
func envOrDuration(key string, def time.Duration) time.Duration {
if v := os.Getenv(key); v != "" {
if d, err := time.ParseDuration(v); err == nil {
return d
}
log.Printf("collector: invalid duration for %s=%q, using default %s", key, v, def)
}
return def
}

26
cmd/frontend/main.go
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@@ -9,6 +9,7 @@ import (
"net/http"
"os"
"os/signal"
"strconv"
"syscall"
)
@@ -16,10 +17,10 @@ import (
var templatesFS embed.FS
func main() {
listen := flag.String("listen", ":8080", "HTTP listen address")
target := flag.String("target", "localhost:9091", "default gRPC endpoint (aggregator or collector)")
n := flag.Int("n", 25, "default number of table rows")
refresh := flag.Int("refresh", 30, "meta-refresh interval in seconds (0 = disabled)")
listen := flag.String("listen", envOr("FRONTEND_LISTEN", ":8080"), "HTTP listen address (env: FRONTEND_LISTEN)")
target := flag.String("target", envOr("FRONTEND_TARGET", "localhost:9091"), "default gRPC endpoint, aggregator or collector (env: FRONTEND_TARGET)")
n := flag.Int("n", envOrInt("FRONTEND_N", 25), "default number of table rows (env: FRONTEND_N)")
refresh := flag.Int("refresh", envOrInt("FRONTEND_REFRESH", 30), "meta-refresh interval in seconds, 0 to disable (env: FRONTEND_REFRESH)")
flag.Parse()
funcMap := template.FuncMap{"fmtCount": fmtCount}
@@ -51,3 +52,20 @@ func main() {
log.Printf("frontend: shutting down")
srv.Shutdown(context.Background())
}
func envOr(key, def string) string {
if v := os.Getenv(key); v != "" {
return v
}
return def
}
func envOrInt(key string, def int) int {
if v := os.Getenv(key); v != "" {
if n, err := strconv.Atoi(v); err == nil {
return n
}
log.Printf("frontend: invalid int for %s=%q, using default %d", key, v, def)
}
return def
}

26
docker-compose.yml Normal file
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@@ -0,0 +1,26 @@
services:
aggregator:
build: .
image: git.ipng.ch/ipng/nginx-logtail
command: ["/usr/local/bin/aggregator"]
restart: unless-stopped
environment:
AGGREGATOR_LISTEN: ":9091"
AGGREGATOR_COLLECTORS: "" # e.g. "collector1:9090,collector2:9090"
AGGREGATOR_SOURCE: "" # defaults to container hostname
ports:
- "9091:9091"
frontend:
image: git.ipng.ch/ipng/nginx-logtail
command: ["/usr/local/bin/frontend"]
restart: unless-stopped
environment:
FRONTEND_LISTEN: ":8080"
FRONTEND_TARGET: "aggregator:9091"
FRONTEND_N: "25"
FRONTEND_REFRESH: "30"
ports:
- "8080:8080"
depends_on:
- aggregator