Please refer to "[AWS] Try to create API Gateway + Lambda + DynamoDB sample with Serverless Application Model (SAM)".
As far as this sample is concerned, it is not necessary to have DynamoDB locally, so it is not necessary to install Docker.
Now, as usual, let's create a Hello World-based project.
$ 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
First, create a directory for the layer. The directory is directly under the project, and the directory name will be described in the definition later, so you can freely add it. For the time being, let's call it "hello_world_layer".
$ mkdir hello_world_layer
Next, add the Layer definition under Resources in template.yaml.
This time, create it with the name "Hello World Layer".
template.before changing yml
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.After changing yml
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
Then add the library. Please describe the library you want to use. In this sample, I would like to add NumPy, a numerical calculation module often used in machine learning.
Create requirements.txt in hello_world_layer and write as follows to add the library.
$ touch hello_world_layer/requirements.txt
hello_world_layer/requirements.txt
numpy
Let's create a user class that processes numpy under hello_world_layer.
Should I name it appropriately as ʻuser_numpy`?
$ 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])
Finally, let's call the added Layer method on the Function side.
Let's change the existing hello_world / app.py as follows.
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's array method returns the result of Numpy's ʻarray ([0,1,2])`. Since this is an array of numbers, after converting it to an array of character strings once, it is converted to a character string and returned as Json data.
Let's build it.
$ 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
Next is deployment. Please set the AWS credentials in advance.
$ 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 [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-1:767054379442: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::767054379442: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-1:767054379442:function:sam-app-
HelloWorldFunction-1GVL3Y25TQYGZ
-------------------------------------------------------------------------------------------------
Successfully created/updated stack - sam-app in ap-northeast-1
Finally, let's access the API Gateway endpoint that is output during Deploy.
$ curl https://co2snvo0lk.execute-api.ap-northeast-1.amazonaws.com/Prod/hello/
{"message": "0,1,2"}
You can see that the result of ʻarray ([0,1,2])` is returned as a string in the response! !!
You've found it easy to add a library to a Layer and create a common module that calls it. In the case of serverless, it is desirable to design it as loosely coupled as possible, but I think that it is not a mistake to place common logic within the same domain in the layer.
However, as a Lambda constraint
--Deployment package size --Compressed and 50MB --250MB after decompression
Since there is a restriction, let's take this into consideration and import only the necessary libraries.
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