Module: AwsStackBuilder

Defined in:
lib/lambda/aws_stack_builder.rb,
lib/lambda/aws_stack_uploader.rb

Constant Summary collapse

RUBY_VERSION = 
'ruby2.5'
GEM_PATH = 
'/opt/ruby/2.5.0'
LAMBDA_HANDLER_FILE_NAME = 
'lambda-handler'
S3Client = 
Aws::S3::Client.new

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.api_gateway_deployment ⇒ Object

Returns the value of attribute api_gateway_deployment.



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# File 'lib/lambda/aws_stack_builder.rb', line 12

def api_gateway_deployment
  @api_gateway_deployment
end

.app_dir ⇒ Object

Returns the value of attribute app_dir.



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# File 'lib/lambda/aws_stack_builder.rb', line 12

def app_dir
  @app_dir
end

.app_name ⇒ Object

Returns the value of attribute app_name.



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# File 'lib/lambda/aws_stack_builder.rb', line 12

def app_name
  @app_name
end

.app_path ⇒ Object

Returns the value of attribute app_path.



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# File 'lib/lambda/aws_stack_builder.rb', line 12

def app_path
  @app_path
end

.bucket ⇒ Object

Returns the value of attribute bucket.



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# File 'lib/lambda/aws_stack_builder.rb', line 12

def bucket
  @bucket
end

.gateway_id ⇒ Object

Returns the value of attribute gateway_id.



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# File 'lib/lambda/aws_stack_builder.rb', line 12

def gateway_id
  @gateway_id
end

.stack ⇒ Object

Returns the value of attribute stack.



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# File 'lib/lambda/aws_stack_builder.rb', line 12

def stack
  @stack
end

.stack_opts ⇒ Object

Returns the value of attribute stack_opts.



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# File 'lib/lambda/aws_stack_builder.rb', line 12

def stack_opts
  @stack_opts
end

Class Method Details

.add_api_gateway ⇒ Object

gateway



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# File 'lib/lambda/aws_stack_builder.rb', line 56

def add_api_gateway
  @gateway_id = 'ApiGateway'
  @stack.add(gateway_id, Humidifier::ApiGateway::RestApi.new(name: app_name, description: app_name + ' API'))
end

.add_api_gateway_deployment ⇒ Object

gateway deployment



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# File 'lib/lambda/aws_stack_builder.rb', line 62

def add_api_gateway_deployment
  @api_gateway_deployment = Humidifier::ApiGateway::Deployment.new(
    rest_api_id: Humidifier.ref(gateway_id),
    stage_name: Humidifier.ref("ApiGatewayStageName")
  )
  @stack.add('ApiGatewayDeployment', @api_gateway_deployment)
  @stack.add_output('ApiGatewayInvokeURL',
      value: Humidifier.fn.sub("https://${#{gateway_id}}.execute-api.${AWS::Region}.amazonaws.com/${ApiGatewayStageName}"),
      description: 'API root url',
      export_name: app_name + 'RootUrl'
  )
  @api_gateway_deployment.depends_on = []
end

.add_api_gateway_resources(gateway:, lambda:) ⇒ Object

gateway method



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# File 'lib/lambda/aws_stack_builder.rb', line 129

def add_api_gateway_resources(gateway:, lambda:)

  # example: calculator/algebra/:x/:y/sum -> module name, args, method name
  path = gateway[:path].split('/')

  # root resource
  root_resource = path.shift
  @stack.add(root_resource.camelize, Humidifier::ApiGateway::Resource.new(
      rest_api_id: Humidifier.ref(AwsStackBuilder.gateway_id),
      parent_id: Humidifier.fn.get_att(["ApiGateway", "RootResourceId"]),
      path_part: root_resource
    )
  )

