allow customization of ssh fwd port (fixes mschubert#296)

Author: mschubert

R/qsys_ssh.r

@@ -23,7 +23,7 @@ SSH = R6::R6Class("SSH",
             # set forward and run ssh.r (send port, master)
             opts = private$fill_options(ssh_log=ssh_log, ssh_host=ssh_host)
             ssh_cmd = fill_template(private$template, opts,
-                required=c("local_port", "remote_port", "ssh_host"))
+                required=c("local_port", "ssh.hpc_fwd_port", "ssh_host"))
 
             # wait for ssh to connect
             message(sprintf("Connecting to %s via SSH ...", sQuote(ssh_host)))
@@ -52,11 +52,10 @@ SSH = R6::R6Class("SSH",
         ssh_proxy_running = TRUE,
 
         fill_options = function(...) {
-            values = utils::modifyList(private$defaults, list(...))
-            #TODO: let user define ports in private$defaults here and respect them
-            values$local_port = sub(".*:", "", private$addr)
-            values$remote_port = sample(50000:55000, 1)
-            values
+            args = list(...)
+            args$local_port = sub(".*:", "", private$addr)
+            args$ssh.hpc_fwd_port = getOption("clustermq.ssh.hpc_fwd_port", sample(50000:55000, 1))
+            utils::modifyList(private$defaults, args)
         },
 
         finalize = function(quiet = self$workers_running == 0) {

inst/SSH.tmpl

@@ -1,6 +1,6 @@
 ssh -o "ExitOnForwardFailure yes" -f
-    -R {{ remote_port }}:127.0.0.1:{{ local_port }}
+    -R {{ ssh.hpc_fwd_port }}:127.0.0.1:{{ local_port }}
     {{ ssh_host }}
     "R --no-save --no-restore -e
-        'clustermq:::ssh_proxy({{ remote_port }})'
+        'clustermq:::ssh_proxy({{ ssh.hpc_fwd_port }})'
         > {{ ssh_log | /dev/null }} 2>&1"

vignettes/userguide.Rmd

@@ -293,6 +293,9 @@ time after you restart R.
       (e.g. `"~/cmq_ssh.log"`); helpful for debugging purposes
 * `clustermq.ssh.timeout` - The amount of time to wait (in seconds) for a SSH
       start-up connection before timing out (default is `10` seconds)
+* `clustermq.ssh.hpc_fwd_port` - Port that will be opened for SSH reverse
+      tunneling between the workers on the HPC and a local session
+      (default: one integer in the range of 50-55k)
 * `clustermq.worker.timeout` - The amount of time to wait (in seconds) for
       master-worker communication before timing out (default is to wait
       indefinitely)