Service: Select consensus on "init" (not on "daemon")

Fixes #865.

This makes the necessary changes so that consensu is selected on "init" with a
flag set, by default, to "crdt". This generates only a "crdt" or a "raft"
section, not both.

If the configuration file has a "raft" section, "raft" will be used to start
the daemon. If it has a "crdt" section, "crdt" will be used. If it has none or
both sections, an error will happen.

This also affects "state *" commands, which will now autoselect how to work
from the existing configuration.

Dockerfile

@@ -57,4 +57,4 @@ VOLUME $IPFS_CLUSTER_PATH
 ENTRYPOINT ["/sbin/tini", "--", "/usr/local/bin/entrypoint.sh"]
 
 # Defaults for ipfs-cluster-service go here
-CMD ["daemon", "--consensus raft"]
+CMD ["daemon"]

Dockerfile-test

@@ -58,4 +58,4 @@ VOLUME $IPFS_CLUSTER_PATH
 ENTRYPOINT ["/usr/local/bin/start-daemons.sh"]
 
 # Defaults would go here
-CMD ["daemon", "--upgrade"]
+CMD ["daemon"]

cmd/ipfs-cluster-service/daemon.go

@@ -46,10 +46,6 @@ func parseBootstraps(flagVal []string) (bootstraps []ma.Multiaddr) {
 
 // Runs the cluster peer
 func daemon(c *cli.Context) error {
-	if c.String("consensus") == "" {
-		checkErr("starting daemon", errors.New("--consensus flag must be set to \"raft\" or \"crdt\""))
-	}
-
 	logger.Info("Initializing. For verbose output run with \"-l debug\". Please wait...")
 
 	ctx, cancel := context.WithCancel(context.Background())
@@ -78,7 +74,7 @@ func daemon(c *cli.Context) error {
 
 	// Cleanup state if bootstrapping
 	raftStaging := false
-	if len(bootstraps) > 0 && c.String("consensus") == "raft" {
+	if len(bootstraps) > 0 && cfgHelper.GetConsensus() == cfgs.Raft.ConfigKey() {
 		raft.CleanupRaft(cfgs.Raft)
 		raftStaging = true
 	}
@@ -159,14 +155,13 @@ func createCluster(
 	tracer, err := observations.SetupTracing(cfgs.Tracing)
 	checkErr("setting up Tracing", err)
 
-	store := setupDatastore(c.String("consensus"), cfgHelper.Identity(), cfgs)
+	store := setupDatastore(cfgHelper)
 
 	cons, err := setupConsensus(
-		c.String("consensus"),
+		cfgHelper,
 		host,
 		dht,
 		pubsub,
-		cfgs,
 		store,
 		raftStaging,
 	)
@@ -176,7 +171,7 @@ func createCluster(
 	}
 
 	var peersF func(context.Context) ([]peer.ID, error)
-	if c.String("consensus") == "raft" {
+	if cfgHelper.GetConsensus() == cfgs.Raft.ConfigKey() {
 		peersF = cons.Peers
 	}
 
@@ -293,45 +288,42 @@ func setupPinTracker(
 	}
 }
 
-func setupDatastore(
-	consensus string,
-	ident *config.Identity,
-	cfgs *cmdutils.Configs,
-) ds.Datastore {
-	stmgr, err := cmdutils.NewStateManager(consensus, ident, cfgs)
+func setupDatastore(cfgHelper *cmdutils.ConfigHelper) ds.Datastore {
+	stmgr, err := cmdutils.NewStateManager(cfgHelper.GetConsensus(), cfgHelper.Identity(), cfgHelper.Configs())
 	checkErr("creating state manager", err)
 	store, err := stmgr.GetStore()
 	checkErr("creating datastore", err)
 	return store
 }
 
