diff --git a/proc_cgroups.go b/proc_cgroups.go new file mode 100644 index 000000000..24d4dce9c --- /dev/null +++ b/proc_cgroups.go @@ -0,0 +1,98 @@ +// Copyright 2021 The Prometheus Authors +// 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. + +package procfs + +import ( + "bufio" + "bytes" + "fmt" + "strconv" + "strings" + + "github.com/prometheus/procfs/internal/util" +) + +// CgroupSummary models one line from /proc/cgroups. +// This file contains information about the controllers that are compiled into the kernel. +// +// Also see http://man7.org/linux/man-pages/man7/cgroups.7.html +type CgroupSummary struct { + // The name of the controller. controller is also known as subsystem. + SubsysName string + // The unique ID of the cgroup hierarchy on which this controller is mounted. + Hierarchy int + // The number of control groups in this hierarchy using this controller. + Cgroups int + // This field contains the value 1 if this controller is enabled, or 0 if it has been disabled + Enabled int +} + +// parseCgroupSummary parses each line of the /proc/cgroup file +// Line format is `subsys_name hierarchy num_cgroups enabled`. +func parseCgroupSummaryString(CgroupSummaryStr string) (*CgroupSummary, error) { + var err error + + fields := strings.Fields(CgroupSummaryStr) + // require at least 4 fields + if len(fields) < 4 { + return nil, fmt.Errorf("at least 4 fields required, found %d fields in cgroup info string: %s", len(fields), CgroupSummaryStr) + } + + CgroupSummary := &CgroupSummary{ + SubsysName: fields[0], + } + CgroupSummary.Hierarchy, err = strconv.Atoi(fields[1]) + if err != nil { + return nil, fmt.Errorf("failed to parse hierarchy ID") + } + CgroupSummary.Cgroups, err = strconv.Atoi(fields[2]) + if err != nil { + return nil, fmt.Errorf("failed to parse Cgroup Num") + } + CgroupSummary.Enabled, err = strconv.Atoi(fields[3]) + if err != nil { + return nil, fmt.Errorf("failed to parse Enabled") + } + return CgroupSummary, nil +} + +// parseCgroupSummary reads each line of the /proc/cgroup file. +func parseCgroupSummary(data []byte) ([]CgroupSummary, error) { + var CgroupSummarys []CgroupSummary + scanner := bufio.NewScanner(bytes.NewReader(data)) + for scanner.Scan() { + CgroupSummaryString := scanner.Text() + // ignore comment lines + if strings.HasPrefix(CgroupSummaryString, "#") { + continue + } + CgroupSummary, err := parseCgroupSummaryString(CgroupSummaryString) + if err != nil { + return nil, err + } + CgroupSummarys = append(CgroupSummarys, *CgroupSummary) + } + + err := scanner.Err() + return CgroupSummarys, err +} + +// CgroupSummarys returns information about current /proc/cgroups. +func (fs FS) CgroupSummarys() ([]CgroupSummary, error) { + data, err := util.ReadFileNoStat(fs.proc.Path("cgroups")) + if err != nil { + return nil, err + } + return parseCgroupSummary(data) +} diff --git a/proc_cgroups_test.go b/proc_cgroups_test.go new file mode 100644 index 000000000..b0a61d24b --- /dev/null +++ b/proc_cgroups_test.go @@ -0,0 +1,64 @@ +// Copyright 2021 The Prometheus Authors +// 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. + +package procfs + +import ( + "reflect" + "testing" +) + +func TestParseCgroupSummaryString(t *testing.T) { + tests := []struct { + name string + s string + shouldErr bool + CgroupSummary *CgroupSummary + }{ + { + name: "cpuset simple line", + s: "cpuset 7 148 1", + shouldErr: false, + CgroupSummary: &CgroupSummary{ + SubsysName: "cpuset", + Hierarchy: 7, + Cgroups: 148, + Enabled: 1, + }, + }, + { + name: "memory cgroup number mis format", + s: "memory 9 ## 1", + shouldErr: true, + CgroupSummary: nil, + }, + } + + for i, test := range tests { + t.Logf("[%02d] test %q", i, test.name) + + CgroupSummary, err := parseCgroupSummaryString(test.s) + + if test.shouldErr && err == nil { + t.Errorf("%s: expected an error, but none occurred", test.name) + } + if !test.shouldErr && err != nil { + t.Errorf("%s: unexpected error: %v", test.name, err) + } + + if want, have := test.CgroupSummary, CgroupSummary; !reflect.DeepEqual(want, have) { + t.Errorf("cgroup:\nwant:\n%+v\nhave:\n%+v", want, have) + } + } + +}