|
| 1 | +package clistat |
| 2 | + |
| 3 | +import ( |
| 4 | + "bufio" |
| 5 | + "bytes" |
| 6 | + "strconv" |
| 7 | + "strings" |
| 8 | + |
| 9 | + "github.com/spf13/afero" |
| 10 | + "golang.org/x/xerrors" |
| 11 | + "tailscale.com/types/ptr" |
| 12 | +) |
| 13 | + |
| 14 | +// Paths for CGroupV1. |
| 15 | +// Ref: https://www.kernel.org/doc/Documentation/cgroup-v1/cpuacct.txt |
| 16 | +const ( |
| 17 | + // CPU usage of all tasks in cgroup in nanoseconds. |
| 18 | + cgroupV1CPUAcctUsage = "/sys/fs/cgroup/cpu/cpuacct.usage" |
| 19 | + // Alternate path |
| 20 | + cgroupV1CPUAcctUsageAlt = "/sys/fs/cgroup/cpu,cpuacct/cpuacct.usage" |
| 21 | + // CFS quota and period for cgroup in MICROseconds |
| 22 | + cgroupV1CFSQuotaUs = "/sys/fs/cgroup/cpu,cpuacct/cpu.cfs_quota_us" |
| 23 | + cgroupV1CFSPeriodUs = "/sys/fs/cgroup/cpu,cpuacct/cpu.cfs_period_us" |
| 24 | + // Maximum memory usable by cgroup in bytes |
| 25 | + cgroupV1MemoryMaxUsageBytes = "/sys/fs/cgroup/memory/memory.max_usage_in_bytes" |
| 26 | + // Current memory usage of cgroup in bytes |
| 27 | + cgroupV1MemoryUsageBytes = "/sys/fs/cgroup/memory/memory.usage_in_bytes" |
| 28 | + // Other memory stats - we are interested in total_inactive_file |
| 29 | + cgroupV1MemoryStat = "/sys/fs/cgroup/memory/memory.stat" |
| 30 | +) |
| 31 | + |
| 32 | +// Paths for CGroupV2. |
| 33 | +// Ref: https://docs.kernel.org/admin-guide/cgroup-v2.html |
| 34 | +const ( |
| 35 | + // Contains quota and period in microseconds separated by a space. |
| 36 | + cgroupV2CPUMax = "/sys/fs/cgroup/cpu.max" |
| 37 | + // Contains current CPU usage under usage_usec |
| 38 | + cgroupV2CPUStat = "/sys/fs/cgroup/cpu.stat" |
| 39 | + // Contains current cgroup memory usage in bytes. |
| 40 | + cgroupV2MemoryUsageBytes = "/sys/fs/cgroup/memory.current" |
| 41 | + // Contains max cgroup memory usage in bytes. |
| 42 | + cgroupV2MemoryMaxBytes = "/sys/fs/cgroup/memory.max" |
| 43 | + // Other memory stats - we are interested in total_inactive_file |
| 44 | + cgroupV2MemoryStat = "/sys/fs/cgroup/memory.stat" |
| 45 | +) |
| 46 | + |
| 47 | +// ContainerCPU returns the CPU usage of the container cgroup. |
| 48 | +// This is calculated as difference of two samples of the |
| 49 | +// CPU usage of the container cgroup. |
| 50 | +// The total is read from the relevant path in /sys/fs/cgroup. |
| 51 | +// If there is no limit set, the total is assumed to be the |
| 52 | +// number of host cores multiplied by the CFS period. |
| 53 | +// If the system is not containerized, this always returns nil. |
| 54 | +func (s *Statter) ContainerCPU() (*Result, error) { |
| 55 | + // Firstly, check if we are containerized. |
| 56 | + if ok, err := IsContainerized(s.fs); err != nil || !ok { |
| 57 | + return nil, nil //nolint: nilnil |
| 58 | + } |
| 59 | + |
| 60 | + total, err := s.cGroupCPUTotal() |
| 61 | + if err != nil { |
| 62 | + return nil, xerrors.Errorf("get total cpu: %w", err) |
| 63 | + } |
| 64 | + |
| 65 | + used1, err := s.cGroupCPUUsed() |
| 66 | + if err != nil { |
