Merge pull request etcd-io#5925 from heyitsanthony/embed-etcdmain

embeddable etcdmain

Documentation/docs.md

@@ -14,6 +14,7 @@ The easiest way to get started using etcd as a distributed key-value store is to
  - [Interacting with etcd][interacting]
  - [API references][api_ref]
  - [gRPC gateway][api_grpc_gateway]
+ - [Embedding etcd][embed_etcd]
  - [Experimental features and APIs][experimental]
 
 ## Operating etcd clusters
@@ -56,6 +57,7 @@ To learn more about the concepts and internals behind etcd, read the following p
 [data_model]: learning/data_model.md
 [demo]: demo.md
 [download_build]: dl_build.md
+[embed_etcd]: ../embed/
 [failures]: op-guide/failures.md
 [glossary]: learning/glossary.md
 [interacting]: dev-guide/interacting_v3.md

embed/config.go

@@ -0,0 +1,304 @@
+// Copyright 2016 The etcd 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 embed
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net/url"
+	"strings"
+
+	"github.com/coreos/etcd/discovery"
+	"github.com/coreos/etcd/etcdserver"
+	"github.com/coreos/etcd/pkg/cors"
+	"github.com/coreos/etcd/pkg/transport"
+	"github.com/coreos/etcd/pkg/types"
+	"github.com/ghodss/yaml"
+)
+
+const (
+	ClusterStateFlagNew      = "new"
+	ClusterStateFlagExisting = "existing"
+
+	DefaultName                     = "default"
+	DefaultInitialAdvertisePeerURLs = "http://localhost:2380"
+	DefaultAdvertiseClientURLs      = "http://localhost:2379"
+	DefaultListenPeerURLs           = "http://localhost:2380"
+	DefaultListenClientURLs         = "http://localhost:2379"
+	DefaultMaxSnapshots             = 5
+	DefaultMaxWALs                  = 5
+
+	// maxElectionMs specifies the maximum value of election timeout.
+	// More details are listed in ../Documentation/tuning.md#time-parameters.
+	maxElectionMs = 50000
+)
+
+var (
+	ErrConflictBootstrapFlags = fmt.Errorf("multiple discovery or bootstrap flags are set. " +
+		"Choose one of \"initial-cluster\", \"discovery\" or \"discovery-srv\"")
+	ErrUnsetAdvertiseClientURLsFlag = fmt.Errorf("--advertise-client-urls is required when --listen-client-urls is set explicitly")
+)
+
+// Config holds the arguments for configuring an etcd server.
+type Config struct {
+	// member
+
+	CorsInfo                *cors.CORSInfo
+	LPUrls, LCUrls          []url.URL
+	Dir                     string `json:"data-dir"`
+	WalDir                  string `json:"wal-dir"`
+	MaxSnapFiles            uint   `json:"max-snapshots"`
+	MaxWalFiles             uint   `json:"max-wals"`
+	Name                    string `json:"name"`
+	SnapCount               uint64 `json:"snapshot-count"`
+	AutoCompactionRetention int    `json:"auto-compaction-retention"`
+
+	// TickMs is the number of milliseconds between heartbeat ticks.
+	// TODO: decouple tickMs and heartbeat tick (current heartbeat tick = 1).
+	// make ticks a cluster wide configuration.
+	TickMs            uint  `json:"heartbeat-interval"`
+	ElectionMs        uint  `json:"election-timeout"`
+	QuotaBackendBytes int64 `json:"quota-backend-bytes"`
+
+	// clustering
+
+	APUrls, ACUrls      []url.URL
+	ClusterState        string `json:"initial-cluster-state"`
+	DNSCluster          string `json:"discovery-srv"`
+	Dproxy              string `json:"discovery-proxy"`
+	Durl                string `json:"discovery"`
+	InitialCluster      string `json:"initial-cluster"`
+	InitialClusterToken string `json:"initial-cluster-token"`
