recan session during node stage

Signed-off-by: Travis Glenn Hansen <travisghansen@yahoo.com>

README.md

@@ -40,6 +40,8 @@ Predominantly 3 things are needed:
 ## Guides
 
 - https://jonathangazeley.com/2021/01/05/using-truenas-to-provide-persistent-storage-for-kubernetes/
+- https://gist.github.com/admun/4372899f20421a947b7544e5fc9f9117 (migrating
+  from `nfs-client-provisioner` to `democratic-csi`)
 
 ## Node Prep
 

src/driver/index.js

@@ -343,6 +343,7 @@ class CsiBaseDriver {
           // put these options in place to force targets managed by csi to be explicitly attached (in the case of unclearn shutdown etc)
           let nodeDB = {
             "node.startup": "manual",
+            //"node.session.scan": "manual",
           };
           const nodeDBKeyPrefix = "node-db.";
           for (const key in normalizedSecrets) {
@@ -359,6 +360,15 @@ class CsiBaseDriver {
           // login
           await iscsi.iscsiadm.login(volume_context.iqn, portal);
 
+          // get associated session
+          let session = await iscsi.iscsiadm.getSession(
+            volume_context.iqn,
+            portal
+          );
+
+          // rescan in scenarios when login previously occurred but volumes never appeared
+          await iscsi.iscsiadm.rescanSession(session);
+
           // find device name
           device = `/dev/disk/by-path/ip-${portal}-iscsi-${volume_context.iqn}-lun-${volume_context.lun}`;
           let deviceByPath = device;

src/utils/iscsi.js

@@ -1,4 +1,5 @@
 const cp = require("child_process");
+const { setegid } = require("process");
 
 function getIscsiValue(value) {
   if (value == "<empty>") return null;
@@ -147,6 +148,27 @@ class ISCSI {
         await iscsi.exec(options.paths.iscsiadm, args);
       },
 
+      /**
+       * get session object by iqn/portal
+       */
+      async getSession(tgtIQN, portal) {
+        const sessions = await iscsi.iscsiadm.getSessions();
+
+        let session = false;
+        sessions.every((i_session) => {
+          if (
+            `${i_session.iqn}:${i_session.target}` == tgtIQN &&
+            portal == i_session.portal
+          ) {
+            session = i_session;
+            return false;
+          }
+          return true;
+        });
+
+        return session;
+      },
+
       /**
        * iscsiadm -m session
        */
@@ -178,7 +200,7 @@ class ISCSI {
           fields = entry.split(" ");
           sessions.push({
             protocol: entry.split(":")[0],
-            id: fields[1].replace("[", "").replace("]", ""),
+            id: Number(fields[1].replace("[", "").replace("]", "")),
             portal: fields[2].split(",")[0],
             target_portal_group_tag: fields[2].split(",")[1],
             iqn: fields[3].split(":")[0],
@@ -438,6 +460,36 @@ class ISCSI {
 
         return true;
       },
+
+      /**
+       * iscsiadm -m session -r SID --rescan
+       *
+       * @param {*} session
+       */
+      async rescanSession(session) {
+        let sid;
+        if (typeof session === "object") {
+          sid = session.id;
+        } else {
+          sid = session;
+        }
+
+        // make sure session is a valid number
+        if (session !== 0 && session > 0) {
+          throw new Error("cannot scan empty session id");
+        }
+
+        let args = [];
+        args = args.concat(["-m", "session", "-r", sid, "--rescan"]);
+
+        try {
+          await iscsi.exec(options.paths.iscsiadm, args);
+        } catch (err) {
+          throw err;
+        }
+
+        return true;
+      },
     };
   }