fix: add http error responses (#494)

This features adds rfc7807 Problem detail responses when an error happens processing a request.

This will greatly improve the common issues  with "blank pages" and "404 pages" issues which should now properly tell the user what input was wrong (group that does not exist, container name that does not exist, etc.)

internal/server/logging.go

@@ -0,0 +1,47 @@
+package server
+
+import (
+	"github.com/gin-gonic/gin"
+	sloggin "github.com/samber/slog-gin"
+	"log/slog"
+)
+
+// StructuredLogger logs a gin HTTP request in JSON format. Allows to set the
+// logger for testing purposes.
+func StructuredLogger(logger *slog.Logger) gin.HandlerFunc {
+	if logger.Enabled(nil, slog.LevelDebug) {
+		return sloggin.NewWithConfig(logger, sloggin.Config{
+			DefaultLevel:     slog.LevelInfo,
+			ClientErrorLevel: slog.LevelWarn,
+			ServerErrorLevel: slog.LevelError,
+
+			WithUserAgent:      false,
+			WithRequestID:      true,
+			WithRequestBody:    false,
+			WithRequestHeader:  false,
+			WithResponseBody:   false,
+			WithResponseHeader: false,
+			WithSpanID:         false,
+			WithTraceID:        false,
+
+			Filters: []sloggin.Filter{},
+		})
+	}
+
+	return sloggin.NewWithConfig(logger, sloggin.Config{
+		DefaultLevel:     slog.LevelInfo,
+		ClientErrorLevel: slog.LevelWarn,
+		ServerErrorLevel: slog.LevelError,
+
+		WithUserAgent:      false,
+		WithRequestID:      true,
+		WithRequestBody:    false,
+		WithRequestHeader:  false,
+		WithResponseBody:   false,
+		WithResponseHeader: false,
+		WithSpanID:         false,
+		WithTraceID:        false,
+
+		Filters: []sloggin.Filter{},
+	})
+}