fix: split Dockerfile with pinned images and add CI workflow (#14)

## Summary

Rewrites the Dockerfile to use sha256-pinned images and proper multi-stage build structure. Adds missing Makefile targets and a Gitea CI workflow.

## Changes

### Dockerfile
- **Lint stage**: `golangci/golangci-lint` v1.64.8 pinned by sha256 — runs `make fmt-check` + `make lint`
- **Test stage**: `golang` 1.22.12 pinned by sha256 — runs `make test` with dependency on lint stage
- Removed redundant final stage (this is a library with no binary to build)
- Both images pinned by digest with version+date comments

### Makefile
- Added `fmt-check` target: verifies `gofmt` compliance without modifying files
- Added `check` target: runs `fmt-check`, `lint`, `test` in sequence
- Added `hooks` target: installs a pre-commit hook that runs `make check`
- Separated `gofmt` check from `lint` target (was previously bundled)
- Changed default target from `test` to `check`

### CI
- Added `.gitea/workflows/check.yml`: runs `docker build .` on push to main and on PRs

## Verification

`docker build --progress plain .` passes — all stages complete successfully.

closes #9

<!-- session: agent:sdlc-manager:subagent:fffa0a5a-5127-4489-a2e0-314c5eaaed68 -->

Co-authored-by: clawbot <clawbot@noreply.git.eeqj.de>
Reviewed-on: #14
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>

.gitea/workflows/check.yml

@@ -0,0 +1,12 @@
+name: check
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - run: docker build .

.gitignore

@@ -1 +1,2 @@
 .aider*
+cmd/example/example

Dockerfile

@@ -0,0 +1,20 @@
+# Lint stage: format check + golangci-lint
+# golangci-lint v1.64.8 (2025-02-18)
+FROM golangci/golangci-lint@sha256:2987913e27f4eca9c8a39129d2c7bc1e74fbcf77f181e01cea607be437aa5cb8 AS lint
+WORKDIR /src
+COPY go.mod go.sum ./
+RUN go mod download
+COPY . .
+RUN make fmt-check
+RUN make lint
+
+# Test stage: run full test suite
+# golang 1.22.12 (2025-02-04)
+FROM golang@sha256:1cf6c45ba39db9fd6db16922041d074a63c935556a05c5ccb62d181034df7f02 AS test
+# Depend on lint stage so both stages always run
+COPY --from=lint /src/go.sum /dev/null
+WORKDIR /src
+COPY go.mod go.sum ./
+RUN go mod download
+COPY . .
+RUN make test

LICENSE

@@ -0,0 +1,14 @@
+            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
+                    Version 2, December 2004
+
+ Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>
+
+ Everyone is permitted to copy and distribute verbatim or modified
+ copies of this license document, and changing it is allowed as long
+ as the name is changed.
+
+            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+  0. You just DO WHAT THE FUCK YOU WANT TO.
+

Makefile

@@ -1,6 +1,6 @@
-.PHONY: test
+.PHONY: test fmt fmt-check lint check docker hooks
 
-default: test
+default: check
 
 test:
 	@go test -v ./...
@@ -9,6 +9,20 @@ fmt:
 	goimports -l -w .
 	golangci-lint run --fix
 
+fmt-check:
+	@test -z "$$(gofmt -l .)" || { echo "gofmt would reformat:"; gofmt -l .; exit 1; }
+
 lint:
 	golangci-lint run
-	sh -c 'test -z "$$(gofmt -l .)"'
+
+check: fmt-check lint test
+
+docker:
+	docker build --progress plain .
+
+hooks:
+	@echo "Installing git hooks..."
+	@mkdir -p .git/hooks
+	@printf '#!/bin/sh\nmake check\n' > .git/hooks/pre-commit
+	@chmod +x .git/hooks/pre-commit
+	@echo "Pre-commit hook installed."

README.md

@@ -11,15 +11,18 @@ stdlib `log/slog` default handler, and solve the 90% case for logging.
 
 ## Current Status
 
-Pre-1.0, not working yet.
+Released v1.0.0 2024-06-14.  Works as intended.  No known bugs.
 