| 67 | + return nil, xerrors.Errorf("get cgroup CPU usage: %w", err) |
| 68 | + } |
| 69 | + |
| 70 | + // The measurements in /sys/fs/cgroup are counters. |
| 71 | + // We need to wait for a bit to get a difference. |
| 72 | + // Note that someone could reset the counter in the meantime. |
| 73 | + // We can't do anything about that. |
| 74 | + s.wait(s.sampleInterval) |
| 75 | + |
| 76 | + used2, err := s.cGroupCPUUsed() |
| 77 | + if err != nil { |
| 78 | + return nil, xerrors.Errorf("get cgroup CPU usage: %w", err) |
| 79 | + } |
| 80 | + |
| 81 | + if used2 < used1 { |
| 82 | + // Someone reset the counter. Best we can do is count from zero. |
| 83 | + used1 = 0 |
| 84 | + } |
| 85 | + |
| 86 | + r := &Result{ |
| 87 | + Unit: "cores", |
| 88 | + Used: used2 - used1, |
| 89 | + Total: ptr.To(total), |
| 90 | + } |
| 91 | + return r, nil |
| 92 | +} |
| 93 | + |
| 94 | +func (s *Statter) cGroupCPUTotal() (used float64, err error) { |
| 95 | + if s.isCGroupV2() { |
| 96 | + return s.cGroupV2CPUTotal() |
| 97 | + } |
| 98 | + |
| 99 | + // Fall back to CGroupv1 |
| 100 | + return s.cGroupV1CPUTotal() |
| 101 | +} |
| 102 | + |
| 103 | +func (s *Statter) cGroupCPUUsed() (used float64, err error) { |
| 104 | + if s.isCGroupV2() { |
| 105 | + return s.cGroupV2CPUUsed() |
| 106 | + } |
| 107 | + |
| 108 | + return s.cGroupV1CPUUsed() |
| 109 | +} |
| 110 | + |
| 111 | +func (s *Statter) isCGroupV2() bool { |
| 112 | + // Check for the presence of /sys/fs/cgroup/cpu.max |
| 113 | + _, err := s.fs.Stat(cgroupV2CPUMax) |
| 114 | + return err == nil |
| 115 | +} |
| 116 | + |
| 117 | +func (s *Statter) cGroupV2CPUUsed() (used float64, err error) { |
| 118 | + usageUs, err := readInt64Prefix(s.fs, cgroupV2CPUStat, "usage_usec") |
| 119 | + if err != nil { |
| 120 | + return 0, xerrors.Errorf("get cgroupv2 cpu used: %w", err) |
| 121 | + } |
| 122 | + periodUs, err := readInt64SepIdx(s.fs, cgroupV2CPUMax, " ", 1) |
| 123 | + if err != nil { |
| 124 | + return 0, xerrors.Errorf("get cpu period: %w", err) |
| 125 | + } |
| 126 | + |
| 127 | + return float64(usageUs) / float64(periodUs), nil |
| 128 | +} |
| 129 | + |
| 130 | +func (s *Statter) cGroupV2CPUTotal() (total float64, err error) { |
| 131 | + var quotaUs, periodUs int64 |
| 132 | + periodUs, err = readInt64SepIdx(s.fs, cgroupV2CPUMax, " ", 1) |
| 133 | + if err != nil { |
| 134 | + return 0, xerrors.Errorf("get cpu period: %w", err) |
| 135 | + } |
| 136 | + |
| 137 | + quotaUs, err = readInt64SepIdx(s.fs, cgroupV2CPUMax, " ", 0) |
| 138 | + if err != nil { |
| 139 | + // Fall back to number of cores |
| 140 | + quotaUs = int64(s.nproc) * periodUs |
| 141 | + } |
| 142 | + |
| 143 | + return float64(quotaUs) / float64(periodUs), nil |
| 144 | +} |
| 145 | + |
| 146 | +func (s *Statter) cGroupV1CPUTotal() (float64, error) { |
| 147 | + periodUs, err := readInt64(s.fs, cgroupV1CFSPeriodUs) |
| 148 | + if err != nil { |
| 149 | + return 0, xerrors.Errorf("read cpu period: %w", err) |
| 150 | + } |
| 151 | + |
| 152 | + quotaUs, err := readInt64(s.fs, cgroupV1CFSQuotaUs) |
