dotcloud/docker

//go:build !windows

package daemon // import "github.com/docker/docker/daemon"

import (
    "context"
    "net"
    "net/http"
    "path/filepath"
    "strings"
    "time"

    "github.com/containerd/log"
    "github.com/docker/docker/daemon/config"
    "github.com/docker/docker/pkg/plugingetter"
    "github.com/docker/docker/pkg/plugins"
    "github.com/docker/docker/plugin"
    metrics "github.com/docker/go-metrics"
    specs "github.com/opencontainers/runtime-spec/specs-go"
    "github.com/pkg/errors"
    "golang.org/x/sys/unix"
)

func (daemon *Daemon) listenMetricsSock(cfg *config.Config) (string, error) {
    path := filepath.Join(cfg.ExecRoot, "metrics.sock")
    unix.Unlink(path)
    l, err := net.Listen("unix", path)
    if err != nil {
        return "", errors.Wrap(err, "error setting up metrics plugin listener")
    }

    mux := http.NewServeMux()
    mux.Handle("/metrics", metrics.Handler())
    go func() {
        log.G(context.TODO()).Debugf("metrics API listening on %s", l.Addr())
        srv := &http.Server{
            Handler:           mux,
            ReadHeaderTimeout: 5 * time.Minute, // "G112: Potential Slowloris Attack (gosec)"; not a real concern for our use, so setting a long timeout.
        }
        if err := srv.Serve(l); err != nil && !strings.Contains(err.Error(), "use of closed network connection") {
            log.G(context.TODO()).WithError(err).Error("error serving metrics API")
        }
    }()
    daemon.metricsPluginListener = l
    return path, nil
}

func registerMetricsPluginCallback(store *plugin.Store, sockPath string) {
    store.RegisterRuntimeOpt(metricsPluginType, func(s *specs.Spec) {
        f := plugin.WithSpecMounts([]specs.Mount{
            {Type: "bind", Source: sockPath, Destination: "/run/docker/metrics.sock", Options: []string{"bind", "ro"}},
        })
        f(s)
    })
    store.Handle(metricsPluginType, func(name string, client *plugins.Client) {
        // Use lookup since nothing in the system can really reference it, no need
        // to protect against removal
        p, err := store.Get(name, metricsPluginType, plugingetter.Lookup)
        if err != nil {
            return
        }

        adapter, err := makePluginAdapter(p)
        if err != nil {
            log.G(context.TODO()).WithError(err).WithField("plugin", p.Name()).Error("Error creating plugin adapter")
        }
        if err := adapter.StartMetrics(); err != nil {
            log.G(context.TODO()).WithError(err).WithField("plugin", p.Name()).Error("Error starting metrics collector plugin")
        }
    })
}