adminapi.py

#!/usr/bin/env python
#
# Copyright 2018 Confluent Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

#
# Example Admin clients.
#

from confluent_kafka.admin import AdminClient, NewTopic, NewPartitions, ConfigResource, ConfigSource
from confluent_kafka import KafkaException
import sys
import threading
import logging

logging.basicConfig()


def example_create_topics(a, topics):
    """ Create topics """

    new_topics = [NewTopic(topic, num_partitions=3, replication_factor=1) for topic in topics]
    # Call create_topics to asynchronously create topics, a dict
    # of <topic,future> is returned.
    fs = a.create_topics(new_topics)

    # Wait for operation to finish.
    # Timeouts are preferably controlled by passing request_timeout=15.0
    # to the create_topics() call.
    # All futures will finish at the same time.
    for topic, f in fs.items():
        try:
            f.result()  # The result itself is None
            print("Topic {} created".format(topic))
        except Exception as e:
            print("Failed to create topic {}: {}".format(topic, e))


def example_delete_topics(a, topics):
    """ delete topics """

    # Call delete_topics to asynchronously delete topics, a future is returned.
    # By default this operation on the broker returns immediately while
    # topics are deleted in the background. But here we give it some time (30s)
    # to propagate in the cluster before returning.
    #
    # Returns a dict of <topic,future>.
    fs = a.delete_topics(topics, operation_timeout=30)

    # Wait for operation to finish.
    for topic, f in fs.items():
        try:
            f.result()  # The result itself is None
            print("Topic {} deleted".format(topic))
        except Exception as e:
            print("Failed to delete topic {}: {}".format(topic, e))


def example_create_partitions(a, topics):
    """ create partitions """

    new_parts = [NewPartitions(topic, int(new_total_count)) for
                 topic, new_total_count in zip(topics[0::2], topics[1::2])]

    # Try switching validate_only to True to only validate the operation
    # on the broker but not actually perform it.
    fs = a.create_partitions(new_parts, validate_only=False)

    # Wait for operation to finish.
    for topic, f in fs.items():
        try:
            f.result()  # The result itself is None
            print("Additional partitions created for topic {}".format(topic))
        except Exception as e:
            print("Failed to add partitions to topic {}: {}".format(topic, e))


def print_config(config, depth):
    print('%40s = %-50s  [%s,is:read-only=%r,default=%r,sensitive=%r,synonym=%r,synonyms=%s]' %
          ((' ' * depth) + config.name, config.value, ConfigSource(config.source),
           config.is_read_only, config.is_default,
           config.is_sensitive, config.is_synonym,
           ["%s:%s" % (x.name, ConfigSource(x.source))
            for x in iter(config.synonyms.values())]))


def example_describe_configs(a, args):
    """ describe configs """

    resources = [ConfigResource(restype, resname) for
                 restype, resname in zip(args[0::2], args[1::2])]

    fs = a.describe_configs(resources)

    # Wait for operation to finish.
    for res, f in fs.items():
        try:
            configs = f.result()
            for config in iter(configs.values()):
                print_config(config, 1)

        except KafkaException as e:
            print("Failed to describe {}: {}".format(res, e))
        except Exception:
            raise


def example_alter_configs(a, args):
    """ Alter configs atomically, replacing non-specified
    configuration properties with their default values.
    """

    resources = []
    for restype, resname, configs in zip(args[0::3], args[1::3], args[2::3]):
        resource = ConfigResource(restype, resname)
        resources.append(resource)
        for k, v in [conf.split('=') for conf in configs.split(',')]:
            resource.set_config(k, v)

    fs = a.alter_configs(resources)

    # Wait for operation to finish.
    for res, f in fs.items():
        try:
            f.result()  # empty, but raises exception on failure
            print("{} configuration successfully altered".format(res))
        except Exception:
            raise


def example_delta_alter_configs(a, args):
    """
    The AlterConfigs Kafka API requires all configuration to be passed,
    any left out configuration properties will revert to their default settings.

    This example shows how to just modify the supplied configuration entries
    by first reading the configuration from the broker, updating the supplied
    configuration with the broker configuration (without overwriting), and
    then writing it all back.

