Manuel Ganter
5e470c33a5
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Add cgroup-based process grouping to the resource collector. Processes are grouped by their cgroup path, with container names resolved via configurable process-to-container mapping. New features: - Read cgroup info from /proc/[pid]/cgroup (supports v1 and v2) - Parse K8s resource notation (500m, 1Gi, etc.) for CPU/memory limits - Group metrics by container using CGROUP_PROCESS_MAP env var - Calculate usage percentages against limits from CGROUP_LIMITS env var - Output cgroup metrics with CPU cores used, memory RSS, and percentages Environment variables: - CGROUP_PROCESS_MAP: Map process names to container names for discovery - CGROUP_LIMITS: Define CPU/memory limits per container in K8s notation Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
59 lines
1.4 KiB
Go
59 lines
1.4 KiB
Go
// ABOUTME: Reads cgroup information from /proc/[pid]/cgroup.
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// ABOUTME: Supports both cgroup v1 and v2 formats.
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package proc
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import (
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"bufio"
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"fmt"
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"os"
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"strings"
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)
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// CgroupInfo holds cgroup information for a process
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type CgroupInfo struct {
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Path string // The cgroup path (unified for v2, or from memory controller for v1)
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}
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// ReadCgroup reads /proc/[pid]/cgroup and extracts the cgroup path
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func ReadCgroup(procPath string, pid int) (*CgroupInfo, error) {
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path := fmt.Sprintf("%s/%d/cgroup", procPath, pid)
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file, err := os.Open(path)
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if err != nil {
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return nil, fmt.Errorf("opening cgroup file: %w", err)
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}
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defer func() { _ = file.Close() }()
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var cgroupPath string
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scanner := bufio.NewScanner(file)
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for scanner.Scan() {
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line := scanner.Text()
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// Try cgroup v2 first (unified hierarchy)
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// Format: 0::/path
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if path, found := strings.CutPrefix(line, "0::"); found {
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cgroupPath = path
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break
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}
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// Fall back to cgroup v1 - look for memory controller
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// Format: X:memory:/path or X:memory,other:/path
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parts := strings.SplitN(line, ":", 3)
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if len(parts) == 3 {
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controllers := parts[1]
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if strings.Contains(controllers, "memory") {
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cgroupPath = parts[2]
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// Don't break - prefer v2 if found later
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}
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}
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}
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if err := scanner.Err(); err != nil {
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return nil, fmt.Errorf("scanning cgroup file: %w", err)
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}
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return &CgroupInfo{
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Path: cgroupPath,
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}, nil
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}
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