  # args and method name are nested resources
  parent_resource = root_resource.camelize
  path.each do |fragment|
    if fragment.start_with?(':')
      fragment = fragment[1..-1]
      dynamic_fragment = "{#{fragment}}"
    end
    @stack.add(parent_resource + fragment.camelize, Humidifier::ApiGateway::Resource.new(
        rest_api_id: Humidifier.ref(AwsStackBuilder.gateway_id),
        parent_id: Humidifier.ref(parent_resource),
        path_part: dynamic_fragment || fragment
      )
    )
    parent_resource = parent_resource + fragment.camelize
  end

  # attach lambda to last resource
  id = 'EndpointFor' + (gateway[:path].gsub(':', '').gsub('/', '_')).camelize
  @stack.add(id, Humidifier::ApiGateway::Method.new(
      authorization_type: 'NONE',
      http_method: gateway[:verb].to_s.upcase,
      integration: {
        integration_http_method: 'POST',
        type: "AWS_PROXY",
        uri: Humidifier.fn.sub([
          "arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${lambdaArn}/invocations",
          'lambdaArn' => Humidifier.fn.get_att([lambda, 'Arn'])
        ])
      },
      rest_api_id: Humidifier.ref(gateway_id),
      resource_id: Humidifier.ref(parent_resource) # last evaluated resource
    )
  )

  # deployment depends on the method
  @api_gateway_deployment.depends_on << id
end

.add_lambda(gateway:, mod:, wrapper: {}, env: {}, settings: {}) ⇒ Object

lambda function



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# File 'lib/lambda/aws_stack_builder.rb', line 77

def add_lambda(gateway:, mod:, wrapper: {}, env: {}, settings: {})
  lambda_config = {}
  name_parts = mod[:name].split('::')
  {gateway: gateway, module: mod, wrapper: wrapper}.each do |env_group_prefix, env_group|
    env_group.each{|env_key, env_value| lambda_config["#{env_group_prefix}_#{env_key}"] = env_value}
  end

  lambda_function = Humidifier::Lambda::Function.new(
    description: "Lambda for #{mod[:name]}.#{mod[:method]}",
    function_name: [app_name.dasherize, name_parts, mod[:method]].flatten.map(&:downcase).join('-'),
    handler: "#{LAMBDA_HANDLER_FILE_NAME}.AwsLambdaHandler.call",
    environment: {
      variables: env
        .reduce({}){|env_as_string, (k, v)| env_as_string.update(k.to_s => v.to_s)}
        .merge(lambda_config)
        .merge('GEM_PATH' => GEM_PATH, 'app_dir' => app_dir)
    },
    role: Humidifier.fn.get_att(['LambdaRole', 'Arn']),
    timeout: settings[:timeout] || stack_opts[:timeout] || 15,
    memory_size: settings[:memory_size] || stack_opts[:memory_size] || 128,
    runtime: RUBY_VERSION,
    code: {
      s3_bucket: bucket,
      s3_key: LAMBDA_HANDLER_FILE_NAME + '.rb.zip'
    },
    layers: [
      Humidifier.ref(app_name + 'Layer'),
      Humidifier.ref(app_name + 'GemsLayer')
    ]
  )
  id = ['Lambda', name_parts, mod[:method].capitalize].join
  @stack.add(id, lambda_function)
  add_lambda_invoke_permission(id: id, gateway: gateway)
  id
end

.add_lambda_iam_role(function_name: nil) ⇒ Object 



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# File 'lib/lambda/aws_stack_builder.rb', line 181

def add_lambda_iam_role(function_name: nil)
  @stack.add('LambdaRole', Humidifier::IAM::Role.new(
      assume_role_policy_document: {
        'Version' => "2012-10-17",
        'Statement' => [
          {
            'Action' => ["sts:AssumeRole"],
            'Effect' => "Allow",
            'Principal' => {
              'Service' => ["lambda.amazonaws.com"]
            }
          }
        ]
      },
      policies: [
        {
          'policy_document' => {
            'Version' => "2012-10-17",
            'Statement' => [
              {
                'Action' => [
                  "logs:CreateLogStream",
                  "logs:PutLogEvents",
                ],
                'Effect' => "Allow",
                'Resource' => Humidifier.fn.sub("arn:aws:logs:${AWS::Region}:${AWS::AccountId}:*")
              },
              {
                'Action' => [
                  "logs:CreateLogGroup",
                ],
                'Effect' => "Allow",
                'Resource' => "*"
              }
            ]
          },
          'policy_name' => "cloud-watch-access"
        }
      ]
    )
  )
end

