docker_registry.py

import base64
import os

from charmhelpers.core import hookenv
from charmhelpers.contrib.hahelpers.cluster import peer_ips
from charms.reactive import (
    endpoint_from_flag,
    set_flag,
    clear_flag,
    is_flag_set,
    when,
    when_any,
    when_not,
)
from charms import layer
from charms.leadership import leader_set
from charms.reactive.helpers import data_changed


@when('docker.ready',
      'apt.installed.apache2-utils')
@when_not('charm.docker-registry.configured')
def start():
    layer.status.maint('Configuring the registry.')

    layer.docker_registry.configure_registry()
    layer.docker_registry.start_registry()

    set_flag('charm.docker-registry.configured')
    report_status()


@when('charm.docker-registry.configured')
def report_status():
    '''Update status based on related charms/config.'''
    app_suffix = []
    charm_config = hookenv.config()
    name = charm_config.get('registry-name')
    local_addr = '{}:{}'.format(hookenv.unit_private_ip(),
                                charm_config.get('registry-port'))

    if layer.docker_registry.is_container(name, all=False):
        if is_flag_set('charm.docker-registry.tls-enabled'):
            app_suffix.append('https')
        else:
            app_suffix.append('http')
        if is_flag_set('website.available'):
            app_suffix.append('proxied')

        status_suffix = ' ({})'.format(', '.join(app_suffix))
        layer.status.active('Ready at {}{}.'.format(local_addr, status_suffix))
    else:
        layer.status.blocked('{} container is stopped.'.format(name))


@when('charm.docker-registry.configured')
@when_any('config.changed',
          'leadership.changed.http-secret')
def config_changed():
    layer.status.maint('Reconfiguring the registry.')
    charm_config = hookenv.config()
    name = charm_config.get('registry-name')

    # If a provider gave us certs and http-host changed, make sure SANs are accurate
    if is_flag_set('cert-provider.certs.available') and charm_config.changed('http-host'):
        request_certificates()

    # If our name changed, make sure we stop the old one
    if charm_config.changed('registry-name') and charm_config.previous('registry-name'):
        name = charm_config.previous('registry-name')

    layer.docker_registry.stop_registry(name=name)
    layer.docker_registry.configure_registry()
    layer.docker_registry.start_registry()

    # Now that we reconfigured the registry, inform connected clients if
    # anything changed that they should know about.
    if (is_flag_set('charm.docker-registry.client-configured') and
            any((charm_config.changed('auth-basic-password'),
                 charm_config.changed('auth-basic-user'),
                 charm_config.changed('http-host')))):
        configure_client()

    report_status()


@when('charm.docker-registry.configured',
      'endpoint.docker-registry.joined')
@when_not('charm.docker-registry.client-configured')
def configure_client():
    '''Set all the registry config that clients may care about.'''
    registry = endpoint_from_flag('endpoint.docker-registry.joined')
    charm_config = hookenv.config()
    data = {}

    # auth config
    basic_password = charm_config.get('auth-basic-password')
    basic_user = charm_config.get('auth-basic-user')
    if basic_user and basic_password:
        # basic auth needs all or nothing
        data['basic_user'] = basic_user
        data['basic_password'] = basic_password
    else:
        data['basic_user'] = None
        data['basic_password'] = None

    # tls config
    if is_flag_set('charm.docker-registry.tls-enabled'):
        url_prefix = 'https'
        cert_provider = endpoint_from_flag('cert-provider.ca.available')
        if cert_provider:
            tls_ca = cert_provider.root_ca_cert
            data['tls_ca'] = tls_ca
    else:
        url_prefix = 'http'
        data['tls_ca'] = None

    # http config
    http_config = charm_config.get('http_config')
    netloc = layer.docker_registry.get_netloc()
    if http_config:
        # When set, trust that the user knows best
        data['registry_url'] = http_config
    else:
        data['registry_url'] = '{}://{}'.format(url_prefix, netloc)

    # send config
    hookenv.log('Sending {} config to client: {}.'.format(netloc, data))
    registry.set_registry_config(netloc, **data)
    set_flag('charm.docker-registry.client-configured')


