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]>

act/common/logging/logtest/logtest.go

@@ -0,0 +1,72 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+// Package logtest provides a Handler that keeps records in memory for assertions.
+package logtest
+
+import (
+	"context"
+	"slices"
+	"sync"
+
+	"gitea.com/gitea/runner/act/common/logging"
+)
+
+type store struct {
+	mu      sync.Mutex
+	records []logging.Record
+}
+
+// Handler records what it receives at or above its level. Loggers derived with WithAttrs share one store.
+type Handler struct {
+	store    *store
+	attrs    []logging.Attr
+	minLevel logging.Level
+}
+
+// New records from LevelInfo up, like the logger of logrus's hooks/test.
+func New() *Handler {
+	return NewWithLevel(logging.LevelInfo)
+}
+
+func NewWithLevel(minLevel logging.Level) *Handler {
+	return &Handler{store: &store{}, minLevel: minLevel}
+}
+
+func (h *Handler) Enabled(_ context.Context, level logging.Level) bool { return level >= h.minLevel }
+
+// Handle stores the record with the attributes accumulated by WithAttrs placed first.
+func (h *Handler) Handle(_ context.Context, r logging.Record) error {
+	r.Attrs = append(slices.Clone(h.attrs), r.Attrs...)
+	h.store.mu.Lock()
+	defer h.store.mu.Unlock()
+	h.store.records = append(h.store.records, r)
+	return nil
+}
+
+func (h *Handler) WithAttrs(attrs []logging.Attr) logging.Handler {
+	return &Handler{store: h.store, attrs: append(slices.Clone(h.attrs), attrs...), minLevel: h.minLevel}
+}
+
+func (h *Handler) AllRecords() []logging.Record {
+	h.store.mu.Lock()
+	defer h.store.mu.Unlock()
+	return slices.Clone(h.store.records)
+}
+
+// LastRecord returns nil when nothing was logged.
+func (h *Handler) LastRecord() *logging.Record {
+	h.store.mu.Lock()
+	defer h.store.mu.Unlock()
+	if len(h.store.records) == 0 {
+		return nil
+	}
+	r := h.store.records[len(h.store.records)-1]
+	return &r
+}
+
+func (h *Handler) Reset() {
+	h.store.mu.Lock()
+	defer h.store.mu.Unlock()
+	h.store.records = nil
+}