add code to discover the target

This commit add the feature to discover the target based on the flag Discovery,
which can be set while initializing iscsi.Connector structure. It also adds
another flag CHAPDiscovery to proceed to discover the target without secrets.

Signed-off-by: Utkarsh Mani Tripathi <[email protected]>

Author: Utkarsh Mani Tripathi

iscsi/iscsi.go

@@ -46,6 +46,8 @@ type Connector struct {
 	Multipath        bool     `json:"multipath"`
 	RetryCount       int32    `json:"retry_count"`
 	CheckInterval    int32    `json:"check_interval"`
+	Discovery        bool     `json:"discovery"`
+	CHAPDiscovery    bool     `json:"chap_discovery"`
 }
 
 func init() {
@@ -221,7 +223,7 @@ func getMultipathDisk(path string) (string, error) {
 
 // Connect attempts to connect a volume to this node using the provided Connector info
 func Connect(c Connector) (string, error) {
-
+	var lastErr error
 	if c.RetryCount == 0 {
 		c.RetryCount = 10
 	}
@@ -249,6 +251,11 @@ func Connect(c Connector) (string, error) {
 	for _, p := range c.TargetPortals {
 		debug.Printf("process portal: %s\n", p)
 		baseArgs := []string{"-m", "node", "-T", c.TargetIqn, "-p", p}
+		// Rescan sessions to discover newly mapped LUNs. Do not specify the interface when rescanning
+		// to avoid establishing additional sessions to the same target.
+		if _, err := iscsiCmd(append(baseArgs, []string{"-R"}...)...); err != nil {
+			debug.Printf("failed to rescan session, err: %v", err)
+		}
 
 		// create our devicePath that we'll be looking for based on the transport being used
 		if c.Port != "" {
@@ -270,31 +277,45 @@ func Connect(c Connector) (string, error) {
 			}
 		}
 
-		// create db entry
-		args := append(baseArgs, []string{"-I", iFace, "-o", "new"}...)
-		debug.Printf("create the new record: %s\n", args)
+		if c.Discovery {
+			// build discoverydb and discover iscsi target
+			if err := Discovery(p, iFace, c.DiscoverySecrets, c.CHAPDiscovery); err != nil {
+				debug.Printf("Error in discovery of the target: %s\n", err.Error())
+				lastErr = err
+				continue
+			}
+		}
+
 		// Make sure we don't log the secrets
-		err := CreateDBEntry(c.TargetIqn, p, iFace, c.DiscoverySecrets, c.SessionSecrets)
+		err := CreateDBEntry(c.TargetIqn, p, iFace, c.DiscoverySecrets, c.SessionSecrets, c.CHAPDiscovery)
 		if err != nil {
 			debug.Printf("Error creating db entry: %s\n", err.Error())
 			continue
 		}
+
 		// perform the login
 		err = Login(c.TargetIqn, p)
 		if err != nil {
-			return "", err
+			debug.Printf("failed to login, err: %v", err)
+			lastErr = err
+			continue
 		}
 		retries := int(c.RetryCount / c.CheckInterval)
 		if exists, err := waitForPathToExist(&devicePath, retries, int(c.CheckInterval), iscsiTransport); exists {
 			devicePaths = append(devicePaths, devicePath)
 			continue
 		} else if err != nil {
-			return "", err
-		}
-		if len(devicePaths) < 1 {
-			return "", fmt.Errorf("failed to find device path: %s", devicePath)
+			lastErr = fmt.Errorf("Couldn't attach disk, err: %v", err)
 		}
+	}
+
+	if len(devicePaths) < 1 {
+		iscsiCmd([]string{"-m", "iface", "-I", iFace, "-o", "delete"}...)
+		return "", fmt.Errorf("failed to find device path: %s, last error seen: %v", devicePaths, lastErr)
+	}
 
+	if lastErr != nil {
+		debug.Printf("Last error occured during iscsi init: \n%v", lastErr)
 	}
 
 	for i, path := range devicePaths {

iscsi/iscsiadm.go

@@ -88,13 +88,17 @@ func ShowInterface(iface string) (string, error) {
 }
 
 // CreateDBEntry sets up a node entry for the specified tgt in the nodes iscsi nodes db
-func CreateDBEntry(tgtIQN, portal, iFace string, discoverySecrets, sessionSecrets Secrets) error {
+func CreateDBEntry(tgtIQN, portal, iFace string, discoverySecrets, sessionSecrets Secrets, chapDiscovery bool) error {
 	debug.Println("Begin CreateDBEntry...")
+	if !chapDiscovery {
+		return nil
+	}
 	baseArgs := []string{"-m", "node", "-T", tgtIQN, "-p", portal}
 	_, err := iscsiCmd(append(baseArgs, []string{"-I", iFace, "-o", "new"}...)...)
 	if err != nil {
 		return err
 	}
+
 	if discoverySecrets.SecretsType == "chap" {
 		debug.Printf("Setting CHAP Discovery...")
 		createCHAPEntries(baseArgs, discoverySecrets, true)
@@ -103,25 +107,59 @@ func CreateDBEntry(tgtIQN, portal, iFace string, discoverySecrets, sessionSecret
 	if sessionSecrets.SecretsType == "chap" {
 		debug.Printf("Setting CHAP Session...")
 		createCHAPEntries(baseArgs, sessionSecrets, false)
-
 	}
+
 	return err
 