@when('charm.docker-registry.configured',
      'charm.docker-registry.client-configured')
@when('endpoint.docker-registry.requests-pending')
def process_client_image_request():
    '''Handle a client request to host an image in the registry.'''
    hookenv.log('TODO: allow clients to request registry image')
    registry = endpoint_from_flag('endpoint.docker-registry.requests-pending')
    registry.mark_completed()


@when('cert-provider.available')
@when_not('cert-provider.certs.available')
def request_certificates():
    '''Request new certificate data.'''
    cert_provider = endpoint_from_flag('cert-provider.available')

    # Set the private ip of this unit as the Common Name for the cert.
    # NB: Any 'http-host' config will be added to the SANs list; we
    # want to ensure we always have a consistent CN regardless of config.
    cert_cn = hookenv.unit_private_ip()

    # Create a path safe name by removing path characters from the unit name.
    cert_name = hookenv.local_unit().replace('/', '_')

    # gather up all the alt names we want for our cert
    proxy_ep = endpoint_from_flag('proxy.available')
    sans = layer.docker_registry.get_tls_sans(proxy_ep.relation if proxy_ep else None)

    # if our alt names have changed, request a new cert
    if data_changed('tls_sans', sans):
        hookenv.log('Requesting new cert for CN: {} with SANs: {})'.format(cert_cn, sans))
        cert_provider.request_server_cert(cert_cn, sans, cert_name)
    else:
        hookenv.log('Not requesting new tls data; SANs did not change: {}'.format(sans))


@when('charm.docker-registry.configured')
@when('cert-provider.server.certs.changed')
def write_certs():
    '''Write cert data to our configured location.'''
    cert_provider = endpoint_from_flag('cert-provider.server.certs.changed')
    cert_cn = hookenv.unit_private_ip()
    ca = cert_provider.root_ca_cert
    cert = cert_provider.server_certs_map[cert_cn]

    # configure when we have everything we need
    if not (cert and ca and cert.cert and cert.key):
        layer.status.maint('Incomplete TLS data. Retrying.')
        clear_flag('charm.docker-registry.tls-enabled')
    else:
        layer.status.maint('Reconfiguring registry with TLS.')

        # Only configure/restart if cert data was written.
        if layer.docker_registry.write_tls(ca, cert.cert, cert.key):
            # NB: set the tls flag prior to calling configure
            set_flag('charm.docker-registry.tls-enabled')

            layer.docker_registry.stop_registry()
            layer.docker_registry.configure_registry()
            layer.docker_registry.start_registry()

            # If we have clients, let them know our tls data has changed
            if (is_flag_set('charm.docker-registry.client-configured')):
                configure_client()

            clear_flag('cert-provider.server.certs.changed')
            report_status()
        else:
            layer.status.maint('Could not write TLS data. Retrying.')
            clear_flag('charm.docker-registry.tls-enabled')


@when('charm.docker-registry.configured')
@when('charm.docker-registry.tls-enabled')
@when_not('cert-provider.available')
def remove_certs():
    '''Remove cert data from our configured paths when a tls provider is gone.'''
    # Remove cert data prior to reconfiguring/starting.
    layer.docker_registry.stop_registry()
    layer.docker_registry.remove_tls()

    # NB: remove the tls flag prior to calling configure
    clear_flag('charm.docker-registry.tls-enabled')
    layer.docker_registry.configure_registry()
    layer.docker_registry.start_registry()

    # If we have clients, let them know our tls data has changed
    if (is_flag_set('charm.docker-registry.client-configured')):
        configure_client()
    report_status()


@when('charm.docker-registry.configured')
@when('leadership.is_leader')
@when('website.available')
def update_reverseproxy_config():
    '''Configure a reverse proxy.

    The lead unit is responsible for setting appropriate proxy config for all
    known registry peers. The oldest known peer will be configured as the
    primary proxied server. Other peers will be configured as backup servers
    which can take over if the primary fails.
    '''
    website = endpoint_from_flag('website.available')
    port = hookenv.config().get('registry-port')

    # Gather data about our peers, including ourself
    peers = peer_ips(peer_relation="peer")
    peers[hookenv.local_unit()] = hookenv.unit_private_ip()