+	StrictReconfigCheck bool   `json:"strict-reconfig-check"`
+
+	// security
+
+	ClientTLSInfo transport.TLSInfo
+	ClientAutoTLS bool
+	PeerTLSInfo   transport.TLSInfo
+	PeerAutoTLS   bool
+
+	// debug
+
+	Debug        bool   `json:"debug"`
+	LogPkgLevels string `json:"log-package-levels"`
+	EnablePprof  bool
+
+	// ForceNewCluster starts a new cluster even if previously started; unsafe.
+	ForceNewCluster bool `json:"force-new-cluster"`
+}
+
+// configYAML holds the config suitable for yaml parsing
+type configYAML struct {
+	Config
+	configJSON
+}
+
+// configJSON has file options that are translated into Config options
+type configJSON struct {
+	LPUrlsJSON         string         `json:"listen-peer-urls"`
+	LCUrlsJSON         string         `json:"listen-client-urls"`
+	CorsJSON           string         `json:"cors"`
+	APUrlsJSON         string         `json:"initial-advertise-peer-urls"`
+	ACUrlsJSON         string         `json:"advertise-client-urls"`
+	ClientSecurityJSON securityConfig `json:"client-transport-security"`
+	PeerSecurityJSON   securityConfig `json:"peer-transport-security"`
+}
+
+type securityConfig struct {
+	CAFile        string `json:"ca-file"`
+	CertFile      string `json:"cert-file"`
+	KeyFile       string `json:"key-file"`
+	CertAuth      bool   `json:"client-cert-auth"`
+	TrustedCAFile string `json:"trusted-ca-file"`
+	AutoTLS       bool   `json:"auto-tls"`
+}
+
+// NewConfig creates a new Config populated with default values.
+func NewConfig() *Config {
+	apurl, _ := url.Parse(DefaultInitialAdvertisePeerURLs)
+	acurl, _ := url.Parse(DefaultAdvertiseClientURLs)
+	cfg := &Config{
+		CorsInfo:            &cors.CORSInfo{},
+		MaxSnapFiles:        DefaultMaxSnapshots,
+		MaxWalFiles:         DefaultMaxWALs,
+		Name:                DefaultName,
+		SnapCount:           etcdserver.DefaultSnapCount,
+		TickMs:              100,
+		ElectionMs:          1000,
+		APUrls:              []url.URL{*apurl},
+		ACUrls:              []url.URL{*acurl},
+		ClusterState:        ClusterStateFlagNew,
+		InitialClusterToken: "etcd-cluster",
+	}
+	cfg.InitialCluster = cfg.InitialClusterFromName(cfg.Name)
+	return cfg
+}
+
+func ConfigFromFile(path string) (*Config, error) {
+	cfg := &configYAML{}
+	if err := cfg.configFromFile(path); err != nil {
+		return nil, err
+	}
+	return &cfg.Config, nil
+}
+
+func (cfg *configYAML) configFromFile(path string) error {
+	b, err := ioutil.ReadFile(path)
+	if err != nil {
+		return err
+	}
+
+	err = yaml.Unmarshal(b, cfg)
+	if err != nil {
+		return err
+	}
+
+	if cfg.LPUrlsJSON != "" {
+		u, err := types.NewURLs(strings.Split(cfg.LPUrlsJSON, ","))
+		if err != nil {
+			plog.Fatalf("unexpected error setting up listen-peer-urls: %v", err)
+		}
+		cfg.LPUrls = []url.URL(u)
+	}
+
+	if cfg.LCUrlsJSON != "" {
+		u, err := types.NewURLs(strings.Split(cfg.LCUrlsJSON, ","))
+		if err != nil {
+			plog.Fatalf("unexpected error setting up listen-client-urls: %v", err)
+		}
+		cfg.LCUrls = []url.URL(u)
+	}
+
+	if cfg.CorsJSON != "" {
+		if err := cfg.CorsInfo.Set(cfg.CorsJSON); err != nil {
+			plog.Panicf("unexpected error setting up cors: %v", err)
+		}
+	}
+
+	if cfg.APUrlsJSON != "" {
+		u, err := types.NewURLs(strings.Split(cfg.APUrlsJSON, ","))
+		if err != nil {
+			plog.Fatalf("unexpected error setting up initial-advertise-peer-urls: %v", err)
+		}
+		cfg.APUrls = []url.URL(u)
+	}
+
+	if cfg.ACUrlsJSON != "" {