 }
 
+func updateISCSIDiscoverydb(tp, iface string, discoverySecrets Secrets) error {
+	baseArgs := []string{"-m", "discoverydb", "-t", "sendtargets", "-p", tp, "-I", iface}
+	_, err := iscsiCmd(append(baseArgs, []string{"-o", "update", "-n", "discovery.sendtargets.auth.authmethod", "-v", "CHAP"}...)...)
+	if err != nil {
+		return fmt.Errorf("failed to update discoverydb with CHAP, err: %v", err)
+	}
+
+	return createCHAPEntries(baseArgs, discoverySecrets, true)
+}
+
+// Discovery discover the iscsi target
+func Discovery(tp, iface string, discoverySecrets Secrets, chapDiscovery bool) error {
+	debug.Println("Begin Discovery...")
+	baseArgs := []string{"-m", "discoverydb", "-t", "sendtargets", "-p", tp, "-I", iface}
+	out, err := iscsiCmd(append(baseArgs, []string{"-o", "new"}...)...)
+	if err != nil {
+		return fmt.Errorf("failed to create new entry of target in discoverydb, output: %v, err: %v", string(out), err)
+	}
+
+	if chapDiscovery {
+		if err := updateISCSIDiscoverydb(tp, iface, discoverySecrets); err != nil {
+			return err
+		}
+	}
+
+	_, err = iscsiCmd(append(baseArgs, []string{"--discover"}...)...)
+	if err != nil {
+		//delete the discoverydb record
+		iscsiCmd(append(baseArgs, []string{"-o", "delete"}...)...)
+		return fmt.Errorf("failed to sendtargets to portal %s, err: %v", tp, err)
+	}
+	return nil
+}
+
 func createCHAPEntries(baseArgs []string, secrets Secrets, discovery bool) error {
 	args := []string{}
 	debug.Printf("Begin createCHAPEntries (discovery=%t)...", discovery)
 	if discovery {
 		args = append(baseArgs, []string{"-o", "update",
-			"-n", "node.discovery.auth.authmethod", "-v", "CHAP",
-			"-n", "node.discovery.auth.username", "-v", secrets.UserName,
-			"-n", "node.discovery.auth.password", "-v", secrets.Password}...)
+			"-n", "discovery.sendtargets.auth.authmethod", "-v", "CHAP",
+			"-n", "discovery.sendtargets.auth.username", "-v", secrets.UserName,
+			"-n", "discovery.sendtargets.auth.password", "-v", secrets.Password}...)
 		if secrets.UserNameIn != "" {
-			args = append(args, []string{"-n", "node.discovery.auth.username_in", "-v", secrets.UserNameIn}...)
+			args = append(args, []string{"-n", "discovery.sendtargets.auth.username_in", "-v", secrets.UserNameIn}...)
 		}
-		if secrets.UserNameIn != "" {
-			args = append(args, []string{"-n", "node.discovery.auth.password_in", "-v", secrets.PasswordIn}...)
+		if secrets.PasswordIn != "" {
+			args = append(args, []string{"-n", "discovery.sendtargets.auth.password_in", "-v", secrets.PasswordIn}...)
 		}
 
 	} else {
@@ -133,13 +171,17 @@ func createCHAPEntries(baseArgs []string, secrets Secrets, discovery bool) error
 		if secrets.UserNameIn != "" {
 			args = append(args, []string{"-n", "node.session.auth.username_in", "-v", secrets.UserNameIn}...)
 		}
-		if secrets.UserNameIn != "" {
+		if secrets.PasswordIn != "" {
 			args = append(args, []string{"-n", "node.session.auth.password_in", "-v", secrets.PasswordIn}...)
 		}
 	}
+
 	_, err := iscsiCmd(args...)
-	return err
+	if err != nil {
+		return fmt.Errorf("failed to update discoverydb with CHAP, err: %v", err)
+	}
 
+	return nil
 }
 
 // GetSessions retrieves a list of current iscsi sessions on the node
@@ -151,7 +193,13 @@ func GetSessions() (string, error) {
 
 // Login performs an iscsi login for the specified target
 func Login(tgtIQN, portal string) error {
-	_, err := iscsiCmd([]string{"-m", "node", "-T", tgtIQN, "-p", portal, "-l"}...)
+	baseArgs := []string{"-m", "node", "-T", tgtIQN, "-p", portal}
+	_, err := iscsiCmd(append(baseArgs, []string{"-l"}...)...)
+	if err != nil {
+		//delete the node record from database
+		iscsiCmd(append(baseArgs, []string{"-o", "delete"}...)...)
+		return fmt.Errorf("failed to sendtargets to portal %s, err: %v", portal, err)
+	}
 	return err
 }
 
@@ -173,5 +221,11 @@ func DeleteDBEntry(tgtIQN string) error {
 	args := []string{"-m", "node", "-T", tgtIQN, "-o", "delete"}
 	iscsiCmd(args...)
 	return nil
+}
 
+// DeleteIFace delete the iface
+func DeleteIFace(iface string) error {
+	debug.Println("Begin DeleteIFace...")
+	iscsiCmd([]string{"-m", "iface", "-I", iface, "-o", "delete"}...)
+	return nil
 }