new devop til about localstack

DevOps/simulating-aws-lambda-localstack.md

@@ -0,0 +1,161 @@
+# Simulating AWS Lambda locally using LocalStack
+
+## Pre-requisties
+
+1. Install Docker & Start the demon (if not already running).
+2. Install LocalStack according to your system requirements.
+   1. Start the localstack process
+   ```
+   localstack start -d
+   ```
+3. Install [awslocal](https://github.com/localstack/awscli-local) latest version.
+
+
+## Prepare your Lambda Function (Go Example)
+
+### Create a simple Go Lambda Handler
+
+```go
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"github.com/aws/aws-lambda-go/events"
+	"github.com/aws/aws-lambda-go/lambda"
+)
+
+type RequestBody struct {
+	Num1 int `json:"num1"`
+	Num2 int `json:"num2"`
+}
+
+func handler(ctx context.Context, request events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error) {
+	var body RequestBody
+	err := json.Unmarshal([]byte(request.Body), &body)
+	if err != nil {
+		return events.APIGatewayProxyResponse{StatusCode: 400, Body: "Invalid request body"}, nil
+	}
+
+	product := body.Num1 * body.Num2
+	responseBody := fmt.Sprintf("The product of %d and %d is %d", body.Num1, body.Num2, product)
+
+	return events.APIGatewayProxyResponse{
+		StatusCode: 200,
+		Body:       responseBody,
+	}, nil
+}
+
+func main() {
+	lambda.Start(handler)
+}
+```
+
+### Initialize Go project and tidy dependencies.
+
+```
+go mod init localstack-go-lambda-example
+go mod tidy
+```
+
+### Build for Linux amd64.
+
+```
+GOOS=linux GOARCH=amd64 go build -o main main.go
+```
+
+Zip the binary (make sure to name the binary main).
+
+```
+zip main.zip main
+```
+
+
+## Create AWS Lambda
+
+Go 1.x runtime is now unsupported on AWS. Refer documentation when setting up in real environment.
+
+```sh
+awslocal lambda create-function \
+    --function-name localstack-go-lambda-example \
+    --runtime go1.x \
+    --zip-file fileb://main.zip \
+    --handler main \
+    --role arn:aws:iam::000000000000:role/lambda-role
+```
+
+Output Example
+
+```json
+{
+    "FunctionName": "localstack-go-lambda-example",
+    "FunctionArn": "arn:aws:lambda:us-west-1:000000000000:function:localstack-go-lambda-example",
+    "Runtime": "go1.x",
+    "Role": "arn:aws:iam::000000000000:role/lambda-role",
+    "Handler": "main",
+    "CodeSize": 5408451,
+    "Description": "",
+    "Timeout": 3,
+    "MemorySize": 128,
+    "LastModified": "2024-07-23T19:26:58.271251+0000",
+    "CodeSha256": "dY9rW1dQKjY0sS6/ijsx8B1ZtT8iQlO9qhTfCSieX9I=",
+    "Version": "$LATEST",
+    "TracingConfig": {
+        "Mode": "PassThrough"
+    },
+    "RevisionId": "c5969abb-b2bf-4a41-967a-6d043b2f41bd",
+    "State": "Pending",
+    "StateReason": "The function is being created.",
+    "StateReasonCode": "Creating",
+    "PackageType": "Zip",
+    "Architectures": [
+        "x86_64"
+    ],
+    "EphemeralStorage": {
+        "Size": 512
+    },
+    "SnapStart": {
+        "ApplyOn": "None",
+        "OptimizationStatus": "Off"
+    }
+}
+```
+
+## Invoke Lambda
+
+Wait for a 5-10 seconds before invoking the lambda.
+
+> Lambda execution on localstack is synchronus so you will not see live output
+
+```sh
+awslocal lambda invoke --function-name localstack-go-lambda-example \
+    --cli-binary-format raw-in-base64-out \
+    --payload '{"body": "{\"num1\": 10, \"num2\": 10}"}' output.txt
+```
+
+Or use the following command, when sending payload from a file (make sure the file contents are bas64 encoded).
+
+```sh
+awslocal lambda invoke \
+    --function-name localstack-go-lambda-example \
+    --payload file://encoded_payload \
+    response.json
+```
+
+You should see lambda output in output.txt
+
+```json
+{
+    "statusCode": 200,
+    "headers": null,
+    "multiValueHeaders": null,
+    "body": "The product of 10 and 10 is 100"
+}
+```
+
+## Resources
+
+1. https://docs.localstack.cloud/user-guide/aws/lambda/#introduction
+2. https://stackoverflow.com/questions/58133166/error-fork-exec-var-task-main-no-such-file-or-directory-while-executing-aws 

README.md

@@ -36,7 +36,7 @@
 * [Compilers](#compilers) [**`1`**]
 * [Data Warehouse](#data-warehouse) [**`1`**]
 * [Databases](#databases) [**`9`**]
-* [DevOps](#devops) [**`6`**]
+* [DevOps](#devops) [**`7`**]
 * [Distributed Computing](#distributed-computing) [**`2`**]
 * [Flutter](#flutter) [**`3`**]
 * [Git](#git) [**`10`**]
@@ -173,6 +173,7 @@
 <li><a target="_blank" href="https://github.com/Bhupesh-V/til/blob/master/DevOps/docker-multiplatform-build.md">Docker multi-platform build using buildx</a>
 <li><a target="_blank" href="https://github.com/Bhupesh-V/til/blob/master/DevOps/docker-quick-guide.md">Docker 🐋 quick guide</a>
 <li><a target="_blank" href="https://github.com/Bhupesh-V/til/blob/master/DevOps/set-up-sftp-server-using-aws.md">Set up a SFTP server using AWS Transfer Family</a>
+<li><a target="_blank" href="https://github.com/Bhupesh-V/til/blob/master/DevOps/simulating-aws-lambda-localstack.md">Simulating AWS Lambda locally using LocalStack</a>
 </ul>
 
 

SUMMARY.md

@@ -92,6 +92,7 @@
 <li><a href="DevOps/docker-multiplatform-build.md">Docker multi-platform build using buildx</a>
 <li><a href="DevOps/docker-quick-guide.md">Docker 🐋 quick guide</a>
 <li><a href="DevOps/set-up-sftp-server-using-aws.md">Set up a SFTP server using AWS Transfer Family</a>
+<li><a href="DevOps/simulating-aws-lambda-localstack.md">Simulating AWS Lambda locally using LocalStack</a>
 </ul>
 
 ## Distributed Computing

count.json

@@ -1,3 +1,3 @@
 {
- "count": 157
+ "count": 158
 }