Docker Registry Authentication Proxy

server.js

var http = require('http'),
    https = require('https'),
    buffer = require('buffer'),
    httpProxy = require('http-proxy');

var tokens = {},
    basicAuth = new Buffer(process.env.BASIC_AUTH).toString('base64');


//
// Create a proxy server with custom application logic
//
var proxy = httpProxy.createProxyServer({ secure: false, changeOrigin: true });

var cacheToken = function(req, rep) {
  var token, tokenParts, signature, repository, access, key;
  if (typeof rep.headers['x-docker-token'] === 'string') {
    // signature=2284514fb61ddc0d9a9f87eada51c36831b3f9b5,repository="xxxx/xxxx",access=read
    token = rep.headers['x-docker-token'];
    tokenParts = token.split(',');
    if(tokenParts.length === 3) {
      signature = tokenParts[0];
      repository = (tokenParts[1].split('"'))[1];
      access = (tokenParts[2].split('"'))[1];
      key = req.headers['host'] + '/' + repository;
      console.log('AUTH ' + token);
      tokens[key] = token;
    }
  }
};

var fetchToken = function(req, res) { 
  var token, key;
}

proxy.on('proxyRes', function (proxyRes, req, res) {
  console.log('INFO: resp='+req.url, JSON.stringify(proxyRes.headers, true, 2));
  cacheToken(req, proxyRes);
  delete proxyRes.headers['x-docker-endpoints'];
  res.setHeader('x-docker-endpoints', process.env.REGISTRY_HOST);
});


proxy.on('proxyReq', function(proxyReq, req, res, options) {

  console.log('INFO: req='+req.url, JSON.stringify(req.headers, true, 2));
  if(req.headers['host'] === process.env.INDEX_HOST) {
    proxyReq.setHeader('Authorization', 'Basic ' + basicAuth);
  }

  if(req.headers['host'] === process.env.REGISTRY_HOST) { 
    var path, repo, key, token;
    path = req.url.split('/');    
    repo = path[3] + '/' + path[4];
    key = req.headers['host'] + '/' + repo;
    if(typeof tokens[key] === 'string') {
      token = tokens[key];
      console.log('Token ' + token);
      proxyReq.setHeader('Authorization', 'Token ' + token);
    } 
  }
});

proxy.on('error', function (error, req, res) {
    var json;
    console.log('ERROR', error);
    if (!res.headersSent) {
        res.writeHead(500, { 'content-type': 'application/json' });
    }

    json = { error: 'proxy_error', reason: error.message };
    res.end(JSON.stringify(json));
});


var server = http.createServer(function(req, res) {
  var endpoint, headers = {};

  if(req.headers['host'] === process.env.INDEX_HOST) {
    endpoint = 'https://' + process.env.INDEX_UPSTREAM;
  } 
  else if(req.headers['host'] === process.env.REGISTRY_HOST) {
    endpoint = 'https://' + process.env.REGISTRY_UPSTREAM;
  }
  else {
    res.writeHead(500, {
      'Content-Type': 'text/plain'
    });
    res.end('Request failed');
    return;
  }

  proxy.web(req, res, {target: endpoint, headers: headers} );

});

console.log("docker registry auth proxy listening on port 80")
server.listen(80);

Corresponding Dockerfile

FROM ubuntu:14.04

ENV REGISTRY_UPSTREAM registry-1.docker.io
ENV REGISTRY_HOST registry.xxxx.local
ENV INDEX_UPSTREAM index.docker.io
ENV INDEX_HOST index.xxxx.local
ENV BASIC_AUTH user:pass

WORKDIR /

RUN apt-get update && \
    apt-get -y install node npm && \
    npm install http-proxy

ADD server.js /server.js

ENTRYPOINT ["/usr/bin/nodejs"]

CMD ["/server.js"]

EXPOSE 80