 func setupConsensus(
-	name string,
+	cfgHelper *cmdutils.ConfigHelper,
 	h host.Host,
 	dht *dht.IpfsDHT,
 	pubsub *pubsub.PubSub,
-	cfgs *cmdutils.Configs,
 	store ds.Datastore,
 	raftStaging bool,
 ) (ipfscluster.Consensus, error) {
-	switch name {
-	case "raft":
+
+	cfgs := cfgHelper.Configs()
+	switch cfgHelper.GetConsensus() {
+	case cfgs.Raft.ConfigKey():
 		rft, err := raft.NewConsensus(
 			h,
-			cfgs.Raft,
+			cfgHelper.Configs().Raft,
 			store,
 			raftStaging,
 		)
 		if err != nil {
 			return nil, errors.Wrap(err, "creating Raft component")
 		}
 		return rft, nil
-	case "crdt":
+	case cfgs.Crdt.ConfigKey():
 		convrdt, err := crdt.New(
 			h,
 			dht,
 			pubsub,
-			cfgs.Crdt,
+			cfgHelper.Configs().Crdt,
 			store,
 		)
 		if err != nil {

cmd/ipfs-cluster-service/lock.go

@@ -29,7 +29,7 @@ func (l *lock) lock() {
 	}
 
 	// we should have a config folder whenever we try to lock
-	cfgHelper := cmdutils.NewConfigHelper(configPath, identityPath)
+	cfgHelper := cmdutils.NewConfigHelper(configPath, identityPath, "")
 	cfgHelper.MakeConfigFolder()
 
 	// set the lock file within this function

cmd/ipfs-cluster-service/main.go

@@ -4,6 +4,7 @@ package main
 import (
 	"bufio"
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -30,6 +31,7 @@ const programName = `ipfs-cluster-service`
 const (
 	defaultPinTracker = "map"
 	defaultLogLevel   = "info"
+	defaultConsensus  = "crdt"
 )
 
 const (
@@ -221,26 +223,30 @@ func main() {
 This command will initialize a new %s configuration file and, if it
 does already exist, generate a new %s for %s.
 
-If the optional [source-url] is given, the generated configuration file 
+If the optional [source-url] is given, the generated configuration file
 will refer to it. The source configuration will be fetched from its source
 URL during the launch of the daemon. If not, a default standard configuration
 file will be created.
 
-In the latter case, a cluster secret will be generated as required by %s.
-Alternatively, this secret can be manually provided with --custom-secret (in
-which case it will be prompted), or by setting the CLUSTER_SECRET environment
-variable.
+In the latter case, a cluster secret will be generated as required
+by %s. Alternatively, this secret can be manually
+provided with --custom-secret (in which case it will be prompted), or
+by setting the CLUSTER_SECRET environment variable.
+
+The --consensus flag allows to select an alternative consensus components for
+in the newly-generated configuration.
 
 Note that the --force flag allows to overwrite an existing
 configuration with default values. To generate a new identity, please
 remove the %s file first and clean any Raft state.
 
 By default, an empty peerstore file will be created too. Initial contents can
-be provided with the -peers flag. In this case, the "trusted_peers" list in
-the "crdt" configuration section and the "init_peerset" list in the "raft"
-configuration section will be prefilled to the peer IDs in the given
-multiaddresses.
+be provided with the --peers flag. Depending on the chosen consensus, the
+"trusted_peers" list in the "crdt" configuration section and the
+"init_peerset" list in the "raft" configuration section will be prefilled to
+the peer IDs in the given multiaddresses.
 `,
+
 				DefaultConfigFile,
 				DefaultIdentityFile,
 				programName,
@@ -249,6 +255,11 @@ multiaddresses.
 			),
 			ArgsUsage: "[http-source-url]",
 			Flags: []cli.Flag{
+				cli.StringFlag{
+					Name:  "consensus",
+					Usage: "select consensus component: 'crdt' or 'raft'",
+					Value: defaultConsensus,
+				},
 				cli.BoolFlag{
 					Name:  "custom-secret, s",
 					Usage: "prompt for the cluster secret (when no source specified)",
@@ -263,7 +274,12 @@ multiaddresses.
 				},
 			},
 			Action: func(c *cli.Context) error {
-				cfgHelper := cmdutils.NewConfigHelper(configPath, identityPath)
+				consensus := c.String("consensus")
+				if consensus != "raft" && consensus != "crdt" {
+					checkErr("choosing consensus", errors.New("flag value must be set to 'raft' or 'crdt'"))
+				}
+
+				cfgHelper := cmdutils.NewConfigHelper(configPath, identityPath, consensus)
 				defer cfgHelper.Manager().Shutdown() // wait for saves
 
