Maven Routing Proxy

This project is a very simple repository proxy for Maven which routes incoming requests to the correct remote repository based on groupId patterns.

The proxy is intended to be run close to the build environment typically as part of the build process on the CI server. It aims to improve build performance and security by avoiding obsolete network requests for artifacts known to be located on a specific repository. It's a pity that Maven does not support this out of the box.

Quick Setup

1. Install the proxy with npm: sudo npm i maven-routing-proxy -g

2. Configure repositories in config.json.

3. Start the proxy with mvnproxy in the same directory as config.json.

4. Configure Maven to use mirror at http://localhost:8181.

5. Profit!!

Installation

Use NPM to install the proxy:

$ sudo npm i maven-routing-proxy -g

After installation the command mvnproxy should be within PATH.

Configuration

The proxy reads config.json from the work directory (where the proxy is started). The configuration file contains the list of repositories where to look for dependencies with their corresponding groupIds, and also defines the default repository to use.

The following example adds three repositories there the first two are used only when the groupId of the dependency starts with the list of values specified by include. The final, default, is used when none of the previous definitions match the dependency groupId.

{
  "repositories": {
    "https://example.com/nexus/content/repositories/releases": {
      "username": "%NEXUS_USERNAME%",
      "password": "%NEXUS_PASSWORD%",      
      "include": [ "com.example", "org.example" ]	    
    },
    "https://repo.example.net/maven2": {
      "include": [ "net.example" ]
    },
    "default": "https://repo.maven.apache.org/maven2"
  }
}

The first example uses environment variables NEXUS_USERNAME and NEXUS_PASSWORD to configure credentials. At the moment only Basic authentication is supported for authentication but that is sufficient with at least Nexus.

The credentials are optional and the second example does not specify any.

Finally "default" is used to configure the default repository to which the request is directed at in case none of the previous repositories match the dependency groupId. The default repository is optional and does not accept credentials.

Running the Proxy

After the proxy has been configured the proxy can be started:

$ mvnproxy

Make sure that the configuration file config.json is located in the same directory where the proxy is started.

The proxy accepts connections on port 8181. At the moment the port is fixed and cannot be changed through configuration.

Configuring Maven

To start using the proxy you need to configure a mirror in Maven. Mirrors are configured in ~/.m2/settings.xml. Below is a complete example of the configuration file:

<?xml version="1.0" encoding="UTF-8"?>
<settings xmlns="http://maven.apache.org/POM/4.0.0" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
                            http://maven.apache.org/xsd/settings-1.0.0.xsd">
  <mirrors>
    <mirror>
      <url>http://localhost:8181</url>
      <mirrorOf>*</mirrorOf>
    </mirror>
  </mirrors>
</settings>

Full instructions on how to configure mirrors can be found in the Maven documentation.

Running the Proxy with Docker

Docker Hub contains a ready-to-run image which can be configured using environment variables.

Define your repositories with environment variables REPO1_URL, REPO2_URL and so on. Use a comma separated list with REPO1_INCLUDES and REPO2_INCLUDES to configure the groupIds associated with the repository. Username and password can be configured with REPO1_USERNAME and REPO1_PASSWORD. The default repository is Maven Central (ie. https://repo.maven.apache.org/maven2).

If you want to reference additional environment variables within the repository configuration (eg. username and password) you can do that by surrounding the environment variable with percent characters, eg. %NEXUS_USERNAME%. The value is replaced with the value of the corresponding environment variable, eg. NEXUS_USERNAME.

The maximum number of repositories that can be configured with the Docker image is 10. Just modify run.sh if you need more.

Contributions

If you need an enhancement or encounter a bug please create an issue. I'll have a look and try to come up with a solution.

Contributions are also welcome! Please feel free to submit PRs with issues.