// setup continuous replication between all pods in couchdb cluster
// first it will cancel any replication for all pods
// then it will reinit circle continuous replication between all pods
// requirement -> replicas > 1 !!
// @param cluster - CouchdbCluster struct - cluster where setup replication
func (cluster *CouchdbCluster) SetupReplication(databases []string) error {
DebugLog("couchdb_control: setup: _replication: Replication setup for all PODS, dbs to replicate:")
DebugLog(databases)
// check fi all pods are ready and in running state
err := cluster.CheckAllCouchdbPods()
if err != nil {
ErrorLog("couchdb_control: setup_replication: check all pods error")
return err
}
// create couchdb admin credentials
credentials := couch.NewCredentials(cluster.Username, cluster.Password)
// get all pods
podSvcList, err := cluster.GetAllPodServices()
if err != nil {
ErrorLog("couchdb_control: setup_replication: check all pods error")
return err
}
podSvcs := *podSvcList
DebugLog("couchdb_control: setup_replication: interate throught all pod services")
// iterate through all pods
for i := 0; i < len(podSvcs); i++ {
// index of next pod
j := (i + 1) % len(podSvcs)
DebugLog("couchdb_control: setup replication: pod: " + podSvcs[i].Name + "," + podSvcs[i].Spec.ClusterIP)
// primary - replicate FROM
server1 := couch.NewServer("http://"+podSvcs[i].Spec.ClusterIP+":"+COUCHDB_PORT_STRING, credentials)
// check server1
if err := CheckServer(server1, MAX_RETRIES, RETRY_WAIT_TIME); err != nil {
// failed to connect to server after all retries, fail replication
ErrorLog("couchdb_control: setupReplication: failed to connect to server1, pod:" + podSvcs[i].Name)
ErrorLog(err)
return err
}
// secondary - replicate TO
server2 := couch.NewServer("http://"+podSvcs[j].Spec.ClusterIP+":"+COUCHDB_PORT_STRING, credentials)
if err := CheckServer(server2, MAX_RETRIES, RETRY_WAIT_TIME); err != nil {
// failed to connect to server after all retries, fail replication
ErrorLog("couchdb_control: setupReplication: failed to connect to server2, pod:" + podSvcs[j].Name)
ErrorLog(err)
return err
}
// set replication between two pods for all listed databases
for _, db := range databases {
// db1 server1
db1 := server1.Database(db)
db1.Create()
// db1 server2
db2 := server2.Database(db)
db2.Create()
// REPLICATION CHOOSE ONLY ONE
// 1) using _replicate
// 2) using _replicator
// replication struct, use headless service name for replication target
replicator := CouchdbReplicator{Id: "replicate_" + db,
Continuous: true, Source: db1.URL(),
Target: "http://" + cluster.Username + ":" + cluster.Password + "@" + podSvcs[j].Spec.ClusterIP + ":" + COUCHDB_PORT_STRING + "/" + db}
// 1)
// continuous replication , saves to "_replicate"
// limits: anything in _replication is lost when db is restarted
// DELETE old replication, if any found
// cannot by done without saving information or without server restart
// restart server1 and wait until its online, should be fast
//couch.Do(server1.URL()+"/_restart", METHOD_POST, server1.Cred(), nil, nil)
//CheckServer(server1, MAX_RETRIES, RETRY_WAIT_TIME)
// setup replication
//couch.Do(server1.URL()+"/_replicate", METHOD_POST, server1.Cred(), &replicator, nil)
// 2)
// continuous replication via "_replicator"
// this replication survive restarts but fails replicate database "_users"
if db == "_users" {
// there is a bug with _replicator and db _users, we cannot replicate this DB
continue
}
// delete old replication, if any found
// get old replicator record
oldReplicator := CouchdbReplicator{}
couch.Do(server1.URL()+"/_replicator/"+"replicate_"+db, METHOD_GET, server1.Cred(), nil, &oldReplicator)
//DebugLog(oldReplicator.Rev)
// if valid replicator record found, delete it
if oldReplicator.Rev != "" {
server1.Database("_replicator").Delete("replicate_"+db, oldReplicator.Rev)
}
// setup new replication in _replicator db
couch.Do(server1.URL()+"/_replicator", METHOD_POST, server1.Cred(), &replicator, nil)
}
}
//DebugLog("finished replication configuration")
// no errors
return nil
}
func server() *couch.Server {
return couch.NewServer(testHost, testCred)
}