fleet.go

/*
   Copyright 2014 CoreOS, Inc.

   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 main

import (
	"encoding/json"
	"flag"
	"fmt"
	"os"
	"os/signal"
	"strings"
	"syscall"

	"github.com/coreos/fleet/Godeps/_workspace/src/github.com/rakyll/globalconf"

	"github.com/coreos/fleet/agent"
	"github.com/coreos/fleet/config"
	"github.com/coreos/fleet/log"
	"github.com/coreos/fleet/registry"
	"github.com/coreos/fleet/server"
	"github.com/coreos/fleet/version"
)

const (
	DefaultConfigFile = "/etc/fleet/fleet.conf"
)

func main() {
	userset := flag.NewFlagSet("fleet", flag.ExitOnError)
	printVersion := userset.Bool("version", false, "Print the version and exit")
	cfgPath := userset.String("config", "", fmt.Sprintf("Path to config file. Fleet will look for a config at %s by default.", DefaultConfigFile))

	err := userset.Parse(os.Args[1:])
	if err == flag.ErrHelp {
		userset.Usage()
		os.Exit(1)
	}

	if *printVersion {
		fmt.Println("fleetd version", version.Version)
		os.Exit(0)
	}

	log.Infof("Starting fleetd version %v", version.Version)

	cfgset := flag.NewFlagSet("fleet", flag.ExitOnError)
	cfgset.Int("verbosity", 0, "Logging level")
	cfgset.Var(&stringSlice{}, "etcd_servers", "List of etcd endpoints")
	cfgset.String("etcd_keyfile", "", "SSL key file used to secure etcd communication")
	cfgset.String("etcd_certfile", "", "SSL certification file used to secure etcd communication")
	cfgset.String("etcd_cafile", "", "SSL Certificate Authority file used to secure etcd communication")
	cfgset.String("etcd_key_prefix", registry.DefaultKeyPrefix, "Keyspace for fleet data in etcd")
	cfgset.Float64("etcd_request_timeout", 1.0, "Amount of time in seconds to allow a single etcd request before considering it failed.")
	cfgset.Float64("engine_reconcile_interval", 2.0, "Interval at which the engine should reconcile the cluster schedule in etcd.")
	cfgset.String("public_ip", "", "IP address that fleet machine should publish")
	cfgset.String("metadata", "", "List of key-value metadata to assign to the fleet machine")
	cfgset.String("agent_ttl", agent.DefaultTTL, "TTL in seconds of fleet machine state in etcd")
	cfgset.Bool("verify_units", false, "DEPRECATED - This option is ignored")
	cfgset.String("authorized_keys_file", "", "DEPRECATED - This option is ignored")

	globalconf.Register("", cfgset)
	cfg, err := getConfig(cfgset, *cfgPath)
	if err != nil {
		log.Fatalf(err.Error())
	}

	log.V(1).Infof("Creating Server")
	srv, err := server.New(*cfg)
	if err != nil {
		log.Fatalf("Failed creating Server: %v", err.Error())
	}
	srv.Run()

	reconfigure := func() {
		log.Infof("Reloading configuration from %s", *cfgPath)

		cfg, err := getConfig(cfgset, *cfgPath)
		if err != nil {
			log.Fatalf(err.Error())
		}

		log.Infof("Restarting server components")
		srv.Stop()

		srv, err = server.New(*cfg)
		if err != nil {
			log.Fatalf(err.Error())
		}
		srv.Run()
	}

	shutdown := func() {
		log.Infof("Gracefully shutting down")
		srv.Stop()
		srv.Purge()
		os.Exit(0)
	}

	writeState := func() {
		log.Infof("Dumping server state")

		encoded, err := json.Marshal(srv)
		if err != nil {
			log.Errorf("Failed to dump server state: %v", err)
			return
		}

		if _, err := os.Stdout.Write(encoded); err != nil {
			log.Errorf("Failed to dump server state: %v", err)
			return
		}

		os.Stdout.Write([]byte("\n"))