 				configExists := false
@@ -375,10 +391,6 @@ multiaddresses.
 					Usage:  "remove peer from cluster on exit. Overrides \"leave_on_shutdown\"",
 					Hidden: true,
 				},
-				cli.StringFlag{
-					Name:  "consensus",
-					Usage: "shared state management provider [raft,crdt]",
-				},
 				cli.StringFlag{
 					Name:   "pintracker",
 					Value:  defaultPinTracker,
@@ -418,16 +430,12 @@ By default, the state will be printed to stdout.
 							Value: "",
 							Usage: "writes to an output file",
 						},
-						cli.StringFlag{
-							Name:  "consensus",
-							Usage: "consensus component to export data from [raft, crdt]",
-						},
 					},
 					Action: func(c *cli.Context) error {
 						locker.lock()
 						defer locker.tryUnlock()
 
-						mgr := getStateManager(c.String("consensus"))
+						mgr := getStateManager()
 
 						var w io.WriteCloser
 						var err error
@@ -463,10 +471,6 @@ to import. If no argument is provided, stdin will be used.
 							Name:  "force, f",
 							Usage: "skips confirmation prompt",
 						},
-						cli.StringFlag{
-							Name:  "consensus",
-							Usage: "consensus component to export data from [raft, crdt]",
-						},
 					},
 					Action: func(c *cli.Context) error {
 						locker.lock()
@@ -478,7 +482,7 @@ to import. If no argument is provided, stdin will be used.
 							return nil
 						}
 
-						mgr := getStateManager(c.String("consensus"))
+						mgr := getStateManager()
 
 						// Get the importing file path
 						importFile := c.Args().First()
@@ -511,10 +515,6 @@ to all effects. Peers may need to bootstrap and sync from scratch after this.
 							Name:  "force, f",
 							Usage: "skip confirmation prompt",
 						},
-						cli.StringFlag{
-							Name:  "consensus",
-							Usage: "consensus component to export data from [raft, crdt]",
-						},
 					},
 					Action: func(c *cli.Context) error {
 						locker.lock()
@@ -528,7 +528,7 @@ to all effects. Peers may need to bootstrap and sync from scratch after this.
 							return nil
 						}
 
-						mgr := getStateManager(c.String("consensus"))
+						mgr := getStateManager()
 						checkErr("cleaning state", mgr.Clean())
 						logger.Info("data correctly cleaned up")
 						return nil
@@ -608,21 +608,21 @@ func yesNoPrompt(prompt string) bool {
 
 func loadConfigHelper() *cmdutils.ConfigHelper {
 	// Load all the configurations and identity
-	cfgHelper := cmdutils.NewConfigHelper(configPath, identityPath)
+	cfgHelper := cmdutils.NewConfigHelper(configPath, identityPath, "")
 	err := cfgHelper.LoadFromDisk()
 	checkErr("loading identity or configurations", err)
 	return cfgHelper
 }
 
-func getStateManager(consensus string) cmdutils.StateManager {
+func getStateManager() cmdutils.StateManager {
 	cfgHelper := loadConfigHelper()
 	// since we won't save configs we can shutdown
 	cfgHelper.Manager().Shutdown()
 	mgr, err := cmdutils.NewStateManager(
-		consensus,
+		cfgHelper.GetConsensus(),
 		cfgHelper.Identity(),
 		cfgHelper.Configs(),
 	)
-	checkErr("creating state manager,", err)
+	checkErr("creating state manager", err)
 	return mgr
 }

cmdutils/configs.go

@@ -50,14 +50,16 @@ type ConfigHelper struct {
 
 	configPath   string
 	identityPath string
+	consensus    string
 }
 
 // NewConfigHelper creates a config helper given the paths to the
 // configuration and identity files.
-func NewConfigHelper(configPath, identityPath string) *ConfigHelper {
+func NewConfigHelper(configPath, identityPath, consensus string) *ConfigHelper {
 	ch := &ConfigHelper{
 		configPath:   configPath,
 		identityPath: identityPath,
+		consensus:    consensus,
 	}
 	ch.init()
 	return ch
@@ -138,6 +140,29 @@ func (ch *ConfigHelper) Configs() *Configs {
 	return ch.configs
 }
 