+		u, err := types.NewURLs(strings.Split(cfg.ACUrlsJSON, ","))
+		if err != nil {
+			plog.Fatalf("unexpected error setting up advertise-peer-urls: %v", err)
+		}
+		cfg.ACUrls = []url.URL(u)
+	}
+
+	if cfg.ClusterState == "" {
+		cfg.ClusterState = ClusterStateFlagNew
+	}
+
+	copySecurityDetails := func(tls *transport.TLSInfo, ysc *securityConfig) {
+		tls.CAFile = ysc.CAFile
+		tls.CertFile = ysc.CertFile
+		tls.KeyFile = ysc.KeyFile
+		tls.ClientCertAuth = ysc.CertAuth
+		tls.TrustedCAFile = ysc.TrustedCAFile
+	}
+	copySecurityDetails(&cfg.ClientTLSInfo, &cfg.ClientSecurityJSON)
+	copySecurityDetails(&cfg.PeerTLSInfo, &cfg.PeerSecurityJSON)
+	cfg.ClientAutoTLS = cfg.ClientSecurityJSON.AutoTLS
+	cfg.PeerAutoTLS = cfg.PeerSecurityJSON.AutoTLS
+
+	return cfg.Validate()
+}
+
+func (cfg *Config) Validate() error {
+	// Check if conflicting flags are passed.
+	nSet := 0
+	for _, v := range []bool{cfg.Durl != "", cfg.InitialCluster != "", cfg.DNSCluster != ""} {
+		if v {
+			nSet++
+		}
+	}
+
+	if cfg.ClusterState != ClusterStateFlagNew && cfg.ClusterState != ClusterStateFlagExisting {
+		return fmt.Errorf("unexpected clusterState %q", cfg.ClusterState)
+	}
+
+	if nSet > 1 {
+		return ErrConflictBootstrapFlags
+	}
+
+	if 5*cfg.TickMs > cfg.ElectionMs {
+		return fmt.Errorf("--election-timeout[%vms] should be at least as 5 times as --heartbeat-interval[%vms]", cfg.ElectionMs, cfg.TickMs)
+	}
+	if cfg.ElectionMs > maxElectionMs {
+		return fmt.Errorf("--election-timeout[%vms] is too long, and should be set less than %vms", cfg.ElectionMs, maxElectionMs)
+	}
+
+	// check this last since proxying in etcdmain may make this OK
+	if cfg.LCUrls != nil && cfg.ACUrls == nil {
+		return ErrUnsetAdvertiseClientURLsFlag
+	}
+
+	return nil
+}
+
+// PeerURLsMapAndToken sets up an initial peer URLsMap and cluster token for bootstrap or discovery.
+func (cfg *Config) PeerURLsMapAndToken(which string) (urlsmap types.URLsMap, token string, err error) {
+	switch {
+	case cfg.Durl != "":
+		urlsmap = types.URLsMap{}
+		// If using discovery, generate a temporary cluster based on
+		// self's advertised peer URLs
+		urlsmap[cfg.Name] = cfg.APUrls
+		token = cfg.Durl
+	case cfg.DNSCluster != "":
+		var clusterStr string
+		clusterStr, token, err = discovery.SRVGetCluster(cfg.Name, cfg.DNSCluster, cfg.InitialClusterToken, cfg.APUrls)
+		if err != nil {
+			return nil, "", err
+		}
+		urlsmap, err = types.NewURLsMap(clusterStr)
+		// only etcd member must belong to the discovered cluster.
+		// proxy does not need to belong to the discovered cluster.
+		if which == "etcd" {
+			if _, ok := urlsmap[cfg.Name]; !ok {
+				return nil, "", fmt.Errorf("cannot find local etcd member %q in SRV records", cfg.Name)
+			}
+		}
+	default:
+		// We're statically configured, and cluster has appropriately been set.
+		urlsmap, err = types.NewURLsMap(cfg.InitialCluster)
+		token = cfg.InitialClusterToken
+	}
+	return urlsmap, token, err
+}
+
+func (cfg Config) InitialClusterFromName(name string) (ret string) {
+	if len(cfg.APUrls) == 0 {
+		return ""
+	}
+	n := name
+	if name == "" {
+		n = DefaultName
+	}
+	for i := range cfg.APUrls {
+		ret = ret + "," + n + "=" + cfg.APUrls[i].String()
+	}
+	return ret[1:]
+}
+
+func (cfg Config) IsNewCluster() bool { return cfg.ClusterState == ClusterStateFlagNew }
+func (cfg Config) ElectionTicks() int { return int(cfg.ElectionMs / cfg.TickMs) }