    # Construct a list of server stanzas
    # NB: use oldest peer (the first unit name in our sorted peers list)
    # versus juju leadership to determine primary vs backup servers:
    #  https://bugs.launchpad.net/layer-docker-registry/+bug/1815459
    common_opts = "check inter 2000 rise 2 fall 5 maxconn 4096"
    is_primary = True
    servers = []
    for unit in sorted(peers):
        if is_primary:
            server_opts = common_opts
            is_primary = False
        else:
            server_opts = common_opts + ' backup'
        servers.append('   - [{name}, {ip}, {port}, {opts}]'.format(
            name=unit.replace('/', '-'),
            ip=peers[unit],
            port=port,
            opts=server_opts))

    services_yaml = """
- service_name: %(app)s
  service_host: 0.0.0.0
  service_port: %(port)s
  service_options:
   - mode http
   - balance leastconn
   - option httpchk GET / HTTP/1.0
  servers:
%(servers)s
""" % {
        'app': hookenv.application_name(),
        'port': port,
        'servers': "\n".join(servers),
    }
    # Send yaml to the proxy on initial relation and when it changes.
    if data_changed('proxy_stanza', services_yaml):
        # NB: interface needs configure() to set ip/host/port data and
        # set_remote for the blob of services.
        website.configure(port=port)
        website.set_remote(services=services_yaml)

    # A proxy may change our netloc; if we have clients, tell them.
    netloc = layer.docker_registry.get_netloc()
    if (is_flag_set('charm.docker-registry.client-configured') and
            data_changed('proxy_netloc', netloc)):
        configure_client()

    # Early versions of this charm incorrectly set an 'all_services'
    # key on the website relation. Kill it.
    if not is_flag_set('charm.docker-registry.proxy-data.validated'):
        website.set_remote(all_services=None)
        set_flag('charm.docker-registry.proxy-data.validated')

    # Ensure we'll validate website relation data from a follower perspective
    # if we ever lose leadership.
    clear_flag('charm.docker-registry.proxy-follower.validated')


@when('charm.docker-registry.configured')
@when('website.available')
@when_not('leadership.is_leader')
@when_not('charm.docker-registry.proxy-follower.validated')
def validate_follower_reverseproxy():
    '''Remove invalid reverseproxy config for non-leader units.'''
    # Early versions of this charm (rev 80ish) incorrectly set website config
    # for follower units. Clean that up.
    website = endpoint_from_flag('website.available')
    website.set_remote(all_services=None, hostname=None, port=None)
    set_flag('charm.docker-registry.proxy-follower.validated')


@when('charm.docker-registry.configured')
@when('leadership.is_leader')
@when('endpoint.website.departed')
def remove_reverseproxy_config():
    '''Remove reverse proxy config.

    The lead unit is responsible for setting appropriate proxy config. When
    the proxy relation is removed, manage cached proxy data and client config.
    '''
    # Clear cache so a subsequent join will send config to the new proxy
    data_changed('proxy_stanza', None)

    # Losing a proxy may change our netloc; if we have clients, tell them.
    netloc = layer.docker_registry.get_netloc()
    if (is_flag_set('charm.docker-registry.client-configured') and
            data_changed('proxy_netloc', netloc)):
        configure_client()

    clear_flag('endpoint.website.departed')


@when('charm.docker-registry.configured')
@when('nrpe-external-master.available')
def setup_nagios():
    '''Update the NRPE configuration for the given service.'''
    hookenv.log("updating NRPE checks")
    nagios = endpoint_from_flag('nrpe-external-master.available')
    charm_config = hookenv.config()

    check_args = {}
    if charm_config.get('nagios_context'):
        check_args['context'] = charm_config['nagios_context']
    if charm_config.get('nagios_servicegroups'):
        check_args['servicegroups'] = charm_config['nagios_servicegroups']
    nagios.add_check(['/usr/lib/nagios/plugins/check_http',
                      '-I', '127.0.0.1', '-p', str(charm_config.get('registry-port')),
                      '-e', " 200 OK", '-u', '/'],
                     name="check_http",
                     description="Verify docker-registry is responding",
                     **check_args)
    nagios.added()


@when('nrpe-external-master.removed')
def remove_nrpe_external():
    nagios = endpoint_from_flag('nrpe-external-master.removed')
    nagios.removed()


@when('leadership.is_leader')
@when_not('leadership.set.http-secret')
def generate_http_secret():
    leader_set({'http-secret': base64.b64encode(os.urandom(32)).decode('utf-8')})