initial implementation and tests for tunnel command

.gitignore

@@ -1 +1,3 @@
 .rubocop-*
+.tmp/*
+./ngrok*

lib/shopify-cli/commands/tunnel.rb

@@ -7,8 +7,17 @@ module Commands
     class Tunnel < ShopifyCli::Command
       # subcommands :start, :stop
 
-      def call(_args, _name)
-        puts CLI::UI.fmt(self.class.help)
+      def call(args, _name)
+        subcommand = args.shift
+        task = ShopifyCli::Tasks::Tunnel.new
+        case subcommand
+        when 'start'
+          task.call(@ctx)
+        when 'stop'
+          task.stop(@ctx)
+        else
+          puts CLI::UI.fmt(self.class.help)
+        end
       end
 
       def self.help

lib/shopify-cli/context.rb

@@ -24,7 +24,11 @@ def write(fname, content)
     end
 
     def puts(*args)
-      Kernel.puts(*args)
+      Kernel.puts(CLI::UI.fmt(*args))
+    end
+
+    def spawn(*args)
+      Kernel.spawn(*args)
     end
 
     def method_missing(method, *args)

lib/shopify-cli/tasks/tunnel.rb

@@ -1,10 +1,144 @@
+require 'json'
+require 'tempfile'
 require 'shopify_cli'
 
 module ShopifyCli
   module Tasks
     class Tunnel < ShopifyCli::Task
-      def call(ctx, *)
-        ctx.puts('success!')
+      class FetchUrlError < RuntimeError; end
+      class NgrokError < RuntimeError; end
+
+      PORT = 8081
+      DOWNLOAD_URLS = {
+        mac: 'https://bin.equinox.io/c/4VmDzA7iaHb/ngrok-stable-darwin-amd64.zip',
+      }
+      TIMEOUT = 5
+
+      def call(ctx)
+        @ctx = ctx
+        start
+      end
+
+      def stop(ctx)
+        @ctx = ctx
+        if running?
+          Process.kill(9, state[:pid])
+          FileUtils.rm(pid_file)
+          @ctx.puts("{{green:x}} ngrok tunnel stopped")
+        else
+          @ctx.puts("{{green:x}} ngrok tunnel not running")
+        end
+      end
+
+      def start
+        install
+
+        url = if running?
+          state[:url]
+        else
+          run
+        end
+        @ctx.puts("{{green:✔︎}} ngrok tunnel running at #{url}")
+        url
+      end
+
+      def run
+        pid = @ctx.spawn(ngrok_command, chdir: ShopifyCli::ROOT)
+        Process.detach(pid)
+        url = fetch_url
+        write_state(pid, url, Time.now)
+        url
+      end
+
+      private
+
+      def running?
+        if File.exist?(pid_file)
+          state = read_state
+          begin
+            Process.kill(0, state[:pid])
+            true
+          rescue Errno::ESRCH
+            false
+          rescue Errno::EPERM
+            false
+          end
+        else
+          false
+        end
+      end
+
+      def read_state
+        content = JSON.parse(File.open(pid_file).read)
+        {
+          pid: content['pid'],
+          url: content['url'],
+          time: content['time'],
+        }
+      end
+
+      def write_state(pid, url, time)
+        File.open(pid_file, 'w') do |f|
+          f.write({
+            pid: pid,
+            url: url,
+            time: time,
+          }.to_json)
+        end
+      end
+
+      def install
+        return if File.exist?(File.join(ShopifyCli::ROOT, 'ngrok'))
+        spinner = CLI::UI::SpinGroup.new
+        spinner.add('Installing ngrok...') do
+          zip_dest = File.join(ShopifyCli::ROOT, 'ngrok.zip')
+          unless File.exist?(zip_dest)
+            @ctx.system('curl', '-o', zip_dest, DOWNLOAD_URLS[:mac], chdir: ShopifyCli::ROOT)
+          end
+          @ctx.system('unzip', '-u', zip_dest, chdir: ShopifyCli::ROOT)
+          FileUtils.rm(zip_dest)
+        end
+        spinner.wait
+      end
+
+      def fetch_url
+        counter = 0
+        while counter < TIMEOUT
+          log_content = File.read(log)
+          result = log_content.match(/msg="started tunnel".*url=(https:\/\/.+)/)
+          return result[1] if result
+
+          counter += 1
+          sleep(1)
+        end
+
+        error = log_content.scan(/msg="command failed" err="([^"]+)"/).flatten
+        unless error.empty?
+          stop(@ctx)
+          raise NgrokError, error.first
+        end
+
+        raise FetchUrlError, "Unable to fetch external url"
+      end
+
+      def ngrok_command
+        "exec #{File.join(ShopifyCli::ROOT, 'ngrok')} http -log=stdout -log-level=debug #{PORT} > #{log}"
+      end
+
+      def log
+        @log ||= begin
+          fname = File.join(ShopifyCli::ROOT, '.tmp', 'ngrok.log')
+          FileUtils.touch(fname)
+          File.join(fname)
+        end
+      end
+
+      def pid_file
+        File.join(ShopifyCli::ROOT, '.tmp/ngrok.pid')
+      end
+
+      def state
+        @state ||= read_state
       end
     end
   end

