[](https://travis-ci.org/peburrows/kane)
# Kane
Kane. Citizen Kane. Charles Foster Kane, to be exact, Publisher extraordinaire. Rosebud.
Kane is for publishing and subscribing to topics using Google Cloud Pub/Sub.
## Installation
1. Add Kane to your list of dependencies in `mix.exs`:
```elixir
def deps do
[{:kane, "~> 0.2.0"}]
end
```
2. Configure [Goth](https://github.com/peburrows/goth) (Kane's underlying token storage and retrieval library) with your Google JSON credentials:
```elixir
config :goth,
json: "path/to/google/json/creds.json" |> File.read!
```
3. Ensure Kane is started before your application:
```elixir
def application do
[applications: [:kane]]
end
```
## Usage
Pull, process and acknowledge messages via a pre-existing subscription:
```elixir
subscription = %Kane.Subscription{topic: %Kane.Topic{name: "my-topic"}}
{:ok, messages} = Kane.Subscription.pull(subscription)
Enum.each messages, fn(mess)->
process_message(mess)
end
# acknowledge message receipt in bulk
Kane.Subscription.ack(subscription, messages)
```
Send message via pre-existing subscription:
```elixir
topic = %Kane.Topic{name: "my-topic"}
message = %Kane.Message{data: %{"hello": "world"}, attributes: %{"random" => "attr"}}
result = Kane.Message.publish(message, topic)
case result do
{:ok, _return} -> IO.puts("It worked!")
{:error, _reason} -> IO.puts("Should we try again?")
end
```
Hints:
- Attributes have to be Strings (https://cloud.google.com/pubsub/docs/reference/rest/v1/PubsubMessage)
- We base64-encode the message by default (only mandatory when using json - https://cloud.google.com/pubsub/publisher)
For more details, see the [documentation](http://hexdocs.pm/kane).
