Merge pull request 'fix: JSONHandler deadlock from recursive log.Println (closes #3)' (#4) from clawbot/simplelog:fix/json-handler-deadlock into main

Reviewed-on: #4

Dockerfile

@@ -0,0 +1,39 @@
+# First stage: Use the golangci-lint image to run the linter
+FROM golangci/golangci-lint:latest as lint
+
+# Set the Current Working Directory inside the container
+WORKDIR /app
+
+# Copy the go.mod file and the rest of the application code
+COPY go.mod ./
+COPY . .
+
+# Run golangci-lint
+RUN golangci-lint run
+
+RUN sh -c 'test -z "$(gofmt -l .)"'
+
+# Second stage: Use the official Golang image to run tests
+FROM golang:1.22 as test
+
+# Set the Current Working Directory inside the container
+WORKDIR /app
+
+# Copy the go.mod file and the rest of the application code
+COPY go.mod ./
+COPY . .
+
+# Run tests
+RUN go test -v ./...
+
+# Final stage: Combine the linting and testing stages
+FROM golang:1.22 as final
+
+# Ensure that the linting stage succeeded
+WORKDIR /app
+COPY --from=lint /app .
+COPY --from=test /app .
+
+# Set the final CMD to something minimal since we only needed to verify lint and tests during build
+CMD ["echo", "Build and tests passed successfully!"]
+

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

@@ -12,3 +12,6 @@ fmt:
 lint:
 	golangci-lint run
 	sh -c 'test -z "$$(gofmt -l .)"'
+
+docker:
+	docker build --progress plain .

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)

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")
+	}
+}