feat: Add project files

.gitignore

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+### Terraform template
+# Local .terraform directories
+**/.terraform/*
+
+# .tfstate files
+*.tfstate
+*.tfstate.*
+
+# Crash log files
+crash.log
+
+# Exclude all .tfvars files, which are likely to contain sentitive data, such as
+# password, private keys, and other secrets. These should not be part of version
+# control as they are data points which are potentially sensitive and subject
+# to change depending on the environment.
+#
+*.tfvars
+
+# Ignore override files as they are usually used to override resources locally and so
+# are not checked in
+override.tf
+override.tf.json
+*_override.tf
+*_override.tf.json
+
+# Include override files you do wish to add to version control using negated pattern
+#
+# !example_override.tf
+
+# Include tfplan files to ignore the plan output of command: terraform plan -out=tfplan
+# example: *tfplan*
+
+# Ignore CLI configuration files
+.terraformrc
+terraform.rc
+
+.idea
+backend/lambda.zip

backend.tf

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+locals {
+  users_raw = jsondecode(file("${path.root}/users.json"))
+  # change users list to a map of users suitable for Terraform for_each
+  users_map = { for u in local.users_raw : u["id"] => {
+    name    = u["name"]
+    address = u["address"]
+  } }
+}
+
+# Package the lambda in a zip file
+data "archive_file" "lambda_package" {
+  output_path = "${var.lambda_directory}/lambda.zip"
+  source_file = "${var.lambda_directory}/main.py"
+  type        = "zip"
+}
+
+resource "aws_iam_role" "lambda_role" {
+  name               = "${var.prefix}-api-backend"
+  description        = "IAM Role for the API Backend"
+  assume_role_policy = data.aws_iam_policy_document.lambda_role_policy.json
+}
+
+data "aws_iam_policy_document" "lambda_role_policy" {
+  statement {
+    actions = ["sts:AssumeRole"]
+
+    principals {
+      type        = "Service"
+      identifiers = ["lambda.amazonaws.com"]
+    }
+  }
+}
+
+resource "aws_iam_role_policy" "lambda_dynamodb_access" {
+  name   = "dynamodb-access"
+  policy = data.aws_iam_policy_document.lambda_dynamodb_access.json
+  role   = aws_iam_role.lambda_role.id
+}
+
+data "aws_iam_policy_document" "lambda_dynamodb_access" {
+  statement {
+    sid       = "AllowAccessToDynamoDB"
+    actions   = ["dynamodb:Scan"]
+    resources = [aws_dynamodb_table.users.arn]
+  }
+}
+
+
+resource "aws_iam_role_policy_attachment" "lambda_cloudwatch_access" {
+  policy_arn = "arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
+  role       = aws_iam_role.lambda_role.id
+}
+
+resource "aws_iam_role_policy_attachment" "lambda_xray_access" {
+  policy_arn = "arn:aws:iam::aws:policy/AWSXRayDaemonWriteAccess"
+  role       = aws_iam_role.lambda_role.id
+}
+
+
+resource "aws_lambda_function" "api_backend" {
+  function_name    = "${var.prefix}-api-backend"
+  description      = "API Backend for the DevOps challenge project"
+  role             = aws_iam_role.lambda_role.arn
+  handler          = "main.handler"
+  runtime          = "python3.8"
+  timeout          = 29
+  filename         = data.archive_file.lambda_package.output_path
+  source_code_hash = filebase64sha256(data.archive_file.lambda_package.output_path)
+
+  tracing_config {
+    mode = "Active"
+  }
+
+  environment {
+    variables = {
+      DYNAMODB_TABLE = aws_dynamodb_table.users.name
+    }
+  }
+}
+
+resource "aws_cloudwatch_log_group" "log_group" {
+  name              = "/aws/lambda/${aws_lambda_function.api_backend.function_name}"
+  retention_in_days = 14
+}
+
+resource "aws_dynamodb_table" "users" {
+  name           = "${var.prefix}-users"
+  billing_mode   = "PROVISIONED"
+  hash_key       = "id"
+  read_capacity  = 3
+  write_capacity = 3
+
+
+  attribute {
+    name = "id"
+    type = "S"
+  }
+}
+
+resource "aws_dynamodb_table_item" "users" {
+  for_each   = local.users_map
+  table_name = aws_dynamodb_table.users.name
+  hash_key   = aws_dynamodb_table.users.hash_key
+  range_key  = aws_dynamodb_table.users.range_key
+
+  item = <<ITEM
+{
+"id": {"S": "${each.key}"},
+"name": {"S": "${each.value["name"]}"},
+"address": {"S": "${each.value["address"]}"}
+}
+
+ITEM
+}
+
+resource "aws_apigatewayv2_api" "http_api" {
+  name          = "${var.prefix}-http-api"
+  description   = "A simple HTTP API for the devops challenge"
+  protocol_type = "HTTP"
+
+  cors_configuration {
+    allow_origins = ["*"]
+    allow_methods = ["GET", "HEAD"]
+  }
+}
+
+resource "aws_lambda_permission" "allow_apigateway_to_invoke_lambda" {
+  action        = "lambda:InvokeFunction"
+  function_name = aws_lambda_function.api_backend.function_name
+  principal     = "apigateway.amazonaws.com"
+  source_arn    = "${aws_apigatewayv2_api.http_api.execution_arn}/*"
+}
+
+resource "aws_apigatewayv2_integration" "lambda_integration" {
+  api_id               = aws_apigatewayv2_api.http_api.id
+  integration_type     = "AWS_PROXY"
+  integration_method   = "POST"
+  integration_uri      = aws_lambda_function.api_backend.invoke_arn
+  passthrough_behavior = "WHEN_NO_MATCH"
+}
+
+resource "aws_apigatewayv2_stage" "default_stage" {
+  api_id      = aws_apigatewayv2_api.http_api.id
+  auto_deploy = true
+  name        = "$default"
+}
+
+resource "aws_apigatewayv2_route" "users" {
+  api_id    = aws_apigatewayv2_api.http_api.id
+  route_key = "GET /users"
+  target    = "integrations/${aws_apigatewayv2_integration.lambda_integration.id}"
+}

