[英]Dynamic environment variables for AWS Lambda using cloudformation template
I have to use AWS lambda in various stack of my application, thus I have created a generic cloud-formation template to create a lambda function.我必须在我的应用程序的各种堆栈中使用 AWS lambda,因此我创建了一个通用的云形成模板来创建 lambda function。 This template can be included in another cloud-formation template for further use as a nested stack .此模板可以包含在另一个云形成模板中,以进一步用作嵌套堆栈。
# Basics
AWSTemplateFormatVersion: '2010-09-09'
Description: AWS CloudFormation Template to create a lambda function for java 8 or nodejs
# Parameters
Parameters:
FunctionName:
Type: String
Description: Funciton Name
HandlerName:
Type: String
Description: Handler Name
FunctionCodeS3Bucket:
Type: String
Description: Name of s3 bucket where the function code is present
Default: my-deployment-bucket
FunctionCodeS3Key:
Type: String
Description: Function code present in s3 bucket
MemorySize:
Type: Number
Description: Memory size between 128 MB - 1536 MB and multiple of 64
MinValue: '128'
MaxValue: '1536'
Default: '128'
RoleARN:
Type: String
Description: Role ARN for this function
Runtime:
Type: String
Description: Runtime Environment name e.g nodejs, java8
AllowedPattern: ^(nodejs6.10|nodejs4.3|java8)$
ConstraintDescription: must be a valid environment (nodejs6.10|nodejs4.3|java8) name.
Timeout:
Type: Number
Description: Timeout in seconds
Default: '3'
Env1:
Type: String
Description: Environment Variable with format Key|value
Default: ''
Env2:
Type: String
Description: Environment Variable with format Key|value
Default: ''
Env3:
Type: String
Description: Environment Variable with format Key|value
Default: ''
Env4:
Type: String
Description: Environment Variable with format Key|value
Default: ''
# Conditions
Conditions:
Env1Exist: !Not [ !Equals [!Ref Env1, '']]
Env2Exist: !Not [ !Equals [!Ref Env2, '']]
Env3Exist: !Not [ !Equals [!Ref Env3, '']]
Env4Exist: !Not [ !Equals [!Ref Env4, '']]
# Resources
Resources:
LambdaFunction:
Type: AWS::Lambda::Function
Properties:
Code:
S3Bucket: !Ref 'FunctionCodeS3Bucket'
S3Key: !Ref 'FunctionCodeS3Key'
Description: !Sub 'Lambda function for: ${FunctionName}'
Environment:
Variables:
'Fn::If':
- Env1Exist
-
- !Select [0, !Split ["|", !Ref Env1]]: !Select [1, !Split ["|", !Ref Env1]]
- 'Fn::If':
- Env2Exist
- !Select [0, !Split ["|", !Ref Env2]]: !Select [1, !Split ["|", !Ref Env2]]
- !Ref "AWS::NoValue"
- 'Fn::If':
- Env3Exist
- !Select [0, !Split ["|", !Ref Env3]]: !Select [1, !Split ["|", !Ref Env3]]
- !Ref "AWS::NoValue"
- 'Fn::If':
- Env4Exist
- !Select [0, !Split ["|", !Ref Env4]]: !Select [1, !Split ["|", !Ref Env4]]
- !Ref "AWS::NoValue"
- !Ref "AWS::NoValue"
FunctionName: !Ref 'FunctionName'
Handler: !Ref 'HandlerName'
MemorySize: !Ref 'MemorySize'
Role: !Ref 'RoleARN'
Runtime: !Ref 'Runtime'
Timeout: !Ref 'Timeout'
Outputs:
LambdaFunctionARN:
Value: !GetAtt 'LambdaFunction.Arn'
I want to inject the environment variables to the the function and that will be passed from parent stack as below:我想将环境变量注入 function 并将从父堆栈传递,如下所示:
# Resouces
Resources:
# Lambda for search Function
ChildStackLambdaFunction:
Type: AWS::CloudFormation::Stack
Properties:
TemplateURL: <<REF_TO_ABOVE_LAMBDA_STACK.yml>>
Parameters:
FunctionName: test
HandlerName: 'index.handler'
FunctionCodeS3Bucket: <<BUCKET_NAME>>
FunctionCodeS3Key: <<FUNCTION_DEPLOYMENT_NAME>>
MemorySize: '256'
RoleARN: <<ROLE_ARN>>
Runtime: nodejs6.10
Timeout: '60'
Env1: !Sub 'AWS_REGION|${AWS::Region}'
When I deploy this stack, I am getting below error.当我部署这个堆栈时,我遇到了错误。 Can anybody help me to resolve this one?有人可以帮我解决这个问题吗?
Template format error: [/Resources/LambdaFunction/Type/Environment/Variables/Fn::If/1/0] map keys must be strings;模板格式错误:[/Resources/LambdaFunction/Type/Environment/Variables/Fn::If/1/0] map 键必须是字符串; received a map instead收到了 map
Passing key-value parameter is referred from here传递键值参数是从这里引用的
So, I tried so many ways to achieve this, but we can not pass the dynamic key-value pair to nested lambda stack from the parent stack.所以,我尝试了很多方法来实现这一点,但我们无法将动态键值对从父堆栈传递给嵌套的 lambda 堆栈。 I had a confirmation from the AWS support that this is not possible as this moment.我得到了 AWS 支持的确认,目前这是不可能的。
They suggested a another way which I liked and implemented and its mentioned as below:他们提出了另一种我喜欢并实施的方法,如下所述:
Pass the key: value pair as a JSON string and parse it appropriately in the lambda function.将 key: value 对作为 JSON 字符串传递,并在 lambda function 中对其进行适当解析。
Environment:
Variables:
Env1: '{"REGION": "REGION_VALUE", "ENDPOINT": "http://SOME_ENDPOINT"}'
This suggestion has a little overhead on programming to parse the JSON string, but at this moment I will recommend this as solution for above problem.这个建议对解析 JSON 字符串的编程有一点开销,但此时我会推荐这个作为上述问题的解决方案。
I achieved this with the PyPlate macro.我通过 PyPlate 宏实现了这一点。 Take environment variables list in a commalimited以逗号分隔的环境变量列表
Parameters:
EnvVars:
Type: CommaDelimitedList
Description: Comma separated list of Env vars key=value pairs (key1=value1,key2=value2)
and use it in the Lambda Resource:并在 Lambda 资源中使用它:
Environment:
Variables: |
#!PyPlate
output = dict()
for envVar in params['EnvVars']:
key, value = envVar.split('=')
output.update({key: value})
You can try to orchestrate creation of specific resources using AWS::NoValue您可以尝试使用 AWS::NoValue 来编排特定资源的创建
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/pseudo-parameter-reference.html https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/pseudo-parameter-reference.html
Below is taken from variables creation for LambdaFunction以下摘自 LambdaFunction 的变量创建
Conditions:
IsProd: !Equals [!Ref Env, "production"]
Environment:
Variables:
USER: !If [IsProd, !GetAtt ...., Ref: AWS::NoValue]
This is the right way to use global variables.这是使用全局变量的正确方法。
Globals:
Function:
Timeout: 60
Runtime: nodejs10.x
Environment:
Variables:
STAGE: !Ref Stage
DatabaseName: !Ref DatabaseName
DatabaseUsername: !Ref DatabaseUsername
DatabasePassword: !Ref DatabasePassword
DatabaseHostname: !Ref DatabaseHostname
AuthyAPIKey: !Ref AuthyApiKey
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