traces/modules/backendworker/backendworker_ring.go

package backendworker

import (
	"flag"
	"os"
	"time"

	"github.com/go-kit/log/level"
	"github.com/grafana/dskit/flagext"
	"github.com/grafana/dskit/kv"
	"github.com/grafana/dskit/ring"

	util_log "github.com/grafana/tempo/pkg/util/log"
)

// RingConfig masks the ring lifecycler config which contains
// many options not really required by the worker's ring. This config
// is used to strip down the config to the minimum, and avoid confusion
// to the user.
type RingConfig struct {
	KVStore          kv.Config     `yaml:"kvstore"`
	HeartbeatPeriod  time.Duration `yaml:"heartbeat_period"`
	HeartbeatTimeout time.Duration `yaml:"heartbeat_timeout"`

	// Wait ring stability.
	WaitStabilityMinDuration time.Duration `yaml:"wait_stability_min_duration"`
	WaitStabilityMaxDuration time.Duration `yaml:"wait_stability_max_duration"`

	// Instance details
	InstanceID             string   `yaml:"instance_id" doc:"hidden"`
	InstanceInterfaceNames []string `yaml:"instance_interface_names"`
	InstancePort           int      `yaml:"instance_port" doc:"hidden"`
	InstanceAddr           string   `yaml:"instance_addr" doc:"hidden"`
	EnableInet6            bool     `yaml:"enable_inet6"`

	// Injected internally
	ListenPort int `yaml:"-"`

	WaitActiveInstanceTimeout time.Duration `yaml:"wait_active_instance_timeout"`

	ObservePeriod time.Duration `yaml:"-"`
}

// RegisterFlags adds the flags required to config this to the given FlagSet
func (cfg *RingConfig) RegisterFlags(f *flag.FlagSet) {
	hostname, err := os.Hostname()
	if err != nil {
		level.Error(util_log.Logger).Log("msg", "failed to get hostname", "err", err)
		os.Exit(1)
	}

	// Ring flags
	cfg.KVStore.RegisterFlagsWithPrefix("worker.ring.", "collectors/", f)
	f.DurationVar(&cfg.HeartbeatPeriod, "worker.ring.heartbeat-period", 5*time.Second, "Period at which to heartbeat to the ring. 0 = disabled.")
	f.DurationVar(&cfg.HeartbeatTimeout, "worker.ring.heartbeat-timeout", time.Minute, "The heartbeat timeout after which workers are considered unhealthy within the ring. 0 = never (timeout disabled).")

	// Wait stability flags.
	f.DurationVar(&cfg.WaitStabilityMinDuration, "worker.ring.wait-stability-min-duration", time.Minute, "Minimum time to wait for ring stability at startup. 0 to disable.")
	f.DurationVar(&cfg.WaitStabilityMaxDuration, "worker.ring.wait-stability-max-duration", 5*time.Minute, "Maximum time to wait for ring stability at startup. If the backend-worker ring keeps changing after this period of time, the backend-worker will start anyway.")

	// Instance flags
	cfg.InstanceInterfaceNames = []string{"eth0", "en0"}
	f.Var((*flagext.StringSlice)(&cfg.InstanceInterfaceNames), "worker.ring.instance-interface-names", "Name of network interface to read address from.")
	f.StringVar(&cfg.InstanceAddr, "worker.ring.instance-addr", "", "IP address to advertise in the ring.")
	f.IntVar(&cfg.InstancePort, "worker.ring.instance-port", 0, "Port to advertise in the ring (defaults to server.grpc-listen-port).")
	f.StringVar(&cfg.InstanceID, "worker.ring.instance-id", hostname, "Instance ID to register in the ring.")

	// Timeout durations
	f.DurationVar(&cfg.WaitActiveInstanceTimeout, "worker.ring.wait-active-instance-timeout", 10*time.Minute, "Timeout for waiting on backend-worker to become ACTIVE in the ring.")
}

// ToLifecyclerConfig returns a LifecyclerConfig based on the backend-worker
// ring config.
func (cfg *RingConfig) ToLifecyclerConfig() ring.LifecyclerConfig {
	// We have to make sure that the ring.LifecyclerConfig and ring.Config
	// defaults are preserved
	lc := ring.LifecyclerConfig{}
	rc := ring.Config{}

	flagext.DefaultValues(&lc)
	flagext.DefaultValues(&rc)

	// Configure ring
	rc.KVStore = cfg.KVStore
	rc.HeartbeatTimeout = cfg.HeartbeatTimeout
	rc.ReplicationFactor = 1

	// Configure lifecycler
	lc.RingConfig = rc
	lc.RingConfig.SubringCacheDisabled = true
	lc.ListenPort = cfg.ListenPort
	lc.Addr = cfg.InstanceAddr
	lc.Port = cfg.InstancePort
	lc.ID = cfg.InstanceID
	lc.InfNames = cfg.InstanceInterfaceNames
	lc.UnregisterOnShutdown = true
	lc.HeartbeatPeriod = cfg.HeartbeatPeriod
	lc.ObservePeriod = cfg.ObservePeriod
	lc.JoinAfter = 0
	lc.MinReadyDuration = 0
	lc.FinalSleep = 0

	// We use a safe default instead of exposing to config option to the user
	// in order to simplify the config.
	lc.NumTokens = 512

	return lc
}