I do a SAM deployment from my local console. With sam package ... --s3-bucket xy I specify the existing s3-bucket where deployment relevant objects are stored. I want that bucket to appear in the Output section in Cloudformation but I don't know how to reference it.
If I look under Template in the web console I see the path:
Resources:
MyLambda:
Properties:
CodeUri: s3://xy/1b26f7841...
So I tried to add
Outputs:
SourceBucket:
Value: !GetAtt MyLambda.Properties.CodeUri
to my template.yaml, but the deployment fails with Requested attribute Properties.CodeUri does not exist in schema for AWS::Lambda::Function
Sadly you can't do this. AWS::Serverless::Function does not return such information. You would have to use custom resource to get it.
Alternatively, if you pass the bucket uri as input parameter to your template, you can output the parameter's value directly.
I have a parameter in an aws cloudformation template
Parameters:
ExecRole:
Type: String
Description: Required. Lambda exec role ARN
Default: arn:aws:iam::123456789:role/lambdaExecRole
Assuming the 123456789 is the AcountId I want to use the pseudo parameter reference but I cannot do it, I try the followings without success
Default: arn:aws:iam::!Ref{AWS::AccountId}:role/exLambdaExecRole
Default: !Sub 'arn:aws:iam::${AWS::AccountId}:role/exLambdaExecRole'
In the last case is throwing me an error
Default member must be a string.
It seems like functions (ex. !Sub) are not supported in default values of Parameters.
Here's a workaround we're using.
We have a separate stack called Parameters which exports whatever parameters needed in other stacks. For instance:
Outputs:
VpcId:
Description: Id of the VPC.
Value: !Ref VpcId
Export:
Name: !Sub 'stk-${EnvType}-${EnvId}-VpcId'
In other stacks we simply import these exported values:
VpcId: !ImportValue
'Fn::Sub': 'stk-${EnvType}-${EnvId}-VpcId'
EnvType and EnvId are the same for all the stacks of one environment.
With roles you might want to do the following. Create a separate Roles template, implement your roles there and export their ARNs:
Outputs:
LambdaExecutionRoleArn:
Description: ARN of the execution role for the log-and-pass function.
Value: !GetAtt
- LambdaExecutionRole
- Arn
Export:
Name: !Sub 'stk-${EnvType}-${EnvId}-roles-LambdaExecutionRole-Arn'
Again, in other stack you could simply ImportValue:
Role: !ImportValue
'Fn::Sub': 'stk-${EnvType}-${EnvId}-roles-LogAndPassFunctionExecutionRole-Arn'
Assuming this will always be role, why can't you as a parameter ask for the nae to be passed in then use the Sub intrinsic function to replace in the Resources section of your CloudFormation template.
That way your arn:aws:iam::${AWS::AccountId}:role part of the arn would not need to be part of the parameter.
Given the following CloudFormation template snippet:
AWSTemplateFormatVersion: 2010-09-09
Resources:
PrototypeCreateOrderFDM4:
Type: "AWS::Lambda::Function"
Properties:
CodeUri: "../Lambda/"
Handler: "PrototypeCreateOrder.handler"
Timeout: 15
Runtime: "nodejs10.x"
Role: arn:aws:iam::123456789012:role/deezNutz-Role-1ABC8DDEFGHI
I'm getting a warning saying that the CodeURI isn't a valid property:
I have lots of other Lambda's structure like this. I've never gotten this before. What am I missing?
You're using the AWS::Lambda::Function resource, which doesn't have a CodeUri property.
You're probably thinking of the AWS::Serverless::Function from SAM, which supports a CodeUri property.
However, with SAM, you can omit the CodeUri property if your Lambda code is local to your template (and if your handler is under Lambda/index.js, then you can just point the Handler: property to the path directly). Can't say for sure if this will work with AWS::Lambda::Function, but will definitely with SAM's AWS::Serverless::Function.
I'm finding it hard to understand the difference between SAM template and Cloudformation template. I know that SAM template can be used to define Serverless Applications like Lambda, but how does that make it different from Cloudformation template? Is the syntax different? I can still specify the Lambda definitions in cloudformation template. So, my question is why should I care about SAM? Won't knowing about just cloud formation template be sufficient?
From CloudFormation's perspective, SAM is a transform. Meaning: SAM templates are syntactically equivalent, but they allow you to define your serverless app with more brevity. The SAM template eventually gets expanded into full CFN behind the scenes. If you already know CFN, but want to write less YAML code, SAM may be beneficial to you. The idea is to reduce your effort.
SAM templates are a superset of Cloudformation. Any Cloudformation template can be run through SAM unchanged, and it will work. SAM supports all the types available in Cloudformation templates, so you can think of SAM as "CloudFormation++".
However, SAM also gives you additional "transforms" that allow you to define certain concepts succinctly, and SAM will figure out what you mean and fill in the the missing pieces to create a full, expanded, legal Cloudformation template.
Example: For SAM (and Serverless Framework) users, who deal mostly in Lambda functions, one of the more most useful transforms is the Events property on the Lambda function -- SAM will add all the objects needs to access that function through an API path in API Gateway.
