XORC Notifications

A collection of services consuming PushNotification events to send push notifications to apns2/fcm/web push and Application events to receive configuration.

The systems are by default multi-tenant for sending push notifications to multiple different applications.

• apns2 for Apple notifications
• fcm for Google notificiations
• web_push for Web push notifications
• http_requester for generic HTTP requests
• common a library used by all four consumers

Installation

The consumers can be installed through Cargo:

> cargo install xorc-notifications

It installs four different binaries: apns2, fcm, web_push and http_requester, all named after the systems they present.

Environment variables

variable	description	example
CONFIG	The configuration file location	/etc/xorc-notifications/config.toml
LOG_FORMAT	Log output format	text or json, default: text
RUST_ENV	The program environment	test, development, staging or production, default: development

Required options

section	key	description	example
[kafka]	input_topic	Notification input topic	"production.notifications.apns"
[kafka]	config_topic	Application configuration topic	"production.applications"
[kafka]	output_topic	Notification response topic	"production.oam"
[kafka]	group_id	Consumer group ID	"production.consumers.apns"
[kafka]	brokers	Comma-separated list of Kafka brokers	"kafka1:9092,kafka2:9092"
[kafka]	consumer_type	Decides the input protobuf deserialization	push_notification for PushNotification, http_request for HttpRequest

Dependencies

The systems are written with Rust and it should always be possible to compile with the latest stable version. The de-facto way of getting the latest Rust is with rustup:

> curl https://sh.rustup.rs -sSf | sh
> rustup update
> rustup default stable

To check that everything works:

> rustc --version
rustc 1.30.0 (da5f414c2 2018-10-24)
> cargo --version
cargo 1.30.0 (36d96825d 2018-10-24)

Some of the crates used in the project have dependencies to certain system libraries and tools, for Ubuntu 18.04 you get them with:

> sudo apt install build-essential libssl-dev automake ca-certificates libffi-dev protobuf-compiler