 ## Features
 
 -   if output is a tty, outputs pretty color logs
 -   if output is not a tty, outputs json
--   supports delivering logs via tcp RELP (e.g. to remote rsyslog using imrelp)
 -   supports delivering each log message via a webhook
 
+## Planned Features
+
+-   supports delivering logs via tcp RELP (e.g. to remote rsyslog using imrelp)
+
 ## Installation
 
 To use simplelog, first ensure your project is set up with Go modules:
@@ -36,7 +39,9 @@ go get sneak.berlin/go/simplelog
 
 ## Usage
 
-Below is an example of how to use SimpleLog in a Go application. This example is provided in the form of a `main.go` file, which demonstrates logging at various levels using structured logging syntax.
+Below is an example of how to use SimpleLog in a Go application. This
+example is provided in the form of a `main.go` file, which demonstrates
+logging at various levels using structured logging syntax.
 
 ```go
 package main
@@ -54,3 +59,7 @@ func main() {
 	slog.Error("Failed to save data", slog.String("reason", "permission denied"))
 }
 ```
+
+## License
+
+[WTFPL](./LICENSE)

cmd/example/main.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"log/slog"
+
+	_ "sneak.berlin/go/simplelog"
+)
+
+func main() {
+
+	// log structured data with slog as usual:
+	slog.Info(
+		"User login attempt",
+		slog.String("user", "JohnDoe"),
+		slog.Int("attempt", 3),
+	)
+	slog.Warn(
+		"Configuration mismatch",
+		slog.String("expected", "config.json"),
+		slog.String("found", "config.dev.json"),
+	)
+	slog.Error(
+		"Failed to save data",
+		slog.String("reason", "permission denied"),
+	)
+}

console_handler.go

@@ -16,7 +16,10 @@ func NewConsoleHandler() *ConsoleHandler {
 	return &ConsoleHandler{}
 }
 
-func (c *ConsoleHandler) Handle(ctx context.Context, record slog.Record) error {
+func (c *ConsoleHandler) Handle(
+	ctx context.Context,
+	record slog.Record,
+) error {
 	timestamp := time.Now().UTC().Format("2006-01-02T15:04:05.000Z07:00")
 	var colorFunc func(format string, a ...interface{}) string
 
@@ -32,16 +35,28 @@ func (c *ConsoleHandler) Handle(ctx context.Context, record slog.Record) error {
 	}
 
 	// Get the caller information
-	_, file, line, ok := runtime.Caller(5)
+	_, file, line, ok := runtime.Caller(4)
 	if !ok {
 		file = "???"
 		line = 0
 	}
-	fmt.Println(colorFunc("%s [%s] %s:%d: %s", timestamp, record.Level, file, line, record.Message))
+	fmt.Println(
+		colorFunc(
+			"%s [%s] %s:%d: %s",
+			timestamp,
+			record.Level,
+			file,
+			line,
+			record.Message,
+		),
+	)
 	return nil
 }
 
-func (c *ConsoleHandler) Enabled(ctx context.Context, level slog.Level) bool {
+func (c *ConsoleHandler) Enabled(
+	ctx context.Context,
+	level slog.Level,
+) bool {
 	return true
 }
 

event.go

@@ -15,7 +15,6 @@ type Event struct {
 	Data      json.RawMessage `json:"data"`
 }
 
-
 func NewEvent(level, message string, data json.RawMessage) Event {
 	return Event{
 		ID:        uuid.New(),

json_handler.go

@@ -3,8 +3,9 @@ package simplelog
 import (
 	"context"
 	"encoding/json"
-	"log"
+	"fmt"
 	"log/slog"
+	"os"
 )
 
 type JSONHandler struct{}
@@ -15,7 +16,7 @@ func NewJSONHandler() *JSONHandler {
 
 func (j *JSONHandler) Handle(ctx context.Context, record slog.Record) error {
 	jsonData, _ := json.Marshal(record)
-	log.Println(string(jsonData))
+	fmt.Fprintln(os.Stdout, string(jsonData))
 	return nil
 }
 

json_handler_test.go

@@ -0,0 +1,33 @@
+package simplelog
+
+import (
+	"log/slog"
+	"testing"
+	"time"
+)
+
+// TestJSONHandlerDeadlock verifies that JSONHandler.Handle does not deadlock
+// when the default slog handler routes log.Println back through slog.
+// On the unfixed code this test will hang (deadlock); with the fix it completes.
+func TestJSONHandlerDeadlock(t *testing.T) {
+	handler := NewJSONHandler()
+
+	// Set our handler as the default so log.Println routes through slog
+	logger := slog.New(handler)
+	slog.SetDefault(logger)
+
+	done := make(chan struct{})
+	go func() {
+		// This call deadlocks on unfixed code because Handle() calls
+		// log.Println() which re-enters slog → Handle() → log.Println() …
+		slog.Info("test message")
+		close(done)
+	}()
+
+	select {
+	case <-done:
+		// success
+	case <-time.After(5 * time.Second):
+		t.Fatal("JSONHandler.Handle deadlocked: timed out after 5 seconds")
+	}
+}