		log.V(1).Infof("Finished dumping server state")
	}

	signals := map[os.Signal]func(){
		syscall.SIGHUP:  reconfigure,
		syscall.SIGTERM: shutdown,
		syscall.SIGINT:  shutdown,
		syscall.SIGUSR1: writeState,
	}

	listenForSignals(signals)
}

func getConfig(flagset *flag.FlagSet, userCfgFile string) (*config.Config, error) {
	opts := globalconf.Options{EnvPrefix: "FLEET_"}

	if userCfgFile != "" {
		// Fail hard if a user-provided config is not usable
		fi, err := os.Stat(userCfgFile)
		if err != nil {
			log.Fatalf("Unable to use config file %s: %v", userCfgFile, err)
		}
		if fi.IsDir() {
			log.Fatalf("Provided config %s is a directory, not a file", userCfgFile)
		}

		log.Infof("Using provided config file %s", userCfgFile)
		opts.Filename = userCfgFile

	} else if _, err := os.Stat(DefaultConfigFile); err == nil {
		log.Infof("Using default config file %s", DefaultConfigFile)
		opts.Filename = DefaultConfigFile
	} else {
		log.Infof("No provided or default config file found - proceeding without")
	}

	gconf, err := globalconf.NewWithOptions(&opts)
	if err != nil {
		return nil, err
	}

	gconf.ParseSet("", flagset)

	cfg := config.Config{
		Verbosity:               (*flagset.Lookup("verbosity")).Value.(flag.Getter).Get().(int),
		EtcdServers:             (*flagset.Lookup("etcd_servers")).Value.(flag.Getter).Get().(stringSlice),
		EtcdKeyPrefix:           (*flagset.Lookup("etcd_key_prefix")).Value.(flag.Getter).Get().(string),
		EtcdKeyFile:             (*flagset.Lookup("etcd_keyfile")).Value.(flag.Getter).Get().(string),
		EtcdCertFile:            (*flagset.Lookup("etcd_certfile")).Value.(flag.Getter).Get().(string),
		EtcdCAFile:              (*flagset.Lookup("etcd_cafile")).Value.(flag.Getter).Get().(string),
		EtcdRequestTimeout:      (*flagset.Lookup("etcd_request_timeout")).Value.(flag.Getter).Get().(float64),
		EngineReconcileInterval: (*flagset.Lookup("engine_reconcile_interval")).Value.(flag.Getter).Get().(float64),
		PublicIP:                (*flagset.Lookup("public_ip")).Value.(flag.Getter).Get().(string),
		RawMetadata:             (*flagset.Lookup("metadata")).Value.(flag.Getter).Get().(string),
		AgentTTL:                (*flagset.Lookup("agent_ttl")).Value.(flag.Getter).Get().(string),
		VerifyUnits:             (*flagset.Lookup("verify_units")).Value.(flag.Getter).Get().(bool),
		AuthorizedKeysFile:      (*flagset.Lookup("authorized_keys_file")).Value.(flag.Getter).Get().(string),
	}

	if cfg.VerifyUnits {
		log.Error("Config option verify_units is no longer supported - ignoring")
	}
	if len(cfg.AuthorizedKeysFile) > 0 {
		log.Error("Config option authorized_keys_file is no longer supported - ignoring")
	}

	log.SetVerbosity(cfg.Verbosity)
	return &cfg, nil
}

func listenForSignals(sigmap map[os.Signal]func()) {
	sigchan := make(chan os.Signal, 1)

	for k := range sigmap {
		signal.Notify(sigchan, k)
	}

	for true {
		sig := <-sigchan
		handler, ok := sigmap[sig]
		if ok {
			handler()
		}
	}
}

type stringSlice []string

func (f *stringSlice) Set(value string) error {
	for _, item := range strings.Split(value, ",") {
		item = strings.TrimLeft(item, " [\"")
		item = strings.TrimRight(item, " \"]")
		*f = append(*f, item)
	}

	return nil
}

func (f *stringSlice) String() string {
	return fmt.Sprintf("%v", *f)
}

func (f *stringSlice) Value() []string {
	return *f
}

func (f *stringSlice) Get() interface{} {
	return *f
}