cgroup: move all metrics initialization to meterics.goqmnguyen0711/adlternative-zh-cgroups-v2

As the metrics detected by Prometheus in cgroups V1 and V2
are basically the same but slightly different, the initialization
of all V1/V2 metrics is put into metrics.go. This makes the
code cleaner and easier to observe the differences between
the detection meterics of V1 and V2.

Signed-off-by: ZheNing Hu <adlternative@gmail.com>

3 files changed, 100 insertions, 83 deletions

diff --git a/internal/cgroups/metrics.go b/internal/cgroups/metrics.go
new file mode 100644
index 000000000..a8ffa618f
--- /dev/null
+++ b/internal/cgroups/metrics.go
@@ -0,0 +1,87 @@
+package cgroups
+
+import "github.com/prometheus/client_golang/prometheus"
+
+type cgroupsMetrics struct {
+	memoryReclaimAttemptsTotal *prometheus.GaugeVec
+	cpuUsage                   *prometheus.GaugeVec
+	cpuCFSPeriods              *prometheus.Desc
+	cpuCFSThrottledPeriods     *prometheus.Desc
+	cpuCFSThrottledTime        *prometheus.Desc
+	procs                      *prometheus.GaugeVec
+}
+
+func newV1CgroupsMetrics() *cgroupsMetrics {
+	return &cgroupsMetrics{
+		memoryReclaimAttemptsTotal: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Name: "gitaly_cgroup_memory_reclaim_attempts_total",
+				Help: "Number of memory usage hits limits",
+			},
+			[]string{"path"},
+		),
+		cpuUsage: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Name: "gitaly_cgroup_cpu_usage_total",
+				Help: "CPU Usage of Cgroup",
+			},
+			[]string{"path", "type"},
+		),
+		cpuCFSPeriods: prometheus.NewDesc(
+			"gitaly_cgroup_cpu_cfs_periods_total",
+			"Number of elapsed enforcement period intervals",
+			[]string{"path"}, nil,
+		),
+		cpuCFSThrottledPeriods: prometheus.NewDesc(
+			"gitaly_cgroup_cpu_cfs_throttled_periods_total",
+			"Number of throttled period intervals",
+			[]string{"path"}, nil,
+		),
+		cpuCFSThrottledTime: prometheus.NewDesc(
+			"gitaly_cgroup_cpu_cfs_throttled_seconds_total",
+			"Total time duration the Cgroup has been throttled",
+			[]string{"path"}, nil,
+		),
+		procs: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Name: "gitaly_cgroup_procs_total",
+				Help: "Total number of procs",
+			},
+			[]string{"path", "subsystem"},
+		),
+	}
+}
+
+func newV2CgroupsMetrics() *cgroupsMetrics {
+	return &cgroupsMetrics{
+		cpuUsage: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Name: "gitaly_cgroup_cpu_usage_total",
+				Help: "CPU Usage of Cgroup",
+			},
+			[]string{"path", "type"},
+		),
+		cpuCFSPeriods: prometheus.NewDesc(
+			"gitaly_cgroup_cpu_cfs_periods_total",
+			"Number of elapsed enforcement period intervals",
+			[]string{"path"}, nil,
+		),
+		cpuCFSThrottledPeriods: prometheus.NewDesc(
+			"gitaly_cgroup_cpu_cfs_throttled_periods_total",
+			"Number of throttled period intervals",
+			[]string{"path"}, nil,
+		),
+		cpuCFSThrottledTime: prometheus.NewDesc(
+			"gitaly_cgroup_cpu_cfs_throttled_seconds_total",
+			"Total time duration the Cgroup has been throttled",
+			[]string{"path"}, nil,
+		),
+		procs: prometheus.NewGaugeVec(
+			prometheus.GaugeOpts{
+				Name: "gitaly_cgroup_procs_total",
+				Help: "Total number of procs",
+			},
+			[]string{"path", "subsystem"},
+		),
+	}
+}
diff --git a/internal/cgroups/v1_linux.go b/internal/cgroups/v1_linux.go
index e9b81103a..22e9ab841 100644
--- a/internal/cgroups/v1_linux.go
+++ b/internal/cgroups/v1_linux.go
@@ -18,15 +18,11 @@ import (
 )
 
 type cgroupV1Handler struct {
-	cfg                        cgroupscfg.Config
-	hierarchy                  func() ([]cgroup1.Subsystem, error)
-	memoryReclaimAttemptsTotal *prometheus.GaugeVec
-	cpuUsage                   *prometheus.GaugeVec
-	cpuCFSPeriods              *prometheus.Desc
-	cpuCFSThrottledPeriods     *prometheus.Desc
-	cpuCFSThrottledTime        *prometheus.Desc
-	procs                      *prometheus.GaugeVec
-	pid                        int
+	cfg       cgroupscfg.Config
+	hierarchy func() ([]cgroup1.Subsystem, error)
+
+	*cgroupsMetrics
+	pid int
 }
 
