Minor debugging improvements

- Make LocalProcess.bind_port an Int so it doesn't print in hex.
- Use @error when launching workers so we can show the full backtrace if it
  fails.

Author: JamesWrigley

src/cluster.jl

@@ -214,7 +214,7 @@ end
 mutable struct LocalProcess
     id::Int
     bind_addr::String
-    bind_port::UInt16
+    bind_port::Int
     cookie::String
     LocalProcess() = new(1)
 end
@@ -258,8 +258,8 @@ function start_worker(out::IO, cookie::AbstractString=readline(stdin); close_std
     interface = IPv4(LPROC.bind_addr)
     if LPROC.bind_port == 0
         port_hint = 9000 + (getpid() % 1000)
-        (port, sock) = listenany(interface, UInt16(port_hint))
-        LPROC.bind_port = port
+        (port, sock) = listenany(interface, port_hint)
+        LPROC.bind_port = Int(port)
     else
         sock = listen(interface, LPROC.bind_port)
     end
@@ -268,7 +268,7 @@ function start_worker(out::IO, cookie::AbstractString=readline(stdin); close_std
         process_messages(client, client, true)
     end)
     print(out, "julia_worker:")  # print header
-    print(out, "$(string(LPROC.bind_port))#") # print port
+    print(out, "$(LPROC.bind_port)#") # print port
     print(out, LPROC.bind_addr)
     print(out, '\n')
     flush(out)
@@ -1339,7 +1339,7 @@ function init_bind_addr()
 
     global LPROC
     LPROC.bind_addr = bind_addr
-    LPROC.bind_port = UInt16(bind_port)
+    LPROC.bind_port = bind_port
 end
 
 using Random: randstring

src/managers.jl

@@ -186,7 +186,7 @@ function launch(manager::SSHManager, params::Dict, launched::Array, launch_ntfy:
             @async try
                 launch_on_machine(manager, $machine, $cnt, params, launched, launch_ntfy)
             catch e
-                print(stderr, "exception launching on machine $(machine) : $(e)\n")
+                @error "Exception launching on machine $(machine)" exception=(e, catch_backtrace())
             end
         end
     end