Resources:
HelloWorldFunction:
Type: AWS::Serverless::Function
Properties:
CodeUri: HelloWorldFunction
Handler: app.lambdaHandler
Runtime: nodejs12.x
Events: # <--- "Events" property is not a real Cloudformation Lambda property
HelloWorld:
Type: Api
Properties:
Path: /hello
Method: get
The SAM template snippet shown above gets transformed/expanded into several API Gateway objects (a RestApi, a deployment, and a stage). The AWS::Serverless::Function type used in this snippet is not a real Cloudformation type -- you won't find it in the docs. SAM expands it into a Cloudformation template containing a AWS::Lambda::Function object and several different AWS::ApiGateway::* objects that Cloudformation understands.
To give you an idea of how much manual coding this saves you, here's what the expanded version of the above SAM template looks like as a full Cloudformation template:
Resources:
HelloWorldFunctionHelloWorldPermissionProd:
Type: AWS::Lambda::Permission
Properties:
Action: lambda:InvokeFunction
Principal: apigateway.amazonaws.com
FunctionName:
Ref: HelloWorldFunction
SourceArn:
Fn::Sub:
- arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${__ApiId__}/${__Stage__}/GET/hello
- __Stage__: "*"
__ApiId__:
Ref: ServerlessRestApi
HelloWorldFunctionRole:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Version: '2012-10-17'
Statement:
- Action:
- sts:AssumeRole
Effect: Allow
Principal:
Service:
- lambda.amazonaws.com
ManagedPolicyArns:
- arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole
Tags:
- Value: SAM
Key: lambda:createdBy
ServerlessRestApiProdStage:
Type: AWS::ApiGateway::Stage
Properties:
DeploymentId:
Ref: ServerlessRestApiDeployment_NNN
RestApiId:
Ref: ServerlessRestApi
StageName: Prod
ServerlessRestApiDeployment_NNN:
Type: AWS::ApiGateway::Deployment
Properties:
RestApiId:
Ref: ServerlessRestApi
Description: 'RestApi deployment id: ???'
StageName: Stage
ServerlessRestApi:
Type: AWS::ApiGateway::RestApi
Properties:
Body:
info:
version: '1.0'
title:
Ref: AWS::StackName
paths:
"/hello":
get:
x-amazon-apigateway-integration:
httpMethod: POST
type: aws_proxy
uri:
Fn::Sub: arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${HelloWorldFunction.Arn}/invocations
responses: {}
swagger: '2.0'
HelloWorldFunction:
Type: AWS::Lambda::Function
Properties:
Code:
S3Bucket: aws-sam-cli-managed-default-samclisourcebucket-???
S3Key: temp/???
Tags:
- Value: SAM
Key: lambda:createdBy
Handler: app.lambdaHandler
Role:
Fn::GetAtt:
- HelloWorldFunctionRole
- Arn
Timeout: 3
Runtime: nodejs12.x
Previously, if you were authoring pure Cloudformation, you would have had to code all this by hand, over and over, for each API Gateway endpoint that you wanted to create. Now, with a SAM template, you define the API as an "Event" property of the Lambda function, and SAM (or Serverless Framework) takes care of the drudgery.
In the old days, when we had to do all this by hand, it totally sucked. But now, everything is glorious again.
Like #Luis Colon said, SAM is a transform. What that means, is that at the top of a SAM Template there is a Transform statement that lets CloudFormation know to run an intrinsic function, Transform, on this SAM template to turn it into a CloudFormation template. So, all SAM Templates will eventually be converted into CF templates, but for the end-user in most cases it is easier to just use the SAM template. For instance, for a simple application with Lambdas triggered by a new API you're creating, the SAM template will let you accomplish this in fewer lines than CloudFormation.
To extend this, the Serverless Framework behaves similarly. Serverless is designed to work across platforms (AWS, Azure, etc.). It's syntax looks very similar to SAM, and it too converts the template into the target platform's (ie. AWS) fuller version of the template (ie. CloudFormation template).
You can imagine SAM as an extended form of CloudFormation. SAM makes Serverless/Lambda deployments easier.
Even CloudFormation can deploy lambda scripts using inline scripts but it has a limitation of 4096 characters and you cannot pack custom dependencies, python libraries.
So to make Lambda/Serverless deployments easy SAM is used. SAM is a CLI tool. You cannot find SAM in AWS Console.
In case of python deployment, sam will read the requirements.txt file build a package, and will deploy the package when you wish to sam deploy
So at the end of the day you can write as much lengthy Lambda Code, use as many libraries you want and even import your custom libraries i.e. complete flexibility.
I'm trying to deploy AWS Lambda function by using SAM.
What I want to do is to update exsiting lambda function by deploying local source code.
In order to do that, I specified the existing lambda function name as 'FunctionName' in template.yaml like below.
However, 'FunctionName' does only support for creating new function, not updating to existing function.
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-lambda-function.html#cfn-lambda-function-functionname
Are there any ways to specify Function Name in SAM in order to update lambda function?
[template.yaml]
AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Resources:
HelloWorld:
Type: 'AWS::Serverless::Function'
Properties:
FunctionName: 'hello_world'
Description: ''
Handler: index.handler
MemorySize: 256
Role: 'arn:aws:iam::368834739507:role/lambda_basic_execution'
Runtime: nodejs6.10
Timeout: 120
Using SAM (and/or CloudFormation), you cannot update existing resources.
SAM (and CloudFormation) create and manage their own resources. All resources specified in the template are going to be created when the stack is created. They cannot be "taken over".
Instead, you should allow SAM (or CloudFormation) to create the Lambda function for you, then update users to reference the new function. After that, you can update your code using SAM.