Refactor and move StructuredLoggerFactory from eden to edencommon

Summary:
To support better telemetry and logging in watchman we want to use Eden's components. Lets migrate and detangle the needed pieces.

This change refactors StructuredLoggerFactory to be a template specializing on a stats pointer (e.g. EdenStatsPtr) and then moves it from eden to edencommon.

Reviewed By: kmancini

Differential Revision: D56069823

fbshipit-source-id: 3507d521e809f91746a951c4273c5c323f965fa9

eden/common/telemetry/Stats.h

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include "eden/common/telemetry/StatsGroup.h"
+
+namespace facebook::eden {
+
+struct TelemetryStats : StatsGroup<TelemetryStats> {
+  Counter subprocessLoggerFailure{"telemetry.subprocess_logger_failure"};
+};
+
+} // namespace facebook::eden

eden/common/telemetry/StructuredLoggerFactory.h

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include <folly/logging/xlog.h>
+#include <memory>
+#include <string>
+
+#include "eden/common/telemetry/NullStructuredLogger.h"
+#include "eden/common/telemetry/ScubaStructuredLogger.h"
+#include "eden/common/telemetry/Stats.h"
+#include "eden/common/telemetry/SubprocessScribeLogger.h"
+#include "eden/common/utils/RefPtr.h"
+
+namespace facebook::eden {
+
+class StructuredLogger;
+struct SessionInfo;
+
+/**
+ * Returns a StructuredLogger appropriate for this platform and
+ * configuration.
+ */
+template <typename StatsPtr>
+std::shared_ptr<StructuredLogger> makeDefaultStructuredLogger(
+    const std::string& binary,
+    const std::string& category,
+    SessionInfo sessionInfo,
+    StatsPtr stats) {
+  if (binary.empty()) {
+    return std::make_shared<NullStructuredLogger>();
+  }
+
+  if (category.empty()) {
+    XLOGF(
+        WARN,
+        "Scribe binary '{}' specified, but no category specified. Structured logging is disabled.",
+        binary);
+    return std::make_shared<NullStructuredLogger>();
+  }
+
+  try {
+    auto logger =
+        std::make_unique<SubprocessScribeLogger>(binary.c_str(), category);
+    return std::make_shared<ScubaStructuredLogger>(
+        std::move(logger), std::move(sessionInfo));
+  } catch (const std::exception& ex) {
+    stats->increment(&TelemetryStats::subprocessLoggerFailure, 1);
+    XLOGF(
+        ERR,
+        "Failed to create SubprocessScribeLogger: {}. Structured logging is disabled.",
+        folly::exceptionStr(ex));
+    return std::make_shared<NullStructuredLogger>();
+  }
+}
+
+} // namespace facebook::eden