notifications-push

README

notifications-push

Notifications-push is a microservice that provides push notifications of publications or changes of articles and lists of content. The microservice consumes a specific Apache Kafka topic group, then it pushes a notification for each article or list available in the consumed Kafka messages.

How to Build & Run the binary

1. Install, build and test:

go get github.com/Financial-Times/notifications-push
cd $GOPATH/src/github.com/Financial-Times/notifications-push

go test ./... -race
go install

1. Run locally:

• Create tunnel to the Kafka service inside the cluster for ports 2181 and 9092 (use the public IP):

kubectl port-forward service/kafka-zookeeper 2181
kubectl port-forward kafka-0 9092

• Add the private DNS of the Kafka machine to the hosts file:

127.0.0.1       <private_dns> 

• Start the service using environment variables:

export NOTIFICATIONS_RESOURCE=content \
    && export KAFKA_ADDRS=localhost:2181 \
    && export GROUP_ID=notifications-push-yourtest \
    && export TOPIC=PostPublicationEvents \
    && export NOTIFICATIONS_DELAY=10 \
    && export API_BASE_URL="http://api.ft.com" \
    && export CONTENT_TYPE_WHITELIST="application/vnd.ft-upp-article+json,application/vnd.ft-upp-content-package+json" \
    && export CONTENT_URI_WHITELIST="^http://(methode|wordpress|content)-(article|collection|content-placeholder)-(transformer|mapper|unfolder)(-pr|-iw)?(-uk-.*)?\\.svc\\.ft\\.com(:\\d{2,5})?/(content)/[\\w-]+.*$" \
    && ./notifications-push

• or via command-line parameters:

./notifications-push \
    --notifications_resource="content" \
    --consumer_addr="localhost:2181" \
    --consumer_group_id="notifications-push" \
    --topic="PostPublicationEvents" \
    --notifications_delay=10 \
    --api_base_url="http://api.ft.com" \
    --api_key_validation_endpoint="t800/a" \
    --content_type_whitelist="application/vnd.ft-upp-article+json" --content_type_whitelist="application/vnd.ft-upp-content-package+json" \
    --content_uri_whitelist="^http://(methode|wordpress|content)-(article|collection|content-placeholder)-(transformer|mapper|unfolder)(-pr|-iw)?(-uk-.*)?\\.svc\\.ft\\.com(:\\d{2,5})?/(content)/[\\w-]+.*$"

NB: for the complete list of options run ./notifications-push -h

HTTP endpoints

curl -i --header "x-api-key: «api_key»" https://api.ft.com/content/notifications-push

The following subscription types could be also specified for which the client would like to receive notifications by setting a "type" parameter on the request:

• Article
• ContentPackage
• Audio
• All- all content changes including CPH, but not annotation changes.
• Annotations - notifications for manual annotation changes

If not specified, by default Article is used. If an invalid type is requested an HTTP 400 Bad Request is returned.

E.g. curl -i --header "x-api-key: «api_key»" https://api.ft.com/content/notifications-push?type=Article

Filter DELETE messages by type

When a content has been deleted (http://www.ft.com/thing/ThingChangeType/DELETE), the kafka payload is empty and we cannot extract the content type from the message. In this case, there are 2 possible behaviours:

• if the Content-Type header is empty or equal to application-json, then we cannot resolve the content type of the message. Therefore, the notification will be sent to all the subscribers despite their accepted content type.
• if the Content-Type header has been specified and it is not equal to application-json, then we can resolve the content type based on this header.

e.g. a DELETE message with header Content-Type: application/vnd.ft-upp-audio+json will be considered an Audio content. Therefore, the notification will be sent to those subscribers who accept type=Audio or type=All, but not type=Annotations.

Content Push stream

By opening a HTTP connection with a GET method to the /{resource}/notifications-push endpoint, subscribers can consume the notifications push stream for the resource specified in the configuration (content or lists). The stream will look like the following one.

data: []

data: []

data: [{"apiUrl":"http://api.ft.com/content/648bda7b-1187-3496-b48e-57ecb14d5b0a","id":"http://www.ft.com/thing/648bda7b-1187-3496-b48e-57ecb14d5b0a","type":"http://www.ft.com/thing/ThingChangeType/UPDATE","title":"For Ioana & Ioana only;","standout":{"scoop":true}}]

data: []

data: []

data: []

data: [{"apiUrl":"http://api.ft.com/content/e2e49a44-ef3c-11e5-aff5-19b4e253664a","id":"http://www.ft.com/thing/e2e49a44-ef3c-11e5-aff5-19b4e253664a","type":"http://www.ft.com/thing/ThingChangeType/UPDATE","title":"For Ioana 2","standout":{"scoop":false}}]

data: []

data: [{"apiUrl":"http://api.ft.com/content/d38489fa-ecf4-11e5-888e-2eadd5fbc4a4","id":"http://www.ft.com/thing/d38489fa-ecf4-11e5-888e-2eadd5fbc4a4","type":"http://www.ft.com/thing/ThingChangeType/UPDATE","title":"For Ioana 3","standout":{"scoop":false}}]

data: [{"apiUrl":"http://api.ft.com/content/648bda7b-1187-3496-b48e-57ecb14d5b0a","id":"http://www.ft.com/thing/648bda7b-1187-3496-b48e-57ecb14d5b0a","type":"http://www.ft.com/thing/ThingChangeType/UPDATE","title":"For Ioana 4","standout":{"scoop":false}}]

data: [{"apiUrl":"http://api.ft.com/content/648bda7b-1187-3496-b48e-57ecb14d5b0a","id":"http://www.ft.com/thing/648bda7b-1187-3496-b48e-57ecb14d5b0a","type":"http://www.ft.com/thing/ThingChangeType/UPDATE","title":"For Ioana 4","standout":{"scoop":false}}]

The empty [] lines are heartbeats. Notifications-push will send a heartbeat every 30 seconds to keep the connection active.

