mock-proxy

a.k.a. Moxie

Notification: this repository is archived since May 18, 2022. Please find an alternative solution for your mock-proxy needs

mock-proxy (a.k.a Moxie—short for mo(ck)(pro)xy) is a replacement proxy relying on the HTTP intercept capabilities of ICAP, as implemented in go-icap/icap. This replacement proxy is intended for writing integration tests that mock responses from external services at the network level. In order to use mock-proxy, a test environment specifies it as an HTTP proxy using http_proxy type environment variables (or however proxies are configured in your scenario). Because it works at the network level and can be used by many services at once using proxy config, it works well in microservices environments where many services need to mock the same 3rd party dependencies.

In short, ICAP allows us to specify a set of criteria to match all requests against and then route them accordingly. When a request hits the proxy, if it matches this criteria then a semi-hardcoded response is automatically short circuited in. If it does not match the criteria, the request proceeds as normal.

Features

• Selectively mock endpoints, allowing some requests to hit the internet, and others to be faked locally.
• Configure mocked routes using an HCL2 based Routes file.
• Dynamic URL support, allowing mocking traditional RESTful APIs easily.
• Templated responses using "Transformer" interface, including the built in substitution-variables endpoint.
• Mock git clone operations using the git route type.
• Mock HTTPS endpoints using Squid's SSLBump feature.

See documentation and examples for more information.

Disclaimer

This is not an officially supported HashiCorp product.

Documentation

There is documentation of how to use mock-proxy features such as the Routes file in the docs directory.

Examples

See examples of different use cases for mock-proxy

Layout

In general, this project attempts to stick to the layout prescribed in golang-standards/project-layout

build: CircleCI and Docker build scripts. Also includes relevant squid proxy config and setup script.

certs: Self signed certificates used to configure SSL Bump for local development.

cmd: Contains main.go file for building mock-proxy.

deployments: Configs for publishing builds of mock-proxy.

hack: Bash scripts for assorted tasks such as running mock-proxy locally

mocks: Faux endpoints for testing the proxy redirect within this project.

pkg: The main Go code directory which houses the implementation of the custom ICAP server.

Getting started

The local development and demonstration environment for mock-proxy relies on Docker to orchestrate the various services (client, ICAP server, Squid server) required to successfully mock requests. If you do not have a functional Docker environment, see the getting started docs on Docker's website.

To develop locally, run ./hack/local-dev-up.sh to start the proxy and client containers. The result of this script will leave you in a bash shell inside the client container. From here, you can create substitution variables and test API endpoints you've hardcoded via a GET curl.

To keep an eye on the proxy logs, tail the proxy container logs via docker logs -f deployments_proxy_1 (or whatever name your proxy's container happens to have).

Dependency Management

This project uses Go modules without a vendor dir.

This Modules Wiki will probably have better advice about adding / upgrading dependencies than can be stated here.