| 153 | + if err != nil { |
| 154 | + return 0, xerrors.Errorf("read cpu quota: %w", err) |
| 155 | + } |
| 156 | + |
| 157 | + if quotaUs < 0 { |
| 158 | + // Fall back to the number of cores |
| 159 | + quotaUs = int64(s.nproc) * periodUs |
| 160 | + } |
| 161 | + |
| 162 | + return float64(quotaUs) / float64(periodUs), nil |
| 163 | +} |
| 164 | + |
| 165 | +func (s *Statter) cGroupV1CPUUsed() (float64, error) { |
| 166 | + usageNs, err := readInt64(s.fs, cgroupV1CPUAcctUsage) |
| 167 | + if err != nil { |
| 168 | + // try alternate path |
| 169 | + usageNs, err = readInt64(s.fs, cgroupV1CPUAcctUsageAlt) |
| 170 | + if err != nil { |
| 171 | + return 0, xerrors.Errorf("read cpu used: %w", err) |
| 172 | + } |
| 173 | + } |
| 174 | + |
| 175 | + // usage is in ns, convert to us |
| 176 | + usageNs /= 1000 |
| 177 | + periodUs, err := readInt64(s.fs, cgroupV1CFSPeriodUs) |
| 178 | + if err != nil { |
| 179 | + return 0, xerrors.Errorf("get cpu period: %w", err) |
| 180 | + } |
| 181 | + |
| 182 | + return float64(usageNs) / float64(periodUs), nil |
| 183 | +} |
| 184 | + |
| 185 | +// ContainerMemory returns the memory usage of the container cgroup. |
| 186 | +// If the system is not containerized, this always returns nil. |
| 187 | +func (s *Statter) ContainerMemory() (*Result, error) { |
| 188 | + if ok, err := IsContainerized(s.fs); err != nil || !ok { |
| 189 | + return nil, nil //nolint:nilnil |
| 190 | + } |
| 191 | + |
| 192 | + if s.isCGroupV2() { |
| 193 | + return s.cGroupV2Memory() |
| 194 | + } |
| 195 | + |
| 196 | + // Fall back to CGroupv1 |
| 197 | + return s.cGroupV1Memory() |
| 198 | +} |
| 199 | + |
| 200 | +func (s *Statter) cGroupV2Memory() (*Result, error) { |
| 201 | + maxUsageBytes, err := readInt64(s.fs, cgroupV2MemoryMaxBytes) |
| 202 | + if err != nil { |
| 203 | + return nil, xerrors.Errorf("read memory total: %w", err) |
| 204 | + } |
| 205 | + |
| 206 | + currUsageBytes, err := readInt64(s.fs, cgroupV2MemoryUsageBytes) |
| 207 | + if err != nil { |
| 208 | + return nil, xerrors.Errorf("read memory usage: %w", err) |
| 209 | + } |
| 210 | + |
| 211 | + inactiveFileBytes, err := readInt64Prefix(s.fs, cgroupV2MemoryStat, "inactive_file") |
| 212 | + if err != nil { |
| 213 | + return nil, xerrors.Errorf("read memory stats: %w", err) |
| 214 | + } |
| 215 | + |
| 216 | + return &Result{ |
| 217 | + Total: ptr.To(float64(maxUsageBytes)), |
| 218 | + Used: float64(currUsageBytes - inactiveFileBytes), |
| 219 | + Unit: "B", |
| 220 | + }, nil |
| 221 | +} |
| 222 | + |
| 223 | +func (s *Statter) cGroupV1Memory() (*Result, error) { |
| 224 | + maxUsageBytes, err := readInt64(s.fs, cgroupV1MemoryMaxUsageBytes) |
| 225 | + if err != nil { |
| 226 | + return nil, xerrors.Errorf("read memory total: %w", err) |
| 227 | + } |
| 228 | + |
| 229 | + // need a space after total_rss so we don't hit something else |
| 230 | + usageBytes, err := readInt64(s.fs, cgroupV1MemoryUsageBytes) |
| 231 | + if err != nil { |