backend/README.md

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+# Backend Lambda function
+
+A lambda scanning a return the content of a dynamodb table. It used as an integration target for an HTTP API.
+
+**Note: It is NOT a best practice to scan all the content of dynamodb table. You should consider adding some index or
+use another database if you need to such kind of access to your data.**
+
+## Requirements
+
+- An environment variable `DYNAMODB_TABLE` containing the name of the dynamodb table
+- An IAM role granting `dynamodb:Scan` to this table

backend/main.py

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+import json
+import logging
+import os
+from typing import List, Dict
+
+import boto3
+
+# Init these resources here to take advantage of lambda context re-utilization.
+dynamodb = boto3.resource("dynamodb")
+table = dynamodb.Table(os.environ["DYNAMODB_TABLE"])
+
+logger = logging.getLogger(__name__)
+logger.setLevel(logging.DEBUG)
+
+
+def get_users(db_table) -> List[Dict]:
+    """
+    Get all users
+    Note: It is NOT a best practice to scan all the content of dynamodb table. You should consider adding some index
+    or use another database if you need to such kind of access to your data.
+    :param db_table:
+    :return:
+    """
+    scan = db_table.scan()  # Bad practice
+    return [item for item in scan["Items"]]
+
+
+def handler(event, context):
+    logger.debug(event)
+    users = json.dumps(get_users(table))
+    logger.info(f"{len(users)} user(s) retrieved.")
+
+    return {
+        "statusCode": "200",
+        'headers': {
+            'Content-Type': 'application/json',
+        },
+        "body": users
+    }
+
+
+# For testing purpose
+if __name__ == '__main__':
+    print(handler({}, None))