Bowie

Bowie is an Apache v2 GenServer-based module that listens to your CouchDB Changes feed, based off the amazing ibrowse and icouch libraries.

Features

• OTP friendly GenServer
• transparently handles network connectivity failures
• include fully parsed document bodies, or not
• jump-start from a given sequence token instead of the beginning of time
• provides overrideable handler
• inline code documentation

Usage

While Bowie can be used directly, in the iex console, it is designed to drop into a typical OTP Supervisor tree and receive a stream of changes from it's linked ibrowse worker.

There is one overrideable function, handle_changes/1 which receives an ICouch-parsed document as a message, upon every notified change.

When your worker is initialised, the well-known CouchDB changes feed parameters are supported:

• include_docs: true to include the entire JSON-parsed document
• since: <seq>, the sequence token of the database to start streaming from

Note that in all cases, you will need to handle attachments yourself, using ICouch's excellent functionality, it makes no sense to stream potentially MB or GB of attachment data.

Let's make an example Bowie Changes worker:

couch = "http://admin:[email protected]:5984/"
db = Bowie.db(couch, "_users")
flags = [include_docs: true]
args = [db, flags]
workers = [%{id: My.Worker, start: {Bowie, :start_link, args}}]
options = [strategy: :one_for_one, name: My.Supervisor]
Supervisor.start_link( workers, options )

Installation

If available in Hex, the package can be installed by adding bowie to your list of dependencies in mix.exs:

def deps do
  [
    {:bowie, "~> 0.9.0"}
  ]
end

Apache v2 license

Copyright 2018-2038, SkunkWerks, GmbH

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.