Example of parallel remote tasks

Author: pmeinhardt

examples/parallel.exs

@@ -0,0 +1,53 @@
+defaults = [user: "deploy", password: "deploy", silently_accept_hosts: true]
+
+hosts =
+  [{"127.0.0.1", port: 2222}, {"127.0.0.1", port: 2223}]
+  |> Enum.map(fn {name, options} -> {name, Keyword.merge(defaults, options)} end)
+
+conns = Enum.map(hosts, fn {name, options} ->
+  {:ok, conn} = SSHKit.connect(name, options)
+  conn
+end)
+
+label = fn conn -> Enum.join([conn.host, conn.port], ":") end
+
+tasks =
+  Enum.map(conns, fn conn ->
+    Task.async(fn ->
+      {:ok, chan} = SSHKit.run(conn, "uptime")
+
+      chan
+      |> SSHKit.stream()
+      |> Enum.reduce(nil, fn
+        {:stdout, chan, output}, acc ->
+          IO.write("[#{label.(chan.connection)}] (stdout) #{output}")
+          acc
+
+        {:stderr, chan, output}, acc ->
+          IO.write("[#{label.(chan.connection)}] (stderr) #{output}")
+          acc
+
+        {:exit, _, status}, _ ->
+          status
+
+        _, acc ->
+          acc
+      end)
+    end)
+  end)
+
+okay? = fn status -> status == 0 end
+
+results = Enum.map(tasks, &Task.await/1)
+
+unless Enum.all?(results, okay?) do
+  results
+  |> Enum.with_index()
+  |> Enum.filter(fn {status, _} -> !okay?.(status) end)
+  |> Enum.each(fn {status, index} ->
+    conn = Enum.at(conns, index)
+    IO.puts("[#{label.(conn)}] exited with status #{status}")
+  end)
+end
+
+:ok = Enum.each(conns, &SSHKit.close/1)

examples/stream.exs

@@ -1,5 +1,3 @@
-# TODO: Multiple hosts?
-
 {:ok, conn} = SSHKit.connect("127.0.0.1", port: 2222, user: "deploy", password: "deploy", silently_accept_hosts: true)
 
 {:ok, chan} = SSHKit.run(conn, ~S(echo "Who's there?"; read name; echo "Hello $name"))