monkut

# referecing: # https://www.digitalocean.com/community/tutorials/how-to-install-apache-kafka-on-ubuntu-14-04 # https://chongyaorobin.wordpress.com/2015/07/08/step-by-step-of-install-apache-kafka-on-ubuntu-standalone-mode/

1. Add 'kafka' user:

$ sudo useradd kafka -m

2. Install Java:

ursuad

Kafka Topics

List existing topics

bin/kafka-topics.sh --zookeeper localhost:2181 --list

Describe a topic

bin/kafka-topics.sh --zookeeper localhost:2181 --describe --topic mytopic

Purge a topic

bin/kafka-topics.sh --zookeeper localhost:2181 --alter --topic mytopic --config retention.ms=1000

... wait a minute ...

douglasmiranda

# This is a really old post, in the comments (and stackoverflow too) you'll find better solutions.

def find(key, dictionary):
    for k, v in dictionary.iteritems():
        if k == key:
            yield v
        elif isinstance(v, dict):
            for result in find(key, v):
                yield result
        elif isinstance(v, list):

rantav

In mongodb it's easy to make at upsert, meaning update-or-insert by calling

db.collection.update({criteria}, {updated fields}, true)

The third parameter means - insert a new document if the document doesn't exist yet. So, for example, the following will insert a new document for the user if there's no document for that user yet, and will update it if it already exists:

 db.users.update({user_id: '1234'}, {user_id: '1234', name: 'Ran'}, true)