bigtop-packages/src/charm/kafka/layer-kafka/reactive/kafka.py

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# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
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#
#     http://www.apache.org/licenses/LICENSE-2.0
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from charmhelpers.core import hookenv
from charms.layer.apache_bigtop_base import get_layer_opts, get_package_version
from charms.layer.bigtop_kafka import Kafka
from charms.reactive import set_state, remove_state, when, when_not
from charms.reactive.helpers import data_changed


@when('bigtop.available')
@when_not('zookeeper.joined')
def waiting_for_zookeeper():
    hookenv.status_set('blocked', 'waiting for relation to zookeeper')


@when('bigtop.available', 'zookeeper.joined')
@when_not('kafka.started', 'zookeeper.ready')
def waiting_for_zookeeper_ready(zk):
    hookenv.status_set('waiting', 'waiting for zookeeper to become ready')


@when('bigtop.available', 'zookeeper.ready')
@when_not('kafka.started')
def configure_kafka(zk):
    hookenv.status_set('maintenance', 'setting up kafka')
    data_changed(  # Prime data changed for network interface
        'kafka.network_interface', hookenv.config().get('network_interface'))
    kafka = Kafka()
    zks = zk.zookeepers()
    kafka.configure_kafka(zks)
    kafka.open_ports()
    set_state('kafka.started')
    hookenv.status_set('active', 'ready')
    # set app version string for juju status output
    kafka_version = get_package_version('kafka') or 'unknown'
    hookenv.application_version_set(kafka_version)


@when('kafka.started', 'zookeeper.ready')
def configure_kafka_zookeepers(zk):
    """Configure ready zookeepers and restart kafka if needed.

    As zks come and go, server.properties will be updated. When that file
    changes, restart Kafka and set appropriate status messages.

    This method also handles the restart if our network_interface
    config has changed.

    """
    zks = zk.zookeepers()
    network_interface = hookenv.config().get('network_interface')
    if not data_changed('zookeepers', zks) and not data_changed(
            'kafka.network_interface', network_interface):
        return

    hookenv.log('Checking Zookeeper configuration')
    hookenv.status_set('maintenance', 'updating zookeeper instances')
    kafka = Kafka()
    kafka.configure_kafka(zks, network_interface)
    hookenv.status_set('active', 'ready')


@when('kafka.started')
@when_not('zookeeper.ready')
def stop_kafka_waiting_for_zookeeper_ready():
    hookenv.status_set('maintenance', 'zookeeper not ready, stopping kafka')
    kafka = Kafka()
    kafka.close_ports()
    kafka.stop()
    remove_state('kafka.started')
    hookenv.status_set('waiting', 'waiting for zookeeper to become ready')


@when('client.joined', 'zookeeper.ready')
def serve_client(client, zookeeper):
    kafka_port = get_layer_opts().port('kafka')
    client.send_port(kafka_port)
    client.send_zookeepers(zookeeper.zookeepers())
    hookenv.log('Sent Kafka configuration to client')