Configure Docker Registry to work with Synapse

The generic instructions for setting up the registry's configuration file are here:

https://docs.docker.com/v1.9/registry/configuration/

We need an 'auth' section as documented here:

https://docs.docker.com/v1.9/registry/configuration/#auth

auth:

  token:

    realm: https://repo-prod.prod.sagebase.org/docker/v1/bearerToken

    service: docker.synapse.org

    issuer: www.synapse.org

    rootcertbundle: /etc/docker/registry/cert.pem

where cert.pem contains the certificate found in the stack configuration file, prod-default.properties under

org.sagebionetworks.docker.authorization.certificate

Regarding adding Synapse as a listener, we need a 'notifications' section as documented here:

https://docs.docker.com/v1.9/registry/configuration/#notifications

notifications:

  endpoints:

    - name: Synapse

      disabled: false

      url: https://repo-prod.prod.sagebase.org/dockerRegistryListener/v1/events

      headers: Authentication: Basic: <Base64 encoded user : password>

      timeout: 1m

      threshold: 1m

      backoff: 30s

where the user and password can be found in the stack configuration file, prod-default.properties under

org.sagebionetworks.docker.registry.user.plaintext
org.sagebionetworks.docker.registry.password.plaintext