    The async nature of futures is also show-cased, which makes this example
    a bit more complex than it needs to be in the synchronous case.
    """

    # Convert supplied config to resources.
    # We can reuse the same resources both for describe_configs and
    # alter_configs.
    resources = []
    for restype, resname, configs in zip(args[0::3], args[1::3], args[2::3]):
        resource = ConfigResource(restype, resname)
        resources.append(resource)
        for k, v in [conf.split('=') for conf in configs.split(',')]:
            resource.set_config(k, v)

    # Set up a locked counter and an Event (for signaling) to track when the
    # second level of futures are done. This is a bit of contrived example
    # due to no other asynchronous mechanism being used, so we'll need
    # to wait on something to signal completion.

    class WaitZero(object):
        def __init__(self, waitcnt):
            self.cnt = waitcnt
            self.lock = threading.Lock()
            self.event = threading.Event()

        def decr(self):
            """ Decrement cnt by 1"""
            with self.lock:
                assert self.cnt > 0
                self.cnt -= 1
            self.event.set()

        def wait(self):
            """ Wait until cnt reaches 0 """
            self.lock.acquire()
            while self.cnt > 0:
                self.lock.release()
                self.event.wait()
                self.event.clear()
                self.lock.acquire()
            self.lock.release()

        def __len__(self):
            with self.lock:
                return self.cnt

    wait_zero = WaitZero(len(resources))

    # Read existing configuration from cluster
    fs = a.describe_configs(resources)

    def delta_alter_configs_done(fut, resource):
        e = fut.exception()
        if e is not None:
            print("Config update for {} failed: {}".format(resource, e))
        else:
            print("Config for {} updated".format(resource))
        wait_zero.decr()

    def delta_alter_configs(resource, remote_config):
        print("Updating {} supplied config entries {} with {} config entries read from cluster".format(
            len(resource), resource, len(remote_config)))
        # Only set configuration that is not default
        for k, entry in [(k, v) for k, v in remote_config.items() if not v.is_default]:
            resource.set_config(k, entry.value, overwrite=False)

        fs = a.alter_configs([resource])
        fs[resource].add_done_callback(lambda fut: delta_alter_configs_done(fut, resource))

    # For each resource's future set up a completion callback
    # that in turn calls alter_configs() on that single resource.
    # This is ineffective since the resources can usually go in
    # one single alter_configs() call, but we're also show-casing
    # the futures here.
    for res, f in fs.items():
        f.add_done_callback(lambda fut, resource=res: delta_alter_configs(resource, fut.result()))

    # Wait for done callbacks to be triggered and operations to complete.
    print("Waiting for {} resource updates to finish".format(len(wait_zero)))
    wait_zero.wait()


def example_list(a, args):
    """ list topics and cluster metadata """

    if len(args) == 0:
        what = "all"
    else:
        what = args[0]

    md = a.list_topics(timeout=10)

    print("Cluster {} metadata (response from broker {}):".format(md.cluster_id, md.orig_broker_name))

    if what in ("all", "brokers"):
        print(" {} brokers:".format(len(md.brokers)))
        for b in iter(md.brokers.values()):
            if b.id == md.controller_id:
                print("  {}  (controller)".format(b))
            else:
                print("  {}".format(b))

    if what not in ("all", "topics"):
        return

    print(" {} topics:".format(len(md.topics)))
    for t in iter(md.topics.values()):
        if t.error is not None:
            errstr = ": {}".format(t.error)
        else:
            errstr = ""

        print("  \"{}\" with {} partition(s){}".format(t, len(t.partitions), errstr))

        for p in iter(t.partitions.values()):
            if p.error is not None:
                errstr = ": {}".format(p.error)
            else:
                errstr = ""

            print("    partition {} leader: {}, replicas: {}, isrs: {}".format(
                p.id, p.leader, p.replicas, p.isrs, errstr))


if __name__ == '__main__':
    if len(sys.argv) < 3:
        sys.stderr.write('Usage: %s <bootstrap-brokers> <operation> <args..>\n\n' % sys.argv[0])
        sys.stderr.write('operations:\n')
        sys.stderr.write(' create_topics <topic1> <topic2> ..\n')
        sys.stderr.write(' delete_topics <topic1> <topic2> ..\n')
        sys.stderr.write(' create_partitions <topic1> <new_total_count1> <topic2> <new_total_count2> ..\n')
        sys.stderr.write(' describe_configs <resource_type1> <resource_name1> <resource2> <resource_name2> ..\n')
        sys.stderr.write(' alter_configs <resource_type1> <resource_name1> ' +
                         '<config=val,config2=val2> <resource_type2> <resource_name2> <config..> ..\n')
        sys.stderr.write(' delta_alter_configs <resource_type1> <resource_name1> ' +
                         '<config=val,config2=val2> <resource_type2> <resource_name2> <config..> ..\n')
        sys.stderr.write(' list [<all|topics|brokers>]\n')
        sys.exit(1)

    broker = sys.argv[1]
    operation = sys.argv[2]
    args = sys.argv[3:]

    # Create Admin client
    a = AdminClient({'bootstrap.servers': broker})

    opsmap = {'create_topics': example_create_topics,
              'delete_topics': example_delete_topics,
              'create_partitions': example_create_partitions,
              'describe_configs': example_describe_configs,
              'alter_configs': example_alter_configs,
              'delta_alter_configs': example_delta_alter_configs,
              'list': example_list}

    if operation not in opsmap:
        sys.stderr.write('Unknown operation: %s\n' % operation)
        sys.exit(1)

    opsmap[operation](a, args)