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

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

@@ -0,0 +1,56 @@
+// 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_gauge_md, subsystems};
+use std::sync::LazyLock;
+
+/// Total memory available on the node
+pub static MEM_TOTAL_MD: LazyLock<MetricDescriptor> =
+    LazyLock::new(|| new_gauge_md(MetricName::MemTotal, "Total memory on the node", &[], subsystems::SYSTEM_MEMORY));
+
+/// Memory currently in use on the node
+pub static MEM_USED_MD: LazyLock<MetricDescriptor> =
+    LazyLock::new(|| new_gauge_md(MetricName::MemUsed, "Used memory on the node", &[], subsystems::SYSTEM_MEMORY));
+
+/// Percentage of total memory currently in use
+pub static MEM_USED_PERC_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
+    new_gauge_md(
+        MetricName::MemUsedPerc,
+        "Used memory percentage on the node",
+        &[],
+        subsystems::SYSTEM_MEMORY,
+    )
+});
+
+/// Memory not currently in use and available for allocation
+pub static MEM_FREE_MD: LazyLock<MetricDescriptor> =
+    LazyLock::new(|| new_gauge_md(MetricName::MemFree, "Free memory on the node", &[], subsystems::SYSTEM_MEMORY));
+
+/// Memory used for file buffers by the kernel
+pub static MEM_BUFFERS_MD: LazyLock<MetricDescriptor> =
+    LazyLock::new(|| new_gauge_md(MetricName::MemBuffers, "Buffers memory on the node", &[], subsystems::SYSTEM_MEMORY));
+
+/// Memory used for caching file data by the kernel
+pub static MEM_CACHE_MD: LazyLock<MetricDescriptor> =
+    LazyLock::new(|| new_gauge_md(MetricName::MemCache, "Cache memory on the node", &[], subsystems::SYSTEM_MEMORY));
+
+/// Memory shared between multiple processes
+pub static MEM_SHARED_MD: LazyLock<MetricDescriptor> =
+    LazyLock::new(|| new_gauge_md(MetricName::MemShared, "Shared memory on the node", &[], subsystems::SYSTEM_MEMORY));
+
+/// Estimate of memory available for new applications without swapping
+pub static MEM_AVAILABLE_MD: LazyLock<MetricDescriptor> =
+    LazyLock::new(|| new_gauge_md(MetricName::MemAvailable, "Available memory on the node", &[], subsystems::SYSTEM_MEMORY));