test/commands/tunnel_test.rb

@@ -0,0 +1,21 @@
+require 'test_helper'
+
+module ShopifyCli
+  module Commands
+    class TunnelTest < MiniTest::Test
+      def setup
+        @command = ShopifyCli::Commands::Tunnel.new
+      end
+
+      def test_start
+        ShopifyCli::Tasks::Tunnel.any_instance.stubs(:call)
+        @command.call(['start'], nil)
+      end
+
+      def test_stop
+        ShopifyCli::Tasks::Tunnel.any_instance.stubs(:stop)
+        @command.call(['stop'], nil)
+      end
+    end
+  end
+end

test/fixtures/ngrok.log

@@ -0,0 +1,3 @@
+t=2019-03-26T14:45:57-0400 lvl=dbug msg="start tunnel listen" obj=tunnels.session name="command_line (http)" proto=http opts="&{Hostname:example.ngrok.io Auth: Subdomain: HostHeaderRewrite:false LocalURLScheme:http}" err=nil
+t=2019-03-26T14:45:57-0400 lvl=info msg="started tunnel" obj=tunnels name="command_line (http)" addr=http://localhost:8081 url=http://example.ngrok.io
+t=2019-03-26T14:45:57-0400 lvl=info msg="started tunnel" obj=tunnels name=command_line addr=http://localhost:8081 url=https://example.ngrok.io

test/fixtures/ngrok_error.log

@@ -0,0 +1 @@
+t=2019-01-04T10:03:57-0500 lvl=crit msg="command failed" err="Tunnel session failed: Your account may not run more than 8 tunnels over a single ngrok client session."

test/shopify-cli/command_registry_test.rb

@@ -5,7 +5,6 @@ class CommandRegistryTest < MiniTest::Test
 
     class FakeCommand < ShopifyCli::Command
       prerequisite_task :fake_task
-      attr_accessor :ctx
 
       def call(_args, _name)
         @ctx.puts('command!')

test/task/tunnel_test.rb

@@ -0,0 +1,72 @@
+require 'test_helper'
+
+module ShopifyCli
+  module Tasks
+    class TunnelTest < MiniTest::Test
+      include TestHelpers::Context
+
+      def setup
+        ShopifyCli::Tasks::Tunnel.any_instance.stubs(:pid_file).returns(pid_path)
+        super
+        FakeFS::FileSystem.clone(pid_path)
+      end
+
+      def test_start_running_returns_url
+        stub_binary
+        ShopifyCli::Tasks::Tunnel.any_instance.stubs(:running?).returns(true)
+        ShopifyCli::Tasks::Tunnel.any_instance.stubs(:state).returns(
+          url: 'https://example.ngrok.io',
+        )
+        assert_equal 'https://example.ngrok.io', ShopifyCli::Tasks::Tunnel.new.call(@context)
+      end
+
+      def test_start_not_running_returns_starts_ngrok
+        binary = stub_binary
+        ShopifyCli::Tasks::Tunnel.any_instance.stubs(:running?).returns(false)
+        with_log do |log_path|
+          @context.expects(:spawn).with(
+            "exec #{binary} http -log=stdout -log-level=debug 8081 > #{log_path}",
+            chdir: ShopifyCli::ROOT
+          ).returns(1000)
+          Process.expects(:detach).with(1000)
+          @context.expects(:puts).with(
+            "{{green:✔︎}} ngrok tunnel running at https://example.ngrok.io"
+          )
+          assert_equal 'https://example.ngrok.io', ShopifyCli::Tasks::Tunnel.new.call(@context)
+        end
+      end
+
+      def test_start_raises_error_on_ngrok_failure
+        binary = stub_binary
+        ShopifyCli::Tasks::Tunnel.any_instance.stubs(:running?).returns(false)
+        with_log('ngrok_error') do |log_path|
+          @context.expects(:spawn).with(
+            "exec #{binary} http -log=stdout -log-level=debug 8081 > #{log_path}",
+            chdir: ShopifyCli::ROOT
+          ).returns(1000)
+          assert_raises ShopifyCli::Tasks::Tunnel::NgrokError do
+            ShopifyCli::Tasks::Tunnel.new.call(@context)
+          end
+        end
+      end
+
+      def with_log(fixture = 'ngrok')
+        log_path = File.join(File.absolute_path(File.dirname(__FILE__)), "../fixtures/#{fixture}.log")
+        FakeFS::FileSystem.clone(log_path)
+        ShopifyCli::Tasks::Tunnel.any_instance.stubs(:log).returns(log_path)
+        yield(log_path)
+      end
+
+      def stub_binary
+        ShopifyCli::Tasks::Tunnel.any_instance.stubs(:install)
+        binary = File.join(ShopifyCli::ROOT, 'ngrok')
+        FakeFS::FileSystem.clone(binary)
+        binary
+      end
+
+      def pid_path
+        @pid_path ||= File.join(File.absolute_path(File.dirname(__FILE__)), '../fixtures/ngrok.pid')
+      end
+    end
+  end
+end