SAMのインストール
「[AWS] Serverless Application Model (SAM) でAPI Gateway + Lambda + DynamoDBなサンプルを作成してみる」を参照ください。
なお、今回のサンプルに限っていうと、DynamoDBをローカルに持つ必要はないので、Dockerのインストールは不要です。
プロジェクトの作成
では、例によって、HelloWorldベースのプロジェクトを作成していきましょう。
$ sam init --runtime=python3.8
Which template source would you like to use?
1 - AWS Quick Start Templates
2 - Custom Template Location
Choice: 1
Project name [sam-app]:
Cloning app templates from https://github.com/awslabs/aws-sam-cli-app-templates.git
AWS quick start application templates:
1 - Hello World Example
2 - EventBridge Hello World
3 - EventBridge App from scratch (100+ Event Schemas)
4 - Step Functions Sample App (Stock Trader)
5 - Elastic File System Sample App
Template selection: 1
-----------------------
Generating application:
-----------------------
Name: sam-app
Runtime: python3.8
Dependency Manager: pip
Application Template: hello-world
Output Directory: .
Next steps can be found in the README file at ./sam-app/README.md
Layerを定義する
まず、Layer用のディレクトリを作成します。
ディレクトリは、プロジェクト直下で、ディレクトリ名は後ほど定義に記述するので、自由につけて大丈夫です。
とりあえず「hello_world_layer」とでもしておきます。
$ mkdir hello_world_layer
続いて、template.yamlのResources配下に、Layerの定義を追記します。
今回は「HelloWorldLayer」という名称で作成しておきます。
template.yml変更前
Resources:
HelloWorldFunction:
Type: AWS::Serverless::Function # More info about Function Resource: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
Properties:
CodeUri: hello_world/
Handler: app.lambda_handler
Runtime: python3.8
Events:
HelloWorld:
Type: Api # More info about API Event Source: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#api
Properties:
Path: /hello
Method: get
template.yml変更後
Resources:
HelloWorldFunction:
Type: AWS::Serverless::Function # More info about Function Resource: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
Properties:
CodeUri: hello_world/
Handler: app.lambda_handler
Runtime: python3.8
Events:
HelloWorld:
Type: Api # More info about API Event Source: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#api
Properties:
Path: /hello
Method: get
Layers:
- !Ref HelloWorldLayer
HelloWorldLayer:
Type: AWS::Serverless::LayerVersion
Properties:
Description: Layer description
ContentUri: hello_world_layer/
CompatibleRuntimes:
- python3.8
Metadata:
BuildMethod: python3.8
NumPyを追加してみる
次に、ライブラリを追加します。
利用したいライブラリを記述してください。
今回のサンプルでは、機械学習でよく使用する数値計算モジュールのNumPyを追加してみたいと思います。
hello_world_layerに、requirements.txtを作成し、以下のように記述して、ライブラリを追加します。
$ touch hello_world_layer/requirements.txt
hello_world_layer/requirements.txt
numpy
Layerクラスを作成する
hello_world_layer配下に、numpyの処理をするユーザクラスを作成してみましょう。
名前は適当にuser_numpyとでもしておきましょうか。
$ touch hello_world_layer/user_numpy.py
hello_world_layer/user_numpy.py
import numpy as np
class UserNumpy():
def __init__(self):
super().__init__()
def array(self):
return np.array([0,1,2])
Layerクラスのメソッドを呼び出す
最後に、Functionの方で、追加したLayerメソッドを呼び出してみましょう。
既存のhello_world/app.pyを以下のように変更してみましょう。
helloi_world/app.py
import json
from user_numpy import UserNumpy
def lambda_handler(event, context):
un = UserNumpy()
un_str = [str(n) for n in un.array()]
return {
"statusCode": 200,
"body": json.dumps({
"message": ','.join(un_str)
}),
}
UserNumpyのarrayメソッドは、Numpyのarray([0,1,2])の結果を返します。
これは数値の配列なので、一度文字列の配列に変換したあとで、文字列かしてJsonデータとして返すようにしています。
ビルド
では、ビルドしてみましょう。
$ sam build
Building function 'HelloWorldFunction'
Running PythonPipBuilder:ResolveDependencies
Running PythonPipBuilder:CopySource
Building layer 'HelloWorldLayer'
Running PythonPipBuilder:ResolveDependencies
Running PythonPipBuilder:CopySource
Build Succeeded
Built Artifacts : .aws-sam/build
Built Template : .aws-sam/build/template.yaml
Commands you can use next
=========================
[*] Invoke Function: sam local invoke
[*] Deploy: sam deploy --guided
デプロイ
次にデプロイです。
事前に、AWSのクレデンシャルを設定しておいてください。
$ sam deploy --guided
Configuring SAM deploy
======================
Looking for samconfig.toml : Found
Reading default arguments : Success
Setting default arguments for 'sam deploy'
=========================================
Stack Name [sam-app]:
AWS Region [us-east-1]: ap-northeast-1
#Shows you resources changes to be deployed and require a 'Y' to initiate deploy
Confirm changes before deploy [Y/n]: y
#SAM needs permission to be able to create roles to connect to the resources in your template
Allow SAM CLI IAM role creation [Y/n]: y
HelloWorldFunction may not have authorization defined, Is this okay? [y/N]: y
Save arguments to samconfig.toml [Y/n]: y
Looking for resources needed for deployment: Not found.