.add_lambda_invoke_permission(id:, gateway:) ⇒ Object

invoke permission



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# File 'lib/lambda/aws_stack_builder.rb', line 114

def add_lambda_invoke_permission(id:, gateway:)
  arn_path_matcher = gateway[:path].split('/').each_with_object([]) do |fragment, matcher|
    fragment = '*' if fragment.start_with?(':')
    matcher << fragment
  end.join('/')
  @stack.add('LambdaPermission', Humidifier::Lambda::Permission.new(
      action: "lambda:InvokeFunction",
      function_name: Humidifier.fn.get_att([id, 'Arn']),
      principal: "apigateway.amazonaws.com",
      source_arn: Humidifier.fn.sub("arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${#{gateway_id}}/*/#{gateway[:verb]}/#{arn_path_matcher}")
    )
  )
end

.add_layer(name:, description:, s3_key:, s3_object_version:) ⇒ Object

add layer



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# File 'lib/lambda/aws_stack_uploader.rb', line 128

def add_layer(name:, description:, s3_key:, s3_object_version:)
  stack.add(name + 'Layer', Humidifier::Lambda::LayerVersion.new(
      compatible_runtimes: [RUBY_VERSION],
      layer_name: name,
      description: description,
      content: {
        s3_bucket: bucket,
        s3_key: s3_key,
        s3_object_version: s3_object_version
      }
    )
  )
end

.checksum(dir) ⇒ Object 



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# File 'lib/lambda/aws_stack_uploader.rb', line 142

def checksum(dir)
  files = Dir["#{dir}/**/*"].reject{|f| File.directory?(f)}
  content = files.map{|f| File.read(f)}.join
  Digest::MD5.hexdigest(content)
end

.extend_stack_instance(stack) ⇒ Object

helpers



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# File 'lib/lambda/aws_stack_builder.rb', line 44

def extend_stack_instance(stack)
  stack.instance_eval do
    def add_lambda_endpoint(**opts) # gateway:, mod:, wrapper: {}, env: {}, settings: {}
      # add lambda
      lambda = AwsStackBuilder.add_lambda(opts)
      # add api resources
      AwsStackBuilder.add_api_gateway_resources(gateway: opts[:gateway], lambda: lambda)
    end
  end
end

.init(app_name:, bucket:, **stack_opts) ⇒ Object 



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# File 'lib/lambda/aws_stack_builder.rb', line 15

def init(app_name:, bucket:, **stack_opts)
  puts 'Initializing stack'
  @app_name   = app_name.camelize
  @bucket     = bucket
  @app_path   = Pathname.getwd
  @app_dir    = app_path.basename.to_s
  @stack_opts = stack_opts
  @stack      = Humidifier::Stack.new(name: @app_name, aws_template_format_version: '2010-09-09')

  # api stage
  @stack.add_parameter('ApiGatewayStageName', description: 'Gateway deployment stage', type: 'String', default: 'v1')

  add_api_gateway
  add_api_gateway_deployment
  add_lambda_iam_role
  upload_files
  extend_stack_instance(@stack)
  @stack
end

.upload_app_layer ⇒ Object 



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# File 'lib/lambda/aws_stack_uploader.rb', line 92

def upload_app_layer
  wd = Pathname.getwd
  zip_file_name = app_dir + '.zip'
  app_zip_path  = wd.join(zip_file_name)

