refactor(obs): migrate metrics runtime/schema and tighten migration guards (#2584)

crates/obs/src/metrics/schema/audit.rs

@@ -0,0 +1,52 @@
+// Copyright 2024 RustFS Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#![allow(dead_code)]
+
+use crate::{MetricDescriptor, MetricName, new_counter_md, new_gauge_md, subsystems};
+use std::sync::LazyLock;
+
+const TARGET_ID: &str = "target_id";
+pub const RESULT: &str = "result"; // success / failure
+pub const STATUS: &str = "status"; // success / failure
+
+pub const SUCCESS: &str = "success";
+pub const FAILURE: &str = "failure";
+
+pub static AUDIT_FAILED_MESSAGES_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
+    new_counter_md(
+        MetricName::AuditFailedMessages,
+        "Total number of messages that failed to send since start",
+        &[TARGET_ID],
+        subsystems::AUDIT,
+    )
+});
+
+pub static AUDIT_TARGET_QUEUE_LENGTH_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
+    new_gauge_md(
+        MetricName::AuditTargetQueueLength,
+        "Number of unsent messages in queue for target",
+        &[TARGET_ID],
+        subsystems::AUDIT,
+    )
+});
+
+pub static AUDIT_TOTAL_MESSAGES_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
+    new_counter_md(
+        MetricName::AuditTotalMessages,
+        "Total number of messages sent since start",
+        &[TARGET_ID],
+        subsystems::AUDIT,
+    )
+});