Reinstate "Fix Basic RPC Tunnel with Tramp, and Enhance Tunnelling fo…

…r Multihop Usage (#357)"

This reverts commit 24aa81b.
This was initially reverted due to #358, but it appears that this
commit was actually not the source of the problem. Reinstating this
commit unless problems start to appear.

anaconda-mode.el

@@ -69,6 +69,11 @@
   "If the value is not nil, use posframe to show eldoc."
   :type 'boolean)
 
+(defcustom anaconda-mode-tunnel-setup-sleep 2
+  "Time in seconds `anaconda-mode' waits after tunnel creation before first RPC call."
+  :group 'anaconda-mode
+  :type 'integer)
+
 
 ;;; Compatibility
 
@@ -403,6 +408,25 @@ be bound."
     (process-put anaconda-mode-process 'remote-host (pythonic-remote-host))
     (process-put anaconda-mode-process 'remote-port (pythonic-remote-port))))
 
+(defun anaconda-jump-proxy-string ()
+  "Create -J option string for SSH tunnel."
+  (let ((dfn
+         (tramp-dissect-file-name (pythonic-aliased-path default-directory))))
+    (when (tramp-file-name-hop dfn)
+      (let ((hop-list (split-string (tramp-file-name-hop dfn) "|"))
+            (result "-J "))
+        (delete "" hop-list) ;; remove empty string after final pipe
+        (dolist (elt hop-list result)
+          ;; tramp-dissect-file-name expects a filename so give it dummy.file
+          (let ((ts (tramp-dissect-file-name (concat "/" elt ":/dummy.file"))))
+            (setq result (concat result
+                                 (format "%s@%s:%s,"
+                                         (tramp-file-name-user ts)
+                                         (tramp-file-name-host ts)
+                                         (or (tramp-file-name-port-or-default ts) 22))))))
+        ;; Remove final comma
+        (substring result 0 -1)))))
+
 (defun anaconda-mode-bootstrap-filter (process output &optional callback)
   "Set `anaconda-mode-port' from PROCESS OUTPUT.
 Connect to the `anaconda-mode' server.  CALLBACK function will be
@@ -436,14 +460,25 @@ called when `anaconda-mode-port' will be bound."
                                     (format "TCP4:%s:%d" container-ip (anaconda-mode-port))))
                (set-process-query-on-exit-flag anaconda-mode-socat-process nil)))
             ((pythonic-remote-ssh-p)
-             (setq anaconda-mode-ssh-process
-                   (start-process anaconda-mode-ssh-process-name
-                                  anaconda-mode-ssh-process-buffer
-                                  "ssh" "-nNT"
-                                  (format "%s@%s" (pythonic-remote-user) (pythonic-remote-host))
-                                  "-p" (number-to-string (pythonic-remote-port))
-                                  "-L" (format "%s:%s:%s" (anaconda-mode-port) (pythonic-remote-host) (anaconda-mode-port))))
-             (set-process-query-on-exit-flag anaconda-mode-ssh-process nil)))
+             (let ((jump (anaconda-jump-proxy-string)))
+               (message (format "Anaconda Jump Proxy: %s" jump))
+               (setq anaconda-mode-ssh-process
+                     (if jump
+                         (start-process anaconda-mode-ssh-process-name
+                                        anaconda-mode-ssh-process-buffer
+                                        "ssh" jump "-nNT"
+                                        "-L" (format "%s:localhost:%s" (anaconda-mode-port) (anaconda-mode-port))
+                                        (format "%s@%s" (pythonic-remote-user) (pythonic-remote-host))
+                                        "-p" (number-to-string (or (pythonic-remote-port) 22)))
+                       (start-process anaconda-mode-ssh-process-name
+                                      anaconda-mode-ssh-process-buffer
+                                      "ssh" "-nNT"
+                                      "-L" (format "%s:localhost:%s" (anaconda-mode-port) (anaconda-mode-port))
+                                      (format "%s@%s" (pythonic-remote-user) (pythonic-remote-host))
+                                      "-p" (number-to-string (or (pythonic-remote-port) 22)))))
+               ;; prevent race condition between tunnel setup and first use
+               (sleep-for anaconda-mode-tunnel-setup-sleep)
+               (set-process-query-on-exit-flag anaconda-mode-ssh-process nil))))
       (when callback
         (funcall callback)))))
 
@@ -464,7 +499,7 @@ number position, column number position and file path."
   (let ((url-request-method "POST")
         (url-request-data (anaconda-mode-jsonrpc-request command)))
     (url-retrieve
-     (format "http://%s:%s" (anaconda-mode-host) (anaconda-mode-port))
+     (format "http://localhost:%s" (anaconda-mode-port))
      (anaconda-mode-create-response-handler callback)
      nil
      t)))