  # calculate checksum for app folder
  checksum_path = app_path.join('.modulator/app_checksum')
  old_checksum  = (checksum_path.read rescue nil)
  new_checksum  = checksum(app_path)

  if old_checksum != new_checksum
    puts '- uploading app layer'
    checksum_path.write(new_checksum)
    ZipFileGenerator.new(app_path, app_zip_path).write
    # upload zipped file
    app_layer = S3Client.put_object(
      bucket: bucket,
      key: zip_file_name,
      body: app_zip_path.read
    )
    # delete zipped file
    app_zip_path.delete
  else
    puts '- using existing app layer'
    app_layer = S3Client.get_object(bucket: bucket, key: zip_file_name)
  end

  add_layer(
    name: app_name,
    description: "App source. MD5: #{new_checksum}",
    s3_key: zip_file_name,
    s3_object_version: app_layer.version_id
  )
end

.upload_files ⇒ Object 



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# File 'lib/lambda/aws_stack_builder.rb', line 35

def upload_files
  upload_lambda_handler
  puts 'Generating layers'
  app_path.join('.modulator').mkpath
  upload_gems_layer
  upload_app_layer
end

.upload_gems_layer ⇒ Object 



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# File 'lib/lambda/aws_stack_uploader.rb', line 43

def upload_gems_layer
  if !app_path.join('Gemfile').exist?
    puts '- no Gemfile detected'
    return
  end

  # calculate Gemfile checksum
  checksum_path = app_path.join('.modulator/gemfile_checksum')
  old_checksum  = (checksum_path.read rescue nil)
  new_checksum  = Digest::MD5.hexdigest(File.read(app_path.join('Gemfile.lock')))

  zip_file_name = app_dir + '_gems.zip'
  gems_path = app_path.join('.modulator/gems')
  gems_zip_path = gems_path.parent.join(zip_file_name)

  if old_checksum != new_checksum
    puts '- uploading gems layer'
    checksum_path.write(new_checksum)

    # bundle gems
    Bundler.with_clean_env do
      Dir.chdir(app_path) do
        `bundle install --path=./.modulator/gems --clean`
      end
    end
    ZipFileGenerator.new(gems_path, gems_zip_path).write

    # upload zipped file
    gem_layer = S3Client.put_object(
      bucket: bucket,
      key: zip_file_name,
      body: gems_zip_path.read
    )
    # delete zipped file
    FileUtils.remove_dir(gems_path)
    gems_zip_path.delete
  else
    puts '- using existing gems layer'
    gem_layer = S3Client.get_object(bucket: bucket, key: zip_file_name)
  end

  add_layer(
    name: app_name + 'Gems',
    description: "App gems",
    s3_key: zip_file_name,
    s3_object_version: gem_layer.version_id
  )
end

.upload_lambda_handler ⇒ Object 



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# File 'lib/lambda/aws_stack_uploader.rb', line 10

def upload_lambda_handler
  bucket_name = Humidifier.ref("S3Bucket").reference
  lambda_handler_key = LAMBDA_HANDLER_FILE_NAME + '.rb.zip'
  source = <<~SOURCE
    # see handler AwsApiGatewayEventHandler.call(event: event, context: context) in required file
    require 'lambda/aws_lambda_handler'
    Dir.chdir('/opt/ruby/lib/' + ENV['app_dir'])
  SOURCE

  existing_handler = S3Client.get_object(
    bucket: bucket,
    key: lambda_handler_key
  ) rescue false # not found

  existing_source = Zip::InputStream.open(existing_handler.body) do |zip_file|
    zip_file.get_next_entry
    zip_file.read
  end if existing_handler

  if existing_source != source
    puts '- uploading generic lambda handler'
    source_zip_file = Zip::OutputStream.write_buffer do |zip|
      zip.put_next_entry LAMBDA_HANDLER_FILE_NAME + '.rb'
      zip.print source
    end
    S3Client.put_object(
      bucket: bucket,
      key: lambda_handler_key,
      body: source_zip_file.tap(&:rewind).read
    )
  end
end