api_gateway.tf

# --------------------------------------------------------------
# Step 1 : Create APIGateway
# ---------------------------------------------------------------
resource "aws_api_gateway_rest_api" "apigateway" {
  name = "${data.consul_keys.ck.var.project_name}-${data.consul_keys.ck.var.env}-${var.install_name}-backend"
  description = "Serverless application for SLM"
}

# --------------------------------------------------------------
# Step 2 : Create APIGateway Ressource
# ---------------------------------------------------------------
resource "aws_api_gateway_resource" "proxy_resource" {
  rest_api_id = "${aws_api_gateway_rest_api.apigateway.id}"
  parent_id = "${aws_api_gateway_rest_api.apigateway.root_resource_id}"
  path_part = "{proxy+}"
}

# --------------------------------------------------------------
# Step 3 : Create Method Request
# ---------------------------------------------------------------
resource "aws_api_gateway_method" "proxy_method" {
  rest_api_id = "${aws_api_gateway_rest_api.apigateway.id}"
  resource_id = "${aws_api_gateway_resource.proxy_resource.id}"
  http_method = "ANY"
  authorization = "NONE"
}

# --------------------------------------------------------------
# Step 4 : Activation du CORS (Method Response)
# ---------------------------------------------------------------
resource "aws_api_gateway_method_response" "cors_method_response_200" {
    rest_api_id   = "${aws_api_gateway_rest_api.apigateway.id}"
    resource_id   = "${aws_api_gateway_resource.proxy_resource.id}"
    http_method   = "${aws_api_gateway_method.proxy_method.http_method}"
    status_code   = "200"
    response_models {
        "application/json" = "Empty"
    }
    response_parameters {
        "method.response.header.Access-Control-Allow-Headers" = true,
        "method.response.header.Access-Control-Allow-Methods" = true,
        "method.response.header.Access-Control-Allow-Origin" = true
    }
    depends_on = ["aws_api_gateway_method.proxy_root"]
}


# --------------------------------------------------------------
# Step 5: Route API Gateway Request to Lambda (Create Integration Request)
# ---------------------------------------------------------------
resource "aws_api_gateway_integration" "sendlambda" {
  rest_api_id = "${aws_api_gateway_rest_api.apigateway.id}"
  resource_id = "${aws_api_gateway_method.proxy_method.resource_id}"
  http_method = "${aws_api_gateway_method.proxy_method.http_method}"

  type = "AWS_PROXY"
  integration_http_method = "ANY"
  uri = "${aws_lambda_function.backend_lambda.invoke_arn}"
}

# --------------------------------------------------------------
# Step 6 : Activation du CORS (Integration Response)
# ---------------------------------------------------------------
resource "aws_api_gateway_integration_response" "cors_integ_response" {
    rest_api_id   = "${aws_api_gateway_rest_api.apigateway.id}"
    resource_id   = "${aws_api_gateway_resource.proxy_resource.id}"
    http_method   = "${aws_api_gateway_method.proxy_method.http_method}"
    status_code   = "${aws_api_gateway_method_response.cors_method_response_200.status_code}"
    response_parameters = {
        "method.response.header.Access-Control-Allow-Headers" = "'Content-Type,X-Amz-Date,Authorization,X-Api-Key,X-Amz-Security-Token'",
        "method.response.header.Access-Control-Allow-Methods" = "'GET,OPTIONS,POST,PUT'",
        "method.response.header.Access-Control-Allow-Origin" = "'*'"
    }
}

#----------------------------------------------------------------
# --------------------------------------------------------------
# Step 1-6 For for root path (/)
# ---------------------------------------------------------------
#----------------------------------------------------------------
resource "aws_api_gateway_method" "proxy_root" {
  rest_api_id = "${aws_api_gateway_rest_api.apigateway.id}"
  resource_id = "${aws_api_gateway_rest_api.apigateway.root_resource_id}"
  http_method = "ANY"
  authorization = "NONE"
}

# Enable CORS
resource "aws_api_gateway_method_response" "cors_root_method_200" {
    rest_api_id   = "${aws_api_gateway_rest_api.apigateway.id}"
    resource_id   = "${aws_api_gateway_rest_api.apigateway.root_resource_id}"
    http_method   = "${aws_api_gateway_method.proxy_root.http_method}"
    status_code   = "200"
    response_models {
        "application/json" = "Empty"
    }
    response_parameters {
        "method.response.header.Access-Control-Allow-Headers" = true,
        "method.response.header.Access-Control-Allow-Methods" = true,
        "method.response.header.Access-Control-Allow-Origin" = true
    }
}

resource "aws_api_gateway_integration" "sendlambda_root" {
  rest_api_id = "${aws_api_gateway_rest_api.apigateway.id}"
  resource_id = "${aws_api_gateway_method.proxy_root.resource_id}"
  http_method = "${aws_api_gateway_method.proxy_root.http_method}"

  integration_http_method = "ANY"
  type = "AWS"
  uri = "${aws_lambda_function.backend_lambda.invoke_arn}"

}

# Enable CORS
resource "aws_api_gateway_integration_response" "cors_root_response" {
    rest_api_id   = "${aws_api_gateway_rest_api.apigateway.id}"
    resource_id   = "${aws_api_gateway_rest_api.apigateway.root_resource_id}"
    http_method   = "${aws_api_gateway_method.proxy_method.http_method}"
    status_code   = "${aws_api_gateway_method_response.cors_method_response_200.status_code}"
    response_parameters = {
        "method.response.header.Access-Control-Allow-Headers" = "'Content-Type,X-Amz-Date,Authorization,X-Api-Key,X-Amz-Security-Token'",
        "method.response.header.Access-Control-Allow-Methods" = "'GET,OPTIONS,POST,PUT'",
        "method.response.header.Access-Control-Allow-Origin" = "'*'"
    }
}


# --------------------------------------------------------------
# Step 7 : Deploy and Activate Configuration
# ---------------------------------------------------------------
resource "aws_api_gateway_deployment" "deployApI" {

  depends_on = [
   "aws_api_gateway_integration.sendlambda",
    "aws_api_gateway_integration.sendlambda_root"
  ]
  rest_api_id = "${aws_api_gateway_rest_api.apigateway.id}"
  stage_name = "${data.consul_keys.ck.var.project_name}-${data.consul_keys.ck.var.env}-${var.install_name}-api"
}

# --------------------------------------------------------------
# Step 8 : Allow API Gateway to Access Lambda
# ---------------------------------------------------------------

resource "aws_lambda_permission" "apigw_access" {
  statement_id = "AllowAPIGatewayInvoke"
  action = "lambda:InvokeFunction"
  function_name = "${aws_lambda_function.backend_lambda.arn}"
  principal = "apigateway.amazonaws.com"
  source_arn = "${aws_api_gateway_deployment.deployApI.execution_arn}"

}