Pass all JULIA_* environment variables by default in the SSHManager

It's otherwise very annoying and error-prone to set these with every call to
`addprocs()`.

Author: JamesWrigley

docs/src/_changelog.md

@@ -20,3 +20,5 @@ This documents notable changes in DistributedNext.jl. The format is based on
   the project of a remote worker ([#2]).
 - Workers will now attempt to pick the fastest available interface to
   communicate over ([#9]).
+- The `SSHManager` now passes all `JULIA_*` environment variables by default to
+  the workers, instead of only `JULIA_WORKER_TIMEOUT` ([#9]).

src/managers.jl

@@ -138,9 +138,8 @@ addprocs([
 
 * `env`: provide an array of string pairs such as
   `env=["JULIA_DEPOT_PATH"=>"/depot"]` to request that environment variables
-  are set on the remote machine. By default only the environment variable
-  `JULIA_WORKER_TIMEOUT` is passed automatically from the local to the remote
-  environment.
+  are set on the remote machine. By default all `JULIA_*` environment variables
+  are passed automatically from the local to the remote environment.
 
 * `cmdline_cookie`: pass the authentication cookie via the `--worker` commandline
    option. The (more secure) default behaviour of passing the cookie via ssh stdio
@@ -294,8 +293,9 @@ function launch_on_machine(manager::SSHManager, machine::AbstractString, cnt, pa
     # Build up the ssh command
 
     # pass on some environment variables by default
-    for var in ["JULIA_WORKER_TIMEOUT"]
-        if !haskey(env, var) && haskey(ENV, var)
+    julia_vars = filter(startswith("JULIA_"), keys(ENV))
+    for var in julia_vars
+        if !haskey(env, var)
             env[var] = ENV[var]
         end
     end

test/sshmanager.jl

@@ -71,6 +71,13 @@ end
         test_n_remove_pids(new_pids)
         @test :ok == timedwait(()->!issocket(controlpath), 10.0; pollint=0.5)
 
+        print("\nTest SSH addprocs() passing environment variables\n")
+        withenv("JULIA_FOO" => "foo") do
+            new_pids = addprocs_with_testenv(["localhost"]; sshflags)
+            @test remotecall_fetch(() -> ENV["JULIA_FOO"], only(new_pids)) == "foo"
+            test_n_remove_pids(new_pids)
+        end
+
         print("\nAll supported formats for hostname\n")
         h1 = "localhost"
         user = ENV["USER"]