 func newV1Handler(cfg cgroupscfg.Config, pid int) *cgroupV1Handler {
@@ -36,42 +32,7 @@ func newV1Handler(cfg cgroupscfg.Config, pid int) *cgroupV1Handler {
 		hierarchy: func() ([]cgroup1.Subsystem, error) {
 			return defaultSubsystems(cfg.Mountpoint)
 		},
-		memoryReclaimAttemptsTotal: prometheus.NewGaugeVec(
-			prometheus.GaugeOpts{
-				Name: "gitaly_cgroup_memory_reclaim_attempts_total",
-				Help: "Number of memory usage hits limits",
-			},
-			[]string{"path"},
-		),
-		cpuUsage: prometheus.NewGaugeVec(
-			prometheus.GaugeOpts{
-				Name: "gitaly_cgroup_cpu_usage_total",
-				Help: "CPU Usage of Cgroup",
-			},
-			[]string{"path", "type"},
-		),
-		cpuCFSPeriods: prometheus.NewDesc(
-			"gitaly_cgroup_cpu_cfs_periods_total",
-			"Number of elapsed enforcement period intervals",
-			[]string{"path"}, nil,
-		),
-		cpuCFSThrottledPeriods: prometheus.NewDesc(
-			"gitaly_cgroup_cpu_cfs_throttled_periods_total",
-			"Number of throttled period intervals",
-			[]string{"path"}, nil,
-		),
-		cpuCFSThrottledTime: prometheus.NewDesc(
-			"gitaly_cgroup_cpu_cfs_throttled_seconds_total",
-			"Total time duration the Cgroup has been throttled",
-			[]string{"path"}, nil,
-		),
-		procs: prometheus.NewGaugeVec(
-			prometheus.GaugeOpts{
-				Name: "gitaly_cgroup_procs_total",
-				Help: "Total number of procs",
-			},
-			[]string{"path", "subsystem"},
-		),
+		cgroupsMetrics: newV1CgroupsMetrics(),
 	}
 }
 
diff --git a/internal/cgroups/v2_linux.go b/internal/cgroups/v2_linux.go
index abcbfbdc6..a2f81f60b 100644
--- a/internal/cgroups/v2_linux.go
+++ b/internal/cgroups/v2_linux.go
@@ -20,48 +20,17 @@ import (
 )
 
 type cgroupV2Handler struct {
-	cfg                    cgroupscfg.Config
-	cpuUsage               *prometheus.GaugeVec
-	cpuCFSPeriods          *prometheus.Desc
-	cpuCFSThrottledPeriods *prometheus.Desc
-	cpuCFSThrottledTime    *prometheus.Desc
-	procs                  *prometheus.GaugeVec
-	pid                    int
+	cfg cgroupscfg.Config
+
+	*cgroupsMetrics
+	pid int
 }
 
 func newV2Handler(cfg cgroupscfg.Config, pid int) *cgroupV2Handler {
 	return &cgroupV2Handler{
-		cfg: cfg,
-		pid: pid,
-		cpuUsage: prometheus.NewGaugeVec(
-			prometheus.GaugeOpts{
-				Name: "gitaly_cgroup_cpu_usage_total",
-				Help: "CPU Usage of Cgroup",
-			},
-			[]string{"path", "type"},
-		),
-		cpuCFSPeriods: prometheus.NewDesc(
-			"gitaly_cgroup_cpu_cfs_periods_total",
-			"Number of elapsed enforcement period intervals",
-			[]string{"path"}, nil,
-		),
-		cpuCFSThrottledPeriods: prometheus.NewDesc(
-			"gitaly_cgroup_cpu_cfs_throttled_periods_total",
-			"Number of throttled period intervals",
-			[]string{"path"}, nil,
-		),
-		cpuCFSThrottledTime: prometheus.NewDesc(
-			"gitaly_cgroup_cpu_cfs_throttled_seconds_total",
-			"Total time duration the Cgroup has been throttled",
-			[]string{"path"}, nil,
-		),
-		procs: prometheus.NewGaugeVec(
-			prometheus.GaugeOpts{
-				Name: "gitaly_cgroup_procs_total",
-				Help: "Total number of procs",
-			},
-			[]string{"path", "subsystem"},
-		),
+		cfg:            cfg,
+		pid:            pid,
+		cgroupsMetrics: newV2CgroupsMetrics(),
 	}
 }