title: Docker push to AWS ECR private repo failing with malformed JSON
body: <p>I am trying out AWS ECR and pushing a new tag to our private repossitory.</p>
  
  <p>it goes like this:</p>
  
  <pre><code>export DOCKER_REGISTRY=0123123123123.dkr.ecr.us-east-1.amazonaws.com
  export TAG=0.1
  docker build -t vendor/app-name .
  `aws ecr get-login --region us-east-1`" # generates docker login
  docker tag vendor/app-name $DOCKER_REGISTRY/vendor/app-name:$TAG
  docker push $DOCKER_REGISTRY/vendor/app-name:$TAG
  </code></pre>
  
  <p>Login works, the tag is created and I see it with <code>docker images</code>, but the push fails cryptically.</p>
  
  <pre><code>The push refers to a repository [0123123123123.dkr.ecr.us-east-1.amazonaws.com/vendor/app-name] (len: 2)
  b1a1d76b9e52: Pushing [==================================================&gt;]     32 B/32 B
  Error parsing HTTP response: unexpected end of JSON input: ""
  </code></pre>
  
  <p>It very well might be a misconfiguration, but I can't figure out how to get more output out of it. The command has no debug level options, there are no other logs and I can't intercept network traffic since it seems encrypted.</p>