refactor(logging): add a logging abstraction and move the job logger onto it (#1295)

Add `act/common/logging`: a printf-style `Logger` on a slog-shaped `Handler`, with a logrus-backed handler as the only backend, plus a `logtest` handler for tests. Move the job logger onto it: `common.Logger` returns `*logging.Logger`, the job log formatters and the `Reporter` hook become handlers, and composite step IDs travel in the context.

Logging is tightly coupled to logrus types (hooks, formatters, `Entry.Data`). Going through our own interface first lets the remaining call sites move over with unchanged behavior, and lets the backend be swapped for `log/slog` in one place afterwards. The global process logger and its masking formatter stay on logrus for now.

Assisted-by: Codet
Co-authored-by: bircni <[email protected]>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1295
Reviewed-by: bircni <[email protected]>

internal/app/run/runner_test.go

@@ -18,6 +18,7 @@ import (
 	"time"
 
 	"gitea.com/gitea/runner/act/common"
+	"gitea.com/gitea/runner/act/common/logging"
 	"gitea.com/gitea/runner/act/runner"
 	clientmocks "gitea.com/gitea/runner/internal/pkg/client/mocks"
 	"gitea.com/gitea/runner/internal/pkg/config"
@@ -79,9 +80,9 @@ func TestRunnerRunningCountAndNullLogger(t *testing.T) {
 	r.runningCount.Add(2)
 	require.Equal(t, int64(2), r.RunningCount())
 
-	logger := NullLogger{}.WithJobLogger()
-	require.NotNil(t, logger)
-	require.NotNil(t, logger.Out)
+	handler := NullLogger{}.WithJobLogger()
+	require.NotNil(t, handler)
+	require.False(t, handler.Enabled(t.Context(), logging.LevelError))
 }
 
 func TestRunnerReclaimsVolumesAfterReporting(t *testing.T) {