AWS Lambda – I – Web Development

Policy:

A policy defines the AWS permissions that you can assign to a user, gourp, or role.
You can create and edit a policy in the visual editor and using JSON (AWS policy Generator)

Ex : Admin -> EC2 Permission (start,stop or Create, terminate.. or allow/deny whatever permission )

Particular Role policy is called inline policy

Roles :

A Role based on attached policy

	- Trusted between AWS Services
	- Assumed between AWS Account Users
	- Web identity, SAML

IAM Role has no associated credentials
Max 1000 Roles Create – Soft Limit

IAM roles are a secure way to grant permissions to entities that you trust. Examples of entities include the following:

IAM user in another account
Application code running on an EC2 instance that needs to perform actions on AWS resources
An AWS service that needs to act on resources in your account to provide its features
IAM roles issue keys that are valid for short durations, making them a more secure way to grant access.

Processes involved

The following are the processes involved in working with AWS lambda and API Gateway −

 1. Create IAM role for permission
 2. Create AWS lambda function
 3. Create API Gateway
 4. Link lambda function to api gateway
 5. Passing data to api gateway

Create User :

  Go to IAM
  Add User
  Create UserName
  Set Permission (Copy existing or Attach existing policies)
  we get Access Key & Secret access key

AWS CLI Configuration in Windows

1 : Install Python
2 : Install AWS CLI from download and install page for windows vesion
3 : Check AWS CLI vesion “aws –version”
4 : Copy the Role arn
5 : Crate a index.js file and zip the file as well note the file path
6 : Create a command with follwing properties within a single line without enter key

aws lambda create-function 
			--function-name "***" 
			--runtime "nodejs12.x" 
			--role "arn:aws:iam::***/***" 
			--handler "***.handler" 
			--timeout *** 
			--memory-size *** 
			--zip-file "fileb://***"

7 : Example –

aws lambda create-function 
			--function-name "awsCliLambdaFunction" 
			--runtime "nodejs12.x" 
			--role "arn:aws:iam::00000:role/aws-cli-lambda" 
			--handler "index.handler" 
			--timeout 5 
			--memory-size 256 
			--zip-file "fileb://E:/Prabha/Local/AWS/index.zip"

8 : Go to command prompt and run command : aws configure
9 : Give the values as shown below –

AWS Access Key ID [****************I4BY]: ******
		AWS Secret Access Key [****************R+0n]: *****
		Default region name [None]: ap-south-1
		Default output format [None]: json

10 : Run the below command –

C:\Users\Admin>aws lambda create-function --function-name "awsCliLambdaFunction" --runtime "nodejs12.x" --role "arn:aws:iam::000000:role/aws-cli-lambda" --handler "index.handler" --timeout 5 --memory-size 256 --zip-file "fileb://E:/Prabha/Local/AWS/index.zip"
		{
			"LastUpdateStatus": "Successful",
			"FunctionName": "awsCliLambdaFunction",
			"LastModified": "2020-12-23T10:36:15.098+0000",
			"RevisionId": "****",
			"MemorySize": 256,
			"State": "Active",
			"Version": "$LATEST",
			"Role": "arn:aws:iam::****:role/aws-cli-lambda",
			"Timeout": 5,
			"Handler": "index.handler",
			"Runtime": "nodejs12.x",
			"TracingConfig": {
				"Mode": "PassThrough"
			},
			"CodeSha256": "****",
			"Description": "",
			"CodeSize": 231,
			"FunctionArn": "arn:aws:lambda:ap-south-1:00000:function:awsCliLambdaFunction",
			"PackageType": "Zip"
		}

C:\Users\Admin>python -v
ERROR : Python was not found; run without arguments to install from the Microsoft Store, or disable this shortcut from Settings > Manage App Execution Aliases.

Solution : Uninstall old Python versions and install new , please note the Python installation path, sometimes it choose Admin/Data/Local/ path

After successfully executed the function in lambda, we can not see the log in cloudWatch, it throws error warning as :

ERROR 2 :
“Log group does not exist
The specific log group: /aws/lambda/awsCliLambdaFunction does not exist in this account or region.”

It says that log group does not exist : The specified log group does not exist.
Solution : ?

Get the Access Key & Secret access key from console top menu select -> My security credentials -> Generate by click the create key button

1. Add user
1. aws configure :
2. Access Key & Secret access key
3. Region name :

Lambda sample applications 1
Lambda sample applications 2
Lambda sample applications 3

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Using AWS Lambda with the AWS Command Line Interface 2
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