+// GetConsensus attempts to return the configured consensus.
+// If the ConfigHelper was initialized with a consensus string
+// then it returns that.
+//
+// Otherwise it checks whether one of the consensus configurations
+// has been loaded. If both or non have been loaded, it returns
+// an empty string.
+func (ch *ConfigHelper) GetConsensus() string {
+	if ch.consensus != "" {
+		return ch.consensus
+	}
+	crdtLoaded := ch.manager.IsLoadedFromJSON(config.Consensus, ch.configs.Crdt.ConfigKey())
+	raftLoaded := ch.manager.IsLoadedFromJSON(config.Consensus, ch.configs.Raft.ConfigKey())
+	if crdtLoaded == raftLoaded { //both loaded or none
+		return ""
+	}
+
+	if crdtLoaded {
+		return ch.configs.Crdt.ConfigKey()
+	}
+	return ch.configs.Raft.ConfigKey()
+}
+
 // register all current cluster components
 func (ch *ConfigHelper) init() {
 	man := config.NewManager()
@@ -160,8 +185,6 @@ func (ch *ConfigHelper) init() {
 	man.RegisterComponent(config.API, cfgs.Restapi)
 	man.RegisterComponent(config.API, cfgs.Ipfsproxy)
 	man.RegisterComponent(config.IPFSConn, cfgs.Ipfshttp)
-	man.RegisterComponent(config.Consensus, cfgs.Raft)
-	man.RegisterComponent(config.Consensus, cfgs.Crdt)
 	man.RegisterComponent(config.PinTracker, cfgs.Maptracker)
 	man.RegisterComponent(config.PinTracker, cfgs.Statelesstracker)
 	man.RegisterComponent(config.Monitor, cfgs.Pubsubmon)
@@ -170,6 +193,16 @@ func (ch *ConfigHelper) init() {
 	man.RegisterComponent(config.Observations, cfgs.Tracing)
 	man.RegisterComponent(config.Datastore, cfgs.Badger)
 
+	switch ch.consensus {
+	case cfgs.Raft.ConfigKey():
+		man.RegisterComponent(config.Consensus, cfgs.Raft)
+	case cfgs.Crdt.ConfigKey():
+		man.RegisterComponent(config.Consensus, cfgs.Crdt)
+	default:
+		man.RegisterComponent(config.Consensus, cfgs.Raft)
+		man.RegisterComponent(config.Consensus, cfgs.Crdt)
+	}
+
 	ch.identity = &config.Identity{}
 	ch.manager = man
 	ch.configs = cfgs

cmdutils/state.go

@@ -33,12 +33,12 @@ type StateManager interface {
 // consensus ("raft" or "crdt"). It will need initialized configs.
 func NewStateManager(consensus string, ident *config.Identity, cfgs *Configs) (StateManager, error) {
 	switch consensus {
-	case "raft":
+	case cfgs.Raft.ConfigKey():
 		return &raftStateManager{ident, cfgs}, nil
-	case "crdt":
+	case cfgs.Crdt.ConfigKey():
 		return &crdtStateManager{ident, cfgs}, nil
 	case "":
-		return nil, errors.New("unspecified consensus component")
+		return nil, errors.New("could not determine the consensus component")
 	default:
 		return nil, fmt.Errorf("unknown consensus component '%s'", consensus)
 	}

config/config.go

@@ -423,7 +423,7 @@ func (cfg *Manager) LoadJSON(bs []byte) error {
 			logger.Debugf("%s component configuration loaded", name)
 		} else {
 			cfg.undefinedComps[t][name] = true
-			logger.Warningf("%s component is empty, generating default", name)
+			logger.Debugf("%s component is empty, generating default", name)
 			component.Default()
 		}