Mikkoo is a PgQ to RabbitMQ Relay

amqp, rabbitmq, postgresql
pip install mikkoo==1.1.2



A PgQ to RabbitMQ relay. Mikkoo is a PgQ consumer that that publishes to RabbitMQ. In addition, it includes a built in auditing system that can be used to confirm that all PgQ events are received by RabbitMQ.

Mikkoo is named for the rabbit in the "Clever Rabbit and the Elephant" fable.

Version Downloads Status


Mikkoo is available on the Python Package Index and can be installed via pip:

pip install mikkoo

Once you've setup Skytools you may want to install the optional included utility functions in mikkoo.sql to make usage easier.

You can do this with a combination of curl and psql:

curl -L https://github.com/gmr/mikkoo/blob/master/mikkoo.sql | psql

This will install multiple stored procedures and an audit table in a mikkoo schema. Take a look at the DDL to get a good idea of what each funciton is and how it can be used.

PgQ Setup

  1. Install pgq into your database and create the queue:

    # SELECT pgq.create_queue('test');
    (1 row)
  2. Ensure that pgqd is running.

PgQ Event to AMQP Mapping

When inserting events into a PgQ queue, the pgq.insert_event/7 function should be used with the following field mappings:

PgQ Event AMQP
ev_type Routing Key
ev_data Message body
ev_extra1 Exchange
ev_extra2 Content-Type Property
ev_extra3 AMQP Properties [1]
ev_extra4 Headers [2]
ev_time Headers.timetamp
ev_txid Headers.txid
[1] AMQP properties should be set as a JSON blob. Values set in the ev_extra3 field will overwrite the automatically created properties app_id, content_type, correlation_id, headers, and timestamp.
[2] If ev_extra4 is specified and is a JSON key/value dictionary, it will be assigned to the headers AMQP property.

There is a convenience schema in the mikkoo.sql file that adds stored procedures for creating properly formatted mikkoo events in PgQ. In addition, there is are auditing functions that allow for the creation of an audit-log of events that were sent to PgQ.

AMQP Message Properties

The following table defines the available fields that can be set in a JSON blob in the ev_extra3 field when inserting an event.

Property PgSQL Type
app_id text
content_encoding text
content_type text
correlation_id text
delivery_mode int2
expiration text
message_id text
headers text/json [3]
timestamp int4
type text
priority int4
user_id text
[3] headers should be sent to a key/value JSON blob if specified

Values assigned in the JSON blob provided to ev_extra3 take precedence over the automatically assigned app_id, content_type, correlation_id, headers, and timestamp values created by Mikkoo at processing time.

As of 1.0, Mikkoo will automatically add four AMQP headers property values. These values will not overwrite any values with the same name specified in ev_extra4. overwriting values with the same name, even if they are specified in the The sequence value is a dynamically generated ID that attempts to provide fuzzy distributed ordering information. The timestamp value is the ISO-8601 representation of the ev_time field, which is created when an event is added to PgQ. The txid value is the ev_txid value, the PgQ transaction ID for the event. These values are added to help provide some level of deterministic ordering. The origin value is the hostname of the server that Mikkoo is running on.

Event Insertion Example

The following example inserts a JSON blob message body of {"foo": "bar"} that will be published to the postgres exchange in RabbitMQ using the test.routing-key routing key. The content type is specified in ev_extra2 and the AMQP type message property is specified in ev_extra3.

# SELECT pgq.insert_event('test', 'test.routing-key', '{"foo": "bar"}', 'postgres', 'application/json', '{"type": "example"}', '');
(1 row)

When this message is received by RabbitMQ it will have a message body of:

{"foo": "bar"}

And it will have message properties similar to the following:

Property Example Value
app_id mikkoo
content_type application/json
correlation_id 0ad6b212-4c84-4eb0-8782-9a44bdfe949f
Key Example Value
origin mikkoo.domain.com
sequence 4539586784185129828
timestamp 2017-02-23 06:17:14.471682-00
txid 41356335556
timestamp 1449600290
type example


The Mikkoo configuration file uses YAML for markup and allows for one or more PgQ queue to be processed.

If you have a Sentry or a Sentry account, the Application/sentry_dsn setting will turn on sentry exception logging, if the raven client library is installed.

Queues are configured by name under the Application/workers stanza. The following example configures two workers for the processing of a queue named invoices. Each worker process connects to a local PostgreSQL and RabbitMQ instance using default credentials.

       postgres_url: postgresql://localhost:5432/postgres
       rabbitmq_url: amqp://localhost:5672/%2f
       confirm: False

Queue Configuration Options

The following table details the configuration options available per queue:

Key Description
confirm Enable/Disable RabbitMQ Publisher Confirmations. Default: True
consumer_name Overwrite the default PgQ consumer name. Default: mikkoo
max_failures Maximum failures before discarding an event. Default: 10
postgresql_url The url for connecting to PostgreSQL
rabbitmq_url The AMQP url for connecting to RabbitMQ
retry_delay How long in seconds until PgQ emits failed events. Default: 10
unregister Unregister a consumer with PgQ on shutdown. Default: True
wait_duration How long to wait before checking the queue after the last empty result. Default: 1

Example Configuration

The following is an example of a full configuration file:


  poll_interval: 10
  sentry_dsn: [YOUR SENTRY DSN]

    enabled: true
    host: localhost
    port: 8125

      confirm: False
      consumer_name: my_consumer
      max_failures: 5
      postgres_url: postgresql://localhost:5432/postgres
      rabbitmq_url: amqp://localhost:5672/%2f
      retry_delay: 5
      unregister: False
      wait_duration: 5

  user: mikkoo
  pidfile: /var/run/mikkoo

  version: 1
      format: '%(levelname) -10s %(asctime)s  %(process)-6d %(processName) -20s %(name) -18s: %(message)s'
      datefmt: '%Y-%m-%d %H:%M:%S'
      class: logging.StreamHandler
      formatter: verbose
      debug_only: True
      handlers: [console]
      level: INFO
      propagate: true
      handlers: [console]
      level: INFO
      propagate: true
      handlers: [console]
      level: ERROR
      propagate: true
      handlers: [console]
      level: ERROR
      propagate: true
      handlers: [console]
      level: ERROR
      propagate: true
    handlers: [console]
    level: CRITICAL
    propagate: true
  disable_existing_loggers: true
  incremental: false

Running Mikkoo

After creating a configuration file for Mikkoo like the one above, simply run the mikkoo application providing the path to the configuration file:

mikkoo -c mikkoo.yml

The application will attempt to daemonize unless you use the -f foreground CLI switch.

Mikkoo's CLI help can be invoked with --help and yields the following output:

$ mikkoo -h
usage: mikkoo [-h] [-c CONFIG] [-f]

Mikkoo is a PgQ to RabbitMQ Relay

optional arguments:
  -h, --help            show this help message and exit
  -c CONFIG, --config CONFIG
                        Path to the configuration file
  -f, --foreground      Run the application interactively