Creating the required resources...
Successfully created!
Managed S3 bucket: aws-sam-cli-managed-default-samclisourcebucket-fqjmg5s30i1w
A different default S3 bucket can be set in samconfig.toml
Deploying with following values
===============================
Stack name : sam-app
Region : ap-northeast-1
Confirm changeset : True
Deployment s3 bucket : aws-sam-cli-managed-default-samclisourcebucket-fqjmg5s30i1w
Capabilities : ["CAPABILITY_IAM"]
Parameter overrides : {}
Initiating deployment
=====================
Saved arguments to config file
Running 'sam deploy' for future deployments will use the parameters saved above.
The above parameters can be changed by modifying samconfig.toml
Learn more about samconfig.toml syntax at
https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-cli-config.html
Uploading to sam-app/ec3e7cb3e8873a2b56d81ae66ba15ec5 262144 / 538577.0 (48.67Uploading to sam-app/ec3e7cb3e8873a2b56d81ae66ba15ec5 524288 / 538577.0 (97.35Uploading to sam-app/ec3e7cb3e8873a2b56d81ae66ba15ec5 538577 / 538577.0 (100.00%)
Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 262144 / 14534393.0 (1.8Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 524288 / 14534393.0 (3.6Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 786432 / 14534393.0 (5.4Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 1048576 / 14534393.0 (7.Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 1310720 / 14534393.0 (9.Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 1572864 / 14534393.0 (10Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 1835008 / 14534393.0 (12Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 2097152 / 14534393.0 (14Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 2359296 / 14534393.0 (16Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 2621440 / 14534393.0 (18Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 2883584 / 14534393.0 (19Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 3145728 / 14534393.0 (21Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 3407872 / 14534393.0 (23Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 3670016 / 14534393.0 (25Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 3932160 / 14534393.0 (27Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 4194304 / 14534393.0 (28Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 4456448 / 14534393.0 (30Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 4718592 / 14534393.0 (32Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 4980736 / 14534393.0 (34Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 5242880 / 14534393.0 (36Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 5505024 / 14534393.0 (37Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 5767168 / 14534393.0 (39Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 6029312 / 14534393.0 (41Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 6145785 / 14534393.0 (42Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 6407929 / 14534393.0 (44Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 6670073 / 14534393.0 (45Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 6932217 / 14534393.0 (47Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 7194361 / 14534393.0 (49Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 7456505 / 14534393.0 (51Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 7718649 / 14534393.0 (53Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 7980793 / 14534393.0 (54Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 8242937 / 14534393.0 (56Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 8505081 / 14534393.0 (58Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 8767225 / 14534393.0 (60Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 9029369 / 14534393.0 (62Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 9291513 / 14534393.0 (63Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 9553657 / 14534393.0 (65Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 9815801 / 14534393.0 (67Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 10077945 / 14534393.0 (6Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 10340089 / 14534393.0 (7Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 10602233 / 14534393.0 (7Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 10864377 / 14534393.0 (7Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 11126521 / 14534393.0 (7Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 11388665 / 14534393.0 (7Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 11650809 / 14534393.0 (8Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 11912953 / 14534393.0 (8Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 12175097 / 14534393.0 (8Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 12437241 / 14534393.0 (8Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 12699385 / 14534393.0 (8Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 12961529 / 14534393.0 (8Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 13223673 / 14534393.0 (9Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 13485817 / 14534393.0 (9Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 13747961 / 14534393.0 (9Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 14010105 / 14534393.0 (9Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 14272249 / 14534393.0 (9Uploading to sam-app/04efcd43f42b7344dff7e02a5e9d321c 14534393 / 14534393.0 (100.00%)
Deploying with following values
===============================
Stack name : sam-app
Region : ap-northeast-1
Confirm changeset : True
Deployment s3 bucket : aws-sam-cli-managed-default-samclisourcebucket-fqjmg5s30i1w
Capabilities : ["CAPABILITY_IAM"]
Parameter overrides : {}
Initiating deployment
=====================
HelloWorldFunction may not have authorization defined.
Uploading to sam-app/5c2143d527c3bab330c5c2145019dcb1.template 1455 / 1455.0 (100.00%)
Waiting for changeset to be created..