| 232 | + return nil, xerrors.Errorf("read memory usage: %w", err) |
| 233 | + } |
| 234 | + |
| 235 | + totalInactiveFileBytes, err := readInt64Prefix(s.fs, cgroupV1MemoryStat, "total_inactive_file") |
| 236 | + if err != nil { |
| 237 | + return nil, xerrors.Errorf("read memory stats: %w", err) |
| 238 | + } |
| 239 | + |
| 240 | + // Total memory used is usage - total_inactive_file |
| 241 | + return &Result{ |
| 242 | + Total: ptr.To(float64(maxUsageBytes)), |
| 243 | + Used: float64(usageBytes - totalInactiveFileBytes), |
| 244 | + Unit: "B", |
| 245 | + }, nil |
| 246 | +} |
| 247 | + |
| 248 | +// read an int64 value from path |
| 249 | +func readInt64(fs afero.Fs, path string) (int64, error) { |
| 250 | + data, err := afero.ReadFile(fs, path) |
| 251 | + if err != nil { |
| 252 | + return 0, xerrors.Errorf("read %s: %w", path, err) |
| 253 | + } |
| 254 | + |
| 255 | + val, err := strconv.ParseInt(string(bytes.TrimSpace(data)), 10, 64) |
| 256 | + if err != nil { |
| 257 | + return 0, xerrors.Errorf("parse %s: %w", path, err) |
| 258 | + } |
| 259 | + |
| 260 | + return val, nil |
| 261 | +} |
| 262 | + |
| 263 | +// read an int64 value from path at field idx separated by sep |
| 264 | +func readInt64SepIdx(fs afero.Fs, path, sep string, idx int) (int64, error) { |
| 265 | + data, err := afero.ReadFile(fs, path) |
| 266 | + if err != nil { |
| 267 | + return 0, xerrors.Errorf("read %s: %w", path, err) |
| 268 | + } |
| 269 | + |
| 270 | + parts := strings.Split(string(data), sep) |
| 271 | + if len(parts) < idx { |
| 272 | + return 0, xerrors.Errorf("expected line %q to have at least %d parts", string(data), idx+1) |
| 273 | + } |
| 274 | + |
| 275 | + val, err := strconv.ParseInt(strings.TrimSpace(parts[idx]), 10, 64) |
| 276 | + if err != nil { |
| 277 | + return 0, xerrors.Errorf("parse %s: %w", path, err) |
| 278 | + } |
| 279 | + |
| 280 | + return val, nil |
| 281 | +} |
| 282 | + |
| 283 | +// read the first int64 value from path prefixed with prefix |
| 284 | +func readInt64Prefix(fs afero.Fs, path, prefix string) (int64, error) { |
| 285 | + data, err := afero.ReadFile(fs, path) |
| 286 | + if err != nil { |
| 287 | + return 0, xerrors.Errorf("read %s: %w", path, err) |
| 288 | + } |
| 289 | + |
| 290 | + scn := bufio.NewScanner(bytes.NewReader(data)) |
| 291 | + for scn.Scan() { |
| 292 | + line := scn.Text() |
| 293 | + if !strings.HasPrefix(line, prefix) { |
| 294 | + continue |
| 295 | + } |
| 296 | + |
| 297 | + parts := strings.Fields(line) |
| 298 | + if len(parts) != 2 { |
| 299 | + return 0, xerrors.Errorf("parse %s: expected two fields but got %s", path, line) |
| 300 | + } |
| 301 | + |
| 302 | + val, err := strconv.ParseInt(strings.TrimSpace(parts[1]), 10, 64) |
| 303 | + if err != nil { |
| 304 | + return 0, xerrors.Errorf("parse %s: %w", path, err) |
| 305 | + } |
| 306 | + |
| 307 | + return val, nil |
| 308 | + } |
| 309 | + |
| 310 | + return 0, xerrors.Errorf("parse %s: did not find line with prefix %s", path, prefix) |
| 311 | +} |
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