add skeleton of cgroup stuff

johnstcn · johnstcn · commit 3528c006fdf0 · 2023-06-13T17:33:33.000+01:00
diff --git a/cli/clistat/cgroup.go b/cli/clistat/cgroup.go
@@ -0,0 +1,15 @@
+//go:build !linux
+
+package clistat
+
+// ContainerCPU returns the CPU usage of the container cgroup.
+// On non-Linux platforms, this always returns nil.
+func (s *Statter) ContainerCPU() (*Result, error) {
+	return nil, nil
+}
+
+// ContainerMemory returns the memory usage of the container cgroup.
+// On non-Linux platforms, this always returns nil.
+func (s *Statter) ContainerMemory() (*Result, error) {
+	return nil, nil
+}
diff --git a/cli/clistat/cgroup_linux.go b/cli/clistat/cgroup_linux.go
@@ -0,0 +1,83 @@
+package clistat
+
+import (
+	"time"
+
+	"tailscale.com/types/ptr"
+
+	"golang.org/x/xerrors"
+)
+
+const ()
+
+// CGroupCPU returns the CPU usage of the container cgroup.
+// On non-Linux platforms, this always returns nil.
+func (s *Statter) ContainerCPU() (*Result, error) {
+	// Firstly, check if we are containerized.
+	if ok, err := IsContainerized(); err != nil || !ok {
+		return nil, nil
+	}
+
+	used1, total1, err := cgroupCPU()
+	if err != nil {
+		return nil, xerrors.Errorf("get cgroup CPU usage: %w", err)
+	}
+	<-time.After(s.sampleInterval)
+	used2, total2, err := cgroupCPU()
+	if err != nil {
+		return nil, xerrors.Errorf("get cgroup CPU usage: %w", err)
+	}
+
+	return &Result{
+		Unit:  "cores",
+		Used:  used2 - used1,
+		Total: ptr.To(total2 - total1),
+	}, nil
+}
+
+func cgroupCPU() (used, total float64, err error) {
+	if isCGroupV2() {
+		return cGroupv2CPU()
+	}
+
+	// Fall back to CGroupv1
+	return cGroupv1CPU()
+}
+
+func isCGroupV2() bool {
+	// TODO implement
+	return false
+}
+
+func cGroupv2CPU() (float64, float64, error) {
+	// TODO: implement
+	return 0, 0, nil
+}
+
+func cGroupv1CPU() (float64, float64, error) {
+	// TODO: implement
+	return 0, 0, nil
+}
+
+func (s *Statter) ContainerMemory() (*Result, error) {
+	if ok, err := IsContainerized(); err != nil || !ok {
+		return nil, nil
+	}
+
+	if isCGroupV2() {
+		return cGroupv2Memory()
+	}
+
+	// Fall back to CGroupv1
+	return cGroupv1Memory()
+}
+
+func cGroupv2Memory() (*Result, error) {
+	// TODO implement
+	return nil, nil
+}
+
+func cGroupv1Memory() (*Result, error) {
+	// TODO implement
+	return nil, nil
+}