CloudFormation stack changeset
------------------------------------------------------------------------------------------------
Operation LogicalResourceId ResourceType
------------------------------------------------------------------------------------------------
+ Add HelloWorldFunctionHelloWorldPe AWS::Lambda::Permission
rmissionProd
+ Add HelloWorldFunctionRole AWS::IAM::Role
+ Add HelloWorldFunction AWS::Lambda::Function
+ Add HelloWorldLayer8a10103d68 AWS::Lambda::LayerVersion
+ Add ServerlessRestApiDeployment47f AWS::ApiGateway::Deployment
c2d5f9d
+ Add ServerlessRestApiProdStage AWS::ApiGateway::Stage
+ Add ServerlessRestApi AWS::ApiGateway::RestApi
------------------------------------------------------------------------------------------------
Changeset created successfully. arn:aws:cloudformation:ap-northeast-1:************:changeSet/samcli-deploy1597147509/8e325896-aa90-4379-afa2-44147e907291
Previewing CloudFormation changeset before deployment
======================================================
Deploy this changeset? [y/N]: y
2020-08-11 21:05:21 - Waiting for stack create/update to complete
CloudFormation events from changeset
-------------------------------------------------------------------------------------------------
ResourceStatus ResourceType LogicalResourceId ResourceStatusReason
-------------------------------------------------------------------------------------------------
CREATE_IN_PROGRESS AWS::Lambda::LayerVers HelloWorldLayer8a10103 -
ion d68
CREATE_IN_PROGRESS AWS::IAM::Role HelloWorldFunctionRole Resource creation
Initiated
CREATE_IN_PROGRESS AWS::IAM::Role HelloWorldFunctionRole -
CREATE_IN_PROGRESS AWS::Lambda::LayerVers HelloWorldLayer8a10103 Resource creation
ion d68 Initiated
CREATE_COMPLETE AWS::Lambda::LayerVers HelloWorldLayer8a10103 -
ion d68
CREATE_COMPLETE AWS::IAM::Role HelloWorldFunctionRole -
CREATE_IN_PROGRESS AWS::Lambda::Function HelloWorldFunction -
CREATE_IN_PROGRESS AWS::Lambda::Function HelloWorldFunction Resource creation
Initiated
CREATE_COMPLETE AWS::Lambda::Function HelloWorldFunction -
CREATE_IN_PROGRESS AWS::ApiGateway::RestA ServerlessRestApi -
pi
CREATE_IN_PROGRESS AWS::ApiGateway::RestA ServerlessRestApi Resource creation
pi Initiated
CREATE_COMPLETE AWS::ApiGateway::RestA ServerlessRestApi -
pi
CREATE_IN_PROGRESS AWS::ApiGateway::Deplo ServerlessRestApiDeplo -
yment yment47fc2d5f9d
CREATE_IN_PROGRESS AWS::Lambda::Permissio HelloWorldFunctionHell Resource creation
n oWorldPermissionProd Initiated
CREATE_IN_PROGRESS AWS::Lambda::Permissio HelloWorldFunctionHell -
n oWorldPermissionProd
CREATE_COMPLETE AWS::ApiGateway::Deplo ServerlessRestApiDeplo -
yment yment47fc2d5f9d
CREATE_IN_PROGRESS AWS::ApiGateway::Deplo ServerlessRestApiDeplo Resource creation
yment yment47fc2d5f9d Initiated
CREATE_IN_PROGRESS AWS::ApiGateway::Stage ServerlessRestApiProdS -
tage
CREATE_IN_PROGRESS AWS::ApiGateway::Stage ServerlessRestApiProdS Resource creation
tage Initiated
CREATE_COMPLETE AWS::ApiGateway::Stage ServerlessRestApiProdS -
tage
CREATE_COMPLETE AWS::Lambda::Permissio HelloWorldFunctionHell -
n oWorldPermissionProd
CREATE_COMPLETE AWS::CloudFormation::S sam-app -
tack
-------------------------------------------------------------------------------------------------
CloudFormation outputs from deployed stack
-------------------------------------------------------------------------------------------------
Outputs
-------------------------------------------------------------------------------------------------
Key HelloWorldFunctionIamRole
Description Implicit IAM Role created for Hello World function
Value arn:aws:iam::************:role/sam-app-HelloWorldFunctionRole-9AHTS9BZMUQL
Key HelloWorldApi
Description API Gateway endpoint URL for Prod stage for Hello World function
Value https://co2snvo0lk.execute-api.ap-northeast-1.amazonaws.com/Prod/hello/
Key HelloWorldFunction
Description Hello World Lambda Function ARN
Value arn:aws:lambda:ap-northeast-1:************:function:sam-app-
HelloWorldFunction-1GVL3Y25TQYGZ
-------------------------------------------------------------------------------------------------
Successfully created/updated stack - sam-app in ap-northeast-1
実行
最後に、Deploy時に出力されるAPI Gatewayのエンドポイントにアクセスしてみます。
$ curl https://co2snvo0lk.execute-api.ap-northeast-1.amazonaws.com/Prod/hello/
{"message": "0,1,2"}
レスポンスに、array([0,1,2])の結果が文字列として返されていることが確認できましたね！！
まとめ
Layerにライブラリを追加し、それを呼び出す共通モジュールを作ることは、簡単であることがわかったと思います。
サーバーレスの場合、なるべく疎結合に設計するのが望ましいですが、同一ドメイン内での共通ロジックをLayerに配置すること自体は間違いではないと思います。
ただし、Lambdaの制約として
- デプロイパッケージサイズ
- 圧縮済みで50MB
- 解凍後さで250MB
という制約がありますので、これを考慮しながら、必要なライブラリのみを取り込むようにしましょう。