Merge pull request #110 from janost/ssh

SSH functionality

docs/example.md

@@ -135,3 +135,9 @@ Tear down your stack by running the following command:
 ```shell
 bundle exec bin/environment delete
 ```
+
+SSH into the first instance in your stack by running the following command:
+
+```shell
+bundle exec bin/environment ssh
+```

docs/plugins.md

@@ -22,6 +22,8 @@ methods:
 - post_status
 - pre_doctor
 - post_doctor
+- pre_ssh
+- post_ssh
 
 The method will be handed a single argument, which is an instance of the
 `Moonshot::Resources` class. This instance gives the plugin access to three

docs/user-guide/cli.md

@@ -285,3 +285,32 @@ CodeDeploy
   ✓ CodeDeployRole exists.
   ✓ Resource 'AutoScalingGroup' exists in the CloudFormation template.
 ```
+
+## SSH
+
+SSH into the first or specified instance on the stack.
+
+|Description|Long Form|Short Form|Type|Example|Default|
+|---|---|---|---|---|---|
+|SSH user name|user|l|string|someuser|Environment variable: MOONSHOT_SSH_USER or USER|
+|Private key file for SSH|identity-file|i|string|~/.ssh/whatever|Environment variable: MOONSHOT_SSH_KEY_FILE|
+|Instance ID|instance|s|string|i-04683a82f2dddcc04|(first)|
+|Command to execute|command|c|string|uname -a|open a shell|
+|Auto Scaling Group|auto-scaling-group|g|string|ExampleAppAsg||
+|Environment Name|name|n|string|moonshot-sample-app|None|
+|Interactive Logger|interactive_logger||boolean||true|
+|Verbose|verbose|v|boolean||false|
+
+Example:
+
+```shell
+./bin/environment ssh --name my-service-staging -i ~/.ssh/whatever -c "cat /etc/redhat-release"
+```
+
+Output:
+
+```shell
+Opening SSH connection to i-04683a82f2dddcc04 (123.123.123.123)...
+CentOS Linux release 7.2.1511 (Core)
+Connection to 123.123.123.123 closed.
+```

lib/moonshot/cli.rb

@@ -47,6 +47,24 @@ def inherited(base)
         base.include(Moonshot::BuildMechanism)
         base.include(Moonshot::DeploymentMechanism)
       end
+
+      def ssh_options!
+        option :user, default: ENV['MOONSHOT_SSH_USER'] || ENV['USER'], type: :string,
+                      aliases: '-l',
+                      desc: 'Specifies the user to log in as on the remote machine.'
+        option :identity_file, default: ENV['MOONSHOT_SSH_KEY_FILE'], type: :string,
+                               aliases: '-i',
+                               desc: 'Selects a file from which the identity (private key) for '\
+                                     'public key authentication is read.'
+        option :instance, default: nil, type: :string, aliases: '-s',
+                          desc: 'Connect to specified instance ID instead of the first one.'
+        option :command, default: nil, type: :string, aliases: '-c',
+                         desc: 'Execute the specified command instead of opening a shell.'
+        option :auto_scaling_group, default: nil, type: :string, aliases: '-g',
+                                    desc: 'The logical ID of the auto scaling group to SSH into. '\
+                                    'Mandatory if the stack has multiple ASGs, '\
+                                    'ignored if you have only one.'
+      end
     end
 
     def initialize(*args)
@@ -91,6 +109,12 @@ def controller # rubocop:disable AbcSize, CyclomaticComplexity, PerceivedComplex
           parameter_strategy = options[:parameter_strategy] || self.class.default_parameter_strategy
           config.parameter_strategy = parameter_strategy_factory(parameter_strategy) \
             unless parameter_strategy.nil?
+
+          config.ssh_user = options[:user]
+          config.ssh_identity_file = options[:identity_file]
+          config.ssh_instance = options[:instance]
+          config.ssh_command = options[:command]
+          config.ssh_auto_scaling_group_name = options[:auto_scaling_group]
         end
       rescue => e
         raise Thor::Error, e.message
@@ -106,6 +130,12 @@ def parameter_strategy_factory(value)
           raise Thor::Error, "Unknown parameter strategy: #{value}"
         end
       end
+
+      def ssh_command(command)
+        arguments = ARGV.drop(1)
+        arguments += ['--command', command]
+        invoke :ssh, [], arguments
+      end
     end
 
     desc :list, 'List stacks for this application.'
@@ -180,5 +210,11 @@ def doctor
       success = controller.doctor
       raise Thor::Error, 'One or more checks failed.' unless success
     end
+
+    desc :ssh, 'SSH into the first or specified instance on the stack.'
+    ssh_options!
+    def ssh
+      controller.ssh
+    end
   end
 end

lib/moonshot/controller.rb

@@ -80,6 +80,12 @@ def doctor
