generate terraform apigateway resources from oas3.0 json export

api_gw.py

#!/usr/local/bin/python
# this script will export the API gateway config as an Open API 3.0 json blob
# and then create the appropriate terraform resources
import json
from subprocess import run as sp_run
import boto3

profile_name = 'dev'
output_file = 'terraform/regional/api_gw_methods.tf'

client = boto3.Session(profile_name=profile_name, region_name='us-east-1').client('apigateway')

def get_api_id(api_name):
    response = client.get_rest_apis()
    for apigw in response['items']:
        if apigw['name'] == api_name:
            return apigw['id']
    return False

response = client.get_export(
    restApiId=get_api_id('userlink'),
    stageName='v1',
    exportType='oas30',
    parameters={
        'extensions': 'integrations'
    },
    accepts = "application/json"
)

json_data = json.loads(response['body'].read().decode('utf-8').replace('/v1/', '/'))

# this logic finds paths not explicitly defined in the api definition but we still need parent terraform resources created for
all_paths = []
explicit_paths = [path.replace("/", "", 1) for path in json_data["paths"]]
for path in json_data["paths"]:
    path_name = path.replace("/", "_").replace("_","",1)
    split_path = path_name.split("_")
    for i in range(len(split_path)):
        current = "/".join(split_path[:i+1])
        if current not in all_paths: all_paths.append(current)
for path in all_paths:
    if path not in explicit_paths:
        json_data["paths"][f'/{path}'] = {}

# we do this to get the terraform resources grouped together properly
json_data = json.dumps(json_data, sort_keys=True)
json_data = json.loads(json_data)

output = []
for path in json_data["paths"]:
    path_name = path.replace("{", "").replace("}", "").replace("/", "_")
    output.append(f'resource "aws_api_gateway_resource" "{path_name}" {{')
    output.append("rest_api_id = aws_api_gateway_rest_api.userlink.id")
    output.append(
        f'parent_id = aws_api_gateway_resource.{"_".join(path_name.split("_")[:-1])}.id'
        if len(path_name.split("_")[:-1]) > 1
        else "parent_id = aws_api_gateway_resource._stage_version.id"
    )
    output.append(f'path_part = "{path.split("/")[-1]}"')
    output.append("}\n")

    for method in json_data["paths"][path]:
        method_type = (
            "ANY" if method == "x-amazon-apigateway-any-method" else method.upper()
        )
        output.append(f'resource "aws_api_gateway_method" "{path_name}__{method_type}" {{')
        output.append("rest_api_id = aws_api_gateway_rest_api.userlink.id")
        output.append(f"resource_id = aws_api_gateway_resource.{path_name}.id")
        output.append(f'http_method = "{method_type}"')
        output.append(
            "authorization = "
            + (
                '"NONE" #tfsec:ignore:aws-api-gateway-no-public-access'
                if not json_data["paths"][path][method].get("security")
                else '"CUSTOM"\n  authorizer_id = aws_api_gateway_authorizer.auth.id'
            )
        )
        if json_data["paths"][path][method].get("parameters"):
            output.append("\n  request_parameters = {")
            params = []
            for parameters in json_data["paths"][path][method]["parameters"]:
                params.append(
                    f'"method.request.{parameters["in"]}.{parameters["name"]}" = {str(parameters["required"]).lower()}'
                )
            for param in sorted(params):
                output.append(param)
            output.append("  }")
        output.append("}\n")

        if json_data["paths"][path][method].get("x-amazon-apigateway-integration"):
            output.append(
                f'resource "aws_api_gateway_integration" "{path_name}__{method_type}_userlink" {{'
            )
            output.append(f"rest_api_id = aws_api_gateway_rest_api.userlink.id")
            output.append(f"resource_id = aws_api_gateway_resource.{path_name}.id")
            output.append(
                f"  http_method = aws_api_gateway_method.{path_name}__{method_type}.http_method"
            )
            output.append(f'integration_http_method = "POST"')
            output.append(f'type = "AWS_PROXY"')
            output.append(f"uri = local.lambda_invoke_arn")
            output.append("}\n")

        for response in json_data["paths"][path][method]["responses"]:
            output.append(
                f'resource "aws_api_gateway_method_response" "{path_name}__{method_type}__{response}" {{'
            )
            output.append("rest_api_id = aws_api_gateway_rest_api.userlink.id")
            output.append(f"resource_id = aws_api_gateway_resource.{path_name}.id")
            output.append(
                f"http_method = aws_api_gateway_method.{path_name}__{method_type}.http_method"
            )
            output.append(f"status_code = {response}")
            output.append("}\n")

with open(output_file, "w") as outfile:
    for line in output:
        outfile.write(f'{line}\n')

sp_run(["terraform", "fmt", output_file])