Allow multiple arguments for exec commands

If you can have an alias like:

```
aliases:
  rails: app exec -p rails
```

Then `kamal rails db:migrate:status` will execute
`kamal app exec -p rails db:migrate:status`.

So this works, we'll allow multiple arguments `app exec` and
`server exec` to accept multiple arguments.

The arguments are combined by simply joining them with a space. This
means that these are equivalent:

```
kamal app exec -p rails db:migrate:status
kamal app exec -p "rails db:migrate:status"
```

If you want to pass an argument with spaces, you'll need to quote it:

```
kamal app exec -p "git commit -am \"My comment\""
kamal app exec -p git commit -am "\"My comment\""
```

lib/kamal/cli/app.rb

@@ -71,11 +71,12 @@ class Kamal::Cli::App < Kamal::Cli::Base
     end
   end
 
-  desc "exec [CMD]", "Execute a custom command on servers within the app container (use --help to show options)"
+  desc "exec [CMD...]", "Execute a custom command on servers within the app container (use --help to show options)"
   option :interactive, aliases: "-i", type: :boolean, default: false, desc: "Execute command over ssh for an interactive shell (use for console/bash)"
   option :reuse, type: :boolean, default: false, desc: "Reuse currently running container instead of starting a new one"
   option :env, aliases: "-e", type: :hash, desc: "Set environment variables for the command"
-  def exec(cmd)
+  def exec(*cmd)
+    cmd = Kamal::Utils.join_commands(cmd)
     env = options[:env]
     case
     when options[:interactive] && options[:reuse]

lib/kamal/cli/server.rb

@@ -1,7 +1,8 @@
 class Kamal::Cli::Server < Kamal::Cli::Base
   desc "exec", "Run a custom command on the server (use --help to show options)"
   option :interactive, type: :boolean, aliases: "-i", default: false, desc: "Run the command interactively (use for console/bash)"
-  def exec(cmd)
+  def exec(*cmd)
+    cmd = Kamal::Utils.join_commands(cmd)
     hosts = KAMAL.hosts | KAMAL.accessory_hosts
 
     case

lib/kamal/utils.rb

@@ -77,4 +77,8 @@ module Kamal::Utils
   def stable_sort!(elements, &block)
     elements.sort_by!.with_index { |element, index| [ block.call(element), index ] }
   end
+
+  def join_commands(commands)
+    commands.map(&:strip).join(" ")
+  end
 end

test/cli/app_test.rb

@@ -247,6 +247,12 @@ class CliAppTest < CliTestCase
     end
   end
 
+  test "exec separate arguments" do
+    run_command("exec", "ruby", " -v").tap do |output|
+      assert_match "docker run --rm --env-file .kamal/env/roles/app-web.env dhh/app:latest ruby -v", output
+    end
+  end
+
   test "exec with reuse" do
     run_command("exec", "--reuse", "ruby -v").tap do |output|
       assert_match "sh -c 'docker ps --latest --format '\\''{{.Names}}'\\'' --filter label=service=app --filter label=role=web --filter status=running --filter status=restarting --filter ancestor=$(docker image ls --filter reference=dhh/app:latest --format '\\''{{.ID}}'\\'') ; docker ps --latest --format '\\''{{.Names}}'\\'' --filter label=service=app --filter label=role=web --filter status=running --filter status=restarting' | head -1 | while read line; do echo ${line#app-web-}; done", output # Get current version

test/cli/main_test.rb

@@ -566,6 +566,13 @@ class CliMainTest < CliTestCase
     end
   end
 
+  test "append to command with an alias" do
+    run_command("rails", "db:migrate:status", config_file: "deploy_with_aliases").tap do |output|
+      assert_match "docker exec app-console-999 rails db:migrate:status on 1.1.1.5", output
+      assert_match "App Host: 1.1.1.5", output
+    end
+  end
+
   private
     def run_command(*command, config_file: "deploy_simple")
       with_argv([ *command, "-c", "test/fixtures/#{config_file}.yml" ]) do

test/cli/server_test.rb

@@ -15,6 +15,20 @@ class CliServerTest < CliTestCase
     end
   end
 
+  test "running a command with exec multiple arguments" do
+    SSHKit::Backend::Abstract.any_instance.stubs(:capture)
+      .with("date -j", verbosity: 1)
+      .returns("Today")
+
+    hosts = "1.1.1.1".."1.1.1.4"
+    run_command("exec", "date", "-j").tap do |output|
+      hosts.map do |host|
+        assert_match "Running 'date -j' on #{hosts.to_a.join(', ')}...", output
+        assert_match "App Host: #{host}\nToday", output
+      end
+    end
+  end
+
   test "bootstrap already installed" do
     stub_setup
     SSHKit::Backend::Abstract.any_instance.expects(:execute).with(:docker, "-v", raise_on_non_zero_exit: false).returns(true).at_least_once

test/fixtures/deploy_with_aliases.yml

@@ -18,3 +18,4 @@ aliases:
   info: details
   console: app exec --reuse -p -r console "bin/console"
   exec: app exec --reuse -p -r console
+  rails: app exec --reuse -p -r console rails

test/integration/docker/deployer/app_with_roles/config/deploy.yml

@@ -40,3 +40,4 @@ readiness_delay: 0
 aliases:
   whome: version
   worker_hostname: app exec -r workers -q --reuse hostname
+  uname: server exec -q -p uname

test/integration/main_test.rb

@@ -93,6 +93,9 @@ class MainTest < IntegrationTest
 
     output = kamal :worker_hostname, capture: true
     assert_match /App Host: vm3\nvm3-[0-9a-f]{12}$/, output
+
+    output = kamal :uname, "-o", capture: true
+    assert_match "App Host: vm1\nGNU/Linux", output
   end
 
   test "setup and remove" do