Add access format support for Elasticsearch notification target (#4006)

This change adds `access` format support for notifications to a
Elasticsearch server, and it refactors `namespace` format support.

In the case of `access` format, for each event in Minio, a JSON
document is inserted into Elasticsearch with its timestamp set to the
event's timestamp, and with the ID generated automatically by
elasticsearch. No events are modified or deleted in this mode.

In the case of `namespace` format, for each event in Minio, a JSON
document is keyed together by the bucket and object name is updated in
Elasticsearch. In the case of an object being created or over-written
in Minio, a new document or an existing document is inserted into the
Elasticsearch index. If an object is deleted in Minio, the
corresponding document is deleted from the Elasticsearch index.

Additionally, this change upgrades Elasticsearch support to the 5.x
series. This is a breaking change, and users of previous elasticsearch
versions should upgrade.

Also updates documentation on Elasticsearch notification target usage
and has a link to an elasticsearch upgrade guide.

This is the last patch that finally resolves #3928.

cmd/notify-mysql.go

@@ -90,14 +90,11 @@ VALUES (?, ?);`
 	tableExistsMySQL = `SELECT 1 FROM %s;`
 )
 
-func makeMySQLError(msg string, a ...interface{}) error {
-	s := fmt.Sprintf(msg, a...)
-	return fmt.Errorf("MySQL Notifier Error: %s", s)
-}
-
 var (
-	myNFormatError = makeMySQLError(`"format" value is invalid - it must be one of "%s" or "%s".`, formatNamespace, formatAccess)
-	myNTableError  = makeMySQLError("Table was not specified in the configuration.")
+	mysqlErrFunc = newNotificationErrorFactory("MySQL")
+
+	errMysqlFormat = mysqlErrFunc(`"format" value is invalid - it must be one of "%s" or "%s".`, formatNamespace, formatAccess)
+	errMysqlTable  = mysqlErrFunc("Table was not specified in the configuration.")
 )
 
 type mySQLNotify struct {
@@ -127,7 +124,7 @@ func (m *mySQLNotify) Validate() error {
 		return nil
 	}
 	if m.Format != formatNamespace && m.Format != formatAccess {
-		return myNFormatError
+		return errMysqlFormat
 	}
 	if m.DsnString == "" {
 		if _, err := checkURL(m.Host); err != nil {
@@ -135,7 +132,7 @@ func (m *mySQLNotify) Validate() error {
 		}
 	}
 	if m.Table == "" {
-		return myNTableError
+		return errMysqlTable
 	}
 	return nil
 }
@@ -169,7 +166,7 @@ func dialMySQL(msql mySQLNotify) (mySQLConn, error) {
 
 	db, err := sql.Open("mysql", dsnStr)
 	if err != nil {
-		return mySQLConn{}, makeMySQLError(
+		return mySQLConn{}, mysqlErrFunc(
 			"Connection opening failure (dsnStr=%s): %v",
 			dsnStr, err)
 	}
@@ -177,7 +174,7 @@ func dialMySQL(msql mySQLNotify) (mySQLConn, error) {
 	// ping to check that server is actually reachable.
 	err = db.Ping()
 	if err != nil {
-		return mySQLConn{}, makeMySQLError(
+		return mySQLConn{}, mysqlErrFunc(
 			"Ping to server failed with: %v", err)
 	}
 
@@ -193,7 +190,7 @@ func dialMySQL(msql mySQLNotify) (mySQLConn, error) {
 		_, errCreate := db.Exec(fmt.Sprintf(createStmt, msql.Table))
 		if errCreate != nil {
 			// failed to create the table. error out.
-			return mySQLConn{}, makeMySQLError(
+			return mySQLConn{}, mysqlErrFunc(
 				"'Select' failed with %v, then 'Create Table' failed with %v",
 				err, errCreate,
 			)
@@ -209,21 +206,21 @@ func dialMySQL(msql mySQLNotify) (mySQLConn, error) {
 			msql.Table))
 		if err != nil {
 			return mySQLConn{},
-				makeMySQLError("create UPSERT prepared statement failed with: %v", err)
+				mysqlErrFunc("create UPSERT prepared statement failed with: %v", err)
 		}
 		// delete statement
 		stmts["deleteRow"], err = db.Prepare(fmt.Sprintf(deleteRowForNSMySQL,
 			msql.Table))
 		if err != nil {
 			return mySQLConn{},
-				makeMySQLError("create DELETE prepared statement failed with: %v", err)
+				mysqlErrFunc("create DELETE prepared statement failed with: %v", err)
 		}
 	case formatAccess:
 		// insert statement
 		stmts["insertRow"], err = db.Prepare(fmt.Sprintf(insertRowForAccessMySQL,
 			msql.Table))
 		if err != nil {
-			return mySQLConn{}, makeMySQLError(
+			return mySQLConn{}, mysqlErrFunc(
 				"create INSERT prepared statement failed with: %v", err)
 		}
 
@@ -274,7 +271,7 @@ func (myC mySQLConn) Fire(entry *logrus.Entry) error {
 			"Records": d,
 		})
 		if err != nil {
-			return nil, makeMySQLError(
+			return nil, mysqlErrFunc(
 				"Unable to encode event %v to JSON: %v", d, err)
 		}
 		return value, nil
@@ -287,7 +284,7 @@ func (myC mySQLConn) Fire(entry *logrus.Entry) error {
 			// delete row from the table
 			_, err := myC.preparedStmts["deleteRow"].Exec(entry.Data["Key"])
 			if err != nil {
-				return makeMySQLError(
+				return mysqlErrFunc(
 					"Error deleting event with key = %v - got mysql error - %v",
 					entry.Data["Key"], err,
 				)
@@ -301,7 +298,7 @@ func (myC mySQLConn) Fire(entry *logrus.Entry) error {
 			// upsert row into the table
 			_, err = myC.preparedStmts["upsertRow"].Exec(entry.Data["Key"], value)
 			if err != nil {
-				return makeMySQLError(
+				return mysqlErrFunc(
 					"Unable to upsert event with Key=%v and Value=%v - got mysql error - %v",
 					entry.Data["Key"], entry.Data["Records"], err,
 				)
@@ -312,11 +309,11 @@ func (myC mySQLConn) Fire(entry *logrus.Entry) error {
 		// records.
 		events, ok := entry.Data["Records"].([]NotificationEvent)
 		if !ok {
-			return makeMySQLError("unable to extract event time due to conversion error of entry.Data[\"Records\"]=%v", entry.Data["Records"])
+			return mysqlErrFunc("unable to extract event time due to conversion error of entry.Data[\"Records\"]=%v", entry.Data["Records"])
 		}
 		eventTime, err := time.Parse(timeFormatAMZ, events[0].EventTime)
 		if err != nil {
-			return makeMySQLError("unable to parse event time \"%s\": %v",
+			return mysqlErrFunc("unable to parse event time \"%s\": %v",
 				events[0].EventTime, err)
 		}
 
@@ -327,7 +324,7 @@ func (myC mySQLConn) Fire(entry *logrus.Entry) error {
 
 		_, err = myC.preparedStmts["insertRow"].Exec(eventTime, value)
 		if err != nil {
-			return makeMySQLError("Unable to insert event with value=%v: %v",
+			return mysqlErrFunc("Unable to insert event with value=%v: %v",
 				value, err)
 		}
 	}