removed etcd mandatory dependency (#195)

pkg/c2s/resource_manager.go

@@ -19,7 +19,6 @@ import (
 	"fmt"
 	"strings"
 	"sync"
-	"time"
 
 	kitlog "github.com/go-kit/log"
 
@@ -38,8 +37,6 @@ const (
 	resourceKeyPrefix = "r://"
 )
 
-const clearActiveKeyTimeout = time.Minute
-
 // ResourceManager type is in charge of keeping track of all cluster resources.
 type ResourceManager struct {
 	kv        kv.KV

pkg/cluster/etcd/etcd.go

@@ -18,7 +18,7 @@ import "time"
 
 // Config contains etcd configuration parameters.
 type Config struct {
-	Endpoints            []string      `fig:"endpoints" default:"[http://localhost:2379]"`
+	Endpoints            []string      `fig:"endpoints"`
 	DialTimeout          time.Duration `fig:"dial_timeout" default:"20s"`
 	DialKeepAliveTime    time.Duration `fig:"dial_keep_alive_time" default:"30s"`
 	DialKeepAliveTimeout time.Duration `fig:"dial_keep_alive_timeout" default:"10s"`

pkg/cluster/kv/nop_kv.go

@@ -0,0 +1,41 @@
+// Copyright 2021 The jackal 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 kv
+
+import "context"
+
+// NewNopKV returns a KV that doesn't do anything.
+func NewNopKV() KV { return &nopKV{} }
+
+type nopKV struct{}
+
+func (k *nopKV) Put(_ context.Context, _ string, _ string) error { return nil }
+func (k *nopKV) Get(_ context.Context, _ string) ([]byte, error) { return nil, nil }
+
+func (k *nopKV) GetPrefix(_ context.Context, _ string) (map[string][]byte, error) {
+	return nil, nil
+}
+
+func (k *nopKV) Del(_ context.Context, _ string) error { return nil }
+
+func (k *nopKV) Watch(_ context.Context, _ string, _ bool) <-chan WatchResp {
+	// return an already closed channel
+	retCh := make(chan WatchResp)
+	close(retCh)
+	return retCh
+}
+
+func (k *nopKV) Start(_ context.Context) error { return nil }
+func (k *nopKV) Stop(_ context.Context) error  { return nil }

pkg/cluster/locker/locker.go

@@ -30,6 +30,6 @@ type Locker interface {
 
 // Lock defines distributed lock object.
 type Lock interface {
-	// Releases releases a previously acquired lock.
+	// Release releases a previously acquired lock.
 	Release(ctx context.Context) error
 }

pkg/cluster/locker/nop_locker.go

@@ -0,0 +1,33 @@
+// Copyright 2021 The jackal 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 locker
+
+import "context"
+
+// NewNopLocker returns a Locker that doesn't do anything.
+func NewNopLocker() Locker { return &nopLocker{} }
+
+type nopLocker struct{}
+
+func (l *nopLocker) AcquireLock(_ context.Context, _ string) (Lock, error) {
+	return &nopLock{}, nil
+}
+
+func (l *nopLocker) Start(_ context.Context) error { return nil }
+func (l *nopLocker) Stop(_ context.Context) error  { return nil }
+
+type nopLock struct{}
+
+func (l *nopLock) Release(_ context.Context) error { return nil }

pkg/jackal/jackal.go

@@ -138,6 +138,8 @@ func New(output io.Writer, args []string) *Jackal {
 		output:     output,
 		args:       args,
 		waitStopCh: make(chan os.Signal, 1),
+		locker:     locker.NewNopLocker(),
+		kv:         kv.NewNopKV(),
 	}
 }
 
@@ -212,11 +214,13 @@ func (j *Jackal) Run() error {
 	j.hk = hook.NewHooks()
 
 	// init etcd
-	if err := j.checkEtcdHealth(cfg.Cluster.Etcd.Endpoints); err != nil {
-		return err
+	if len(cfg.Cluster.Etcd.Endpoints) > 0 {
+		if err := j.checkEtcdHealth(cfg.Cluster.Etcd.Endpoints); err != nil {
+			return err
+		}
+		j.initLocker(cfg.Cluster.Etcd)
+		j.initKVStore(cfg.Cluster.Etcd)
 	}
-	j.initLocker(cfg.Cluster.Etcd)
-	j.initKVStore(cfg.Cluster.Etcd)
 
 	// init cluster connection manager
 	j.initClusterConnManager()