       success
     end
 
+    def ssh
+      run_plugins(:pre_ssh)
+      stack.ssh
+      run_plugins(:post_ssh)
+    end
+
     def stack
       @stack ||= Stack.new(stack_name,
                            app_name: @config.app_name,
@@ -88,6 +94,11 @@ def stack
         config.parent_stacks = @config.parent_stacks
         config.show_all_events = @config.show_all_stack_events
         config.parameter_strategy = @config.parameter_strategy
+        config.ssh_user = @config.ssh_user
+        config.ssh_identity_file = @config.ssh_identity_file
+        config.ssh_instance = @config.ssh_instance
+        config.ssh_command = @config.ssh_command
+        config.ssh_auto_scaling_group_name = @config.ssh_auto_scaling_group_name
       end
     end
 

lib/moonshot/controller_config.rb

@@ -15,6 +15,11 @@ class ControllerConfig
     attr_accessor :plugins
     attr_accessor :show_all_stack_events
     attr_accessor :parameter_strategy
+    attr_accessor :ssh_instance
+    attr_accessor :ssh_identity_file
+    attr_accessor :ssh_user
+    attr_accessor :ssh_command
+    attr_accessor :ssh_auto_scaling_group_name
 
     def initialize
       @auto_prefix_stack = true

lib/moonshot/stack.rb

@@ -93,6 +93,18 @@ def status
       end
     end
 
+    def ssh
+      box_id = @config.ssh_instance || instances.sort.first
+      box_ip = instance_ip(box_id)
+      cmd = ['ssh', '-t']
+      cmd << "-i #{@config.ssh_identity_file}" if @config.ssh_identity_file
+      cmd << "-l #{@config.ssh_user}" if @config.ssh_user
+      cmd << box_ip
+      cmd << @config.ssh_command if @config.ssh_command
+      puts "Opening SSH connection to #{box_id} (#{box_ip})..."
+      exec(cmd.join(' '))
+    end
+
     def parameters
       get_stack(@name)
         .parameters
@@ -176,6 +188,37 @@ def add_parameter_overrides(hash)
 
     private
 
+    def asgs
+      resources_of_type('AWS::AutoScaling::AutoScalingGroup')
+    end
+
+    def instance_ip(instance_id)
+      Aws::EC2::Client.new.describe_instances(instance_ids: [instance_id])
+                      .reservations.first.instances.first.public_ip_address
+    rescue
+      raise "Failed to determine public IP address for instance #{instance_id}."
+    end
+
+    def instances # rubocop:disable Metrics/AbcSize
+      groups = asgs
+      asg = if groups.count == 1
+              groups.first
+            elsif asgs.count > 1
+              unless @config.ssh_auto_scaling_group_name
+                raise 'Multiple Auto Scaling Groups found in the stack. Please specify which '\
+                      'one to SSH into using the --auto-scaling-group (-g) option.'
+              end
+              groups.detect { |x| x.logical_resource_id == @config.ssh_auto_scaling_group_name }
+            end
+      raise 'Failed to find the Auto Scaling Group.' unless asg
+
+      Aws::AutoScaling::Client.new.describe_auto_scaling_groups(
+        auto_scaling_group_names: [asg.physical_resource_id]
+      ).auto_scaling_groups.first.instances.map(&:instance_id)
+    rescue
+      raise 'Failed to find instances in the Auto Scaling Group.'
+    end
+
     def stack_name
       "CloudFormation Stack #{@name.blue}"
     end

lib/moonshot/stack_config.rb

@@ -4,6 +4,11 @@ class StackConfig
     attr_accessor :parent_stacks
     attr_accessor :show_all_events
     attr_accessor :parameter_strategy
+    attr_accessor :ssh_instance
+    attr_accessor :ssh_identity_file
+    attr_accessor :ssh_user
+    attr_accessor :ssh_command
+    attr_accessor :ssh_auto_scaling_group_name
 
     def initialize
       @parent_stacks = []

spec/moonshot/stack_spec.rb

@@ -9,6 +9,10 @@
   subject do
     described_class.new('test', app_name: 'rspec-app', log: log, ilog: ilog) do |c|
       c.parent_stacks = parent_stacks
+      c.ssh_instance = 'i-04683a82f2dddcc04'
+      c.ssh_identity_file = '~/.ssh/whatever'
+      c.ssh_user = 'username'
+      c.ssh_command = 'uname -a'
     end
   end
 
@@ -139,4 +143,15 @@
       expect(subject.parameters_file).to eq(path)
     end
   end
+
+  describe '#ssh' do
+    it 'should execute an ssh command with proper parameters' do
+      allow(subject).to receive(:instance_ip).and_return('123.123.123.123')
+      expect(STDOUT).to receive(:puts).with('Opening SSH connection to i-04683a82f2dddcc04 '\
+                                            '(123.123.123.123)...')
+      expect(subject).to receive('exec').with('ssh -t -i ~/.ssh/whatever -l username '\
+                                              '123.123.123.123 uname -a')
+      subject.ssh
+    end
+  end
 end