Annotations Push Stream

curl -i --header "x-api-key: «api_key»" https://api.ft.com/content/notifications-push?type=Annotations

By opening a HTTP connection with a GET method to the /content/notifications-push?type=Annotations endpoint, subscribers can consume the notifications push stream for annotation changes. The stream will look similar to the content one.

Message format

{
  "apiUrl":"http://api.ft.com/content/4de8b414-c5aa-11e9-a8e9-296ca66511c9",
  "id":"http://www.ft.com/thing/4de8b414-c5aa-11e9-a8e9-296ca66511c9",
  "type":"http://www.ft.com/thing/ThingChangeType/ANNOTATIONS_UPDATE"
}

Monitoring

The notifications-push stream endpoint allows a monitor query parameter. By setting the monitor flag as true, the push stream returns publishReference and lastModified attributes in the notification message, which is necessary information for UPP internal monitors such as PAM.

To test the stream endpoint you can run the following CURL commands :

curl -X GET "http://localhost:8080/content/notifications-push"
curl -X GET "http://localhost:8080/content/notifications-push?monitor=true"
curl -X GET "https://<user>@<password>:pre-prod-up.ft.com/content/notifications-push"

WARNING: In CoCo, this endpoint does not work under /__notifications-push/. The reason for this is because Vulcan does not support long polling of HTTP requests. We worked around this issue by forwarding messages through Varnish to a fixed port for both services.

Productionizing Push API: The API Gateway does not support long polling of HTTP requests, so the requests come through Fastly. Everytime a client tries to connect to Notifications Push, the service performs a call to the API Gateway in order to validate the API key from the client.

Notification history

A HTTP GET to the /__history endpoint will return the history of the last notifications consumed from the Kakfa queue. The expected payload should look like the following one:

[
	{
		"apiUrl": "http://api.ft.com/content/eabefe3e-a4b9-11e6-8b69-02899e8bd9d1",
		"id": "http://www.ft.com/thing/eabefe3e-a4b9-11e6-8b69-02899e8bd9d1",
		"type": "http://www.ft.com/thing/ThingChangeType/UPDATE",
		"publishReference": "tid_jwhfe7n6dj",
		"lastModified": "2016-11-07T13:59:44.950Z"
	},
	{
		"apiUrl": "http://api.ft.com/content/c92d7b0c-a4c7-11e6-8b69-02899e8bd9d1",
		"id": "http://www.ft.com/thing/c92d7b0c-a4c7-11e6-8b69-02899e8bd9d1",
		"type": "http://www.ft.com/thing/ThingChangeType/UPDATE",
		"publishReference": "tid_owd5zqw11m",
		"lastModified": "2016-11-07T13:59:04.546Z"
	},
	{
		"apiUrl": "http://api.ft.com/content/58437fc0-a4f1-11e6-8898-79a99e2a4de6",
		"id": "http://www.ft.com/thing/58437fc0-a4f1-11e6-8898-79a99e2a4de6",
		"type": "http://www.ft.com/thing/ThingChangeType/DELETE",
		"publishReference": "tid_5z8dxzsesj",
		"lastModified": "2016-11-07T13:58:36.285Z"
	}
]

Stats

A HTTP GET to the /__stats endpoint will return the stats about the current subscribers that are consuming the notifications push stream The expected payload should look like the following one:

{
	"nrOfSubscribers": 2,
	"subscribers": [
		{
			"addr": "127.0.0.1:61047",
			"since": "Nov  7 14:26:04.018",
			"connectionDuration": "2m41.693365011s",
			"type": "dispatcher.standardSubscriber"
		},
		{
			"addr": "192.168.1.3:65345",
			"since": "Nov  7 14:26:06.259",
			"connectionDuration": "2m39.453175004",
			"type": "dispatcher.monitorSubscriber"
		}
	]
}

How to Build & Run with Docker

    docker build -t coco/notifications-push .

    docker run --env NOTIFICATIONS_RESOURCE=content \
        --env KAFKA_ADDRS=localhost:2181 \
        --env GROUP_ID="notifications-push-yourtest" \
        --env TOPIC="PostPublicationEvents" \
        --env NOTIFICATIONS_DELAY=10 \
        --env API_BASE_URL="http://api.ft.com" \
        --env CONTENT_TYPE_WHITELIST="application/vnd.ft-upp-article+json,application/vnd.ft-upp-content-package+json" \
        --env CONTENT_URI_WHITELIST="^http://(methode|wordpress|content)-(article|collection)-(transformer|mapper|unfolder)(-pr|-iw)?(-uk-.*)?\\.svc\\.ft\\.com(:\\d{2,5})?/(content)/[\\w-]+.*$" \
        coco/notifications-push

Clients

Example client code is provided in bin/client directory

Logging

• The application uses go-logger; the log file is initialised in app.go.

Useful Links

• Production:

https://api.ft.com/content/notifications-push (needs API key)

• For internal use:

https://prod-coco-up-read.ft.com/content/notifications-push (needs credentials)

https://prod-coco-up-read.ft.com/lists/notifications-push (needs credentials)