Provisioning Lambda Concurrency

main.tf

esource "aws_cloudwatch_log_group" "entropy-engine-lambda" {
  name              = "/aws/lambda/${aws_lambda_function.entropy-engine-lambda.function_name}" 
  retention_in_days = local.log-retention
  tags = {
    branch  = terraform.workspace
    project = var.project
  }
}


resource "aws_lambda_function" "entropy-engine-lambda" {
  depends_on       = [aws_s3_bucket_object.entropy-engine-object] 									
  s3_bucket        = "ec-api-lambda-deploys"
  s3_key           = "${terraform.workspace}/${var.project}/entropy-engine.jar"						
  function_name    = "${terraform.workspace}-${var.project}-entropy-engine"                        	
  role             = data.aws_iam_role.role_for_lambda.arn                                        	
  handler          = "edu.harvard.api.lambdas.URandom"                              		
  source_code_hash = filebase64sha256("../entropy-engine/target/entropy-engine-0.0.1-SNAPSHOT.jar") 	
  runtime          = "java11"
  publish 		   = true																			// This is need only when we are have aws_lambda_provisioned_concurrency_config
  timeout          = 30
  memory_size      = 768
  vpc_config {
    subnet_ids         = data.aws_subnet_ids.lambda_subnets.ids
    security_group_ids = data.aws_security_groups.lambda_security_groups.ids
  }
  environment {
    variables = {
      JDBC_URL_SECRET    = local.jdbc_secret
      MEMCACHED_HOSTNAME = data.aws_elasticache_cluster.memcache_cluster.cluster_address
      MEMCACHED_PORT     = data.aws_elasticache_cluster.memcache_cluster.port
      LOG_LEVEL          = local.loglevel
      TTL_SECS           = "60"

      MEMCACHE_HOSTNAME = data.aws_elasticache_cluster.memcache_cluster.cluster_address
      MEMCACHE_PORT     = data.aws_elasticache_cluster.memcache_cluster.port
    }
  }
  tags = {
    branch  = terraform.workspace
    project = var.project
  }
}

resource "aws_lambda_provisioned_concurrency_config" "entropy-engine-concurrency" {
  function_name                     = aws_lambda_function.entropy-engine-lambda.function_name
  provisioned_concurrent_executions = 10
  qualifier                         = aws_lambda_function.entropy-engine-lambda.version
}


// Permission for API to invoke Lambda
resource "aws_lambda_permission" "allow-entropy-engine-lambda" {
  statement_id  = "AllowExecutionFromAPIGateway"
  action        = "lambda:InvokeFunction"
  function_name = aws_lambda_function.entropy-engine-lambda.function_name // should match aws_lambda_function resource name defined above
  principal     = "apigateway.amazonaws.com"
  source_arn    = "${aws_api_gateway_rest_api.gateway.execution_arn}/*/*/*"
}esource "aws_cloudwatch_log_group" "entropy-engine-lambda" {
  name              = "/aws/lambda/${aws_lambda_function.entropy-engine-lambda.function_name}" 
  retention_in_days = local.log-retention
  tags = {
    branch  = terraform.workspace
    project = var.project
  }
}


resource "aws_lambda_function" "entropy-engine-lambda" {
  depends_on       = [aws_s3_bucket_object.entropy-engine-object] 									
  s3_bucket        = "ec-api-lambda-deploys"
  s3_key           = "${terraform.workspace}/${var.project}/entropy-engine.jar"						
  function_name    = "${terraform.workspace}-${var.project}-entropy-engine"                        	
  role             = data.aws_iam_role.role_for_lambda.arn                                        	
  handler          = "edu.harvard.api.lambdas.URandom"                              		
  source_code_hash = filebase64sha256("../entropy-engine/target/entropy-engine-0.0.1-SNAPSHOT.jar") 	
  runtime          = "java11"
  publish 		     = true																		
  timeout          = 30
  memory_size      = 768
  vpc_config {
    subnet_ids         = data.aws_subnet_ids.lambda_subnets.ids
    security_group_ids = data.aws_security_groups.lambda_security_groups.ids
  }
  environment {
    variables = {
      JDBC_URL_SECRET    = local.jdbc_secret
      MEMCACHED_HOSTNAME = data.aws_elasticache_cluster.memcache_cluster.cluster_address
      MEMCACHED_PORT     = data.aws_elasticache_cluster.memcache_cluster.port
      LOG_LEVEL          = local.loglevel
      TTL_SECS           = "60"

      MEMCACHE_HOSTNAME = data.aws_elasticache_cluster.memcache_cluster.cluster_address
      MEMCACHE_PORT     = data.aws_elasticache_cluster.memcache_cluster.port
    }
  }
  tags = {
    branch  = terraform.workspace
    project = var.project
  }
}

// Very dangerous bug - do not use aliases!!!
resource "aws_lambda_provisioned_concurrency_config" "entropy-engine-concurrency" {
  function_name                     = aws_lambda_function.entropy-engine-lambda.function_name
  provisioned_concurrent_executions = 10
  qualifier                         = aws_lambda_function.entropy-engine-lambda.version
}

resource "aws_lambda_permission" "allow-entropy-engine-lambda" {
  statement_id  = "AllowExecutionFromAPIGateway"
  action        = "lambda:InvokeFunction"
  function_name = aws_lambda_function.entropy-engine-lambda.function_name 
  principal     = "apigateway.amazonaws.com"
  source_arn    = "${aws_api_gateway_rest_api.gateway.execution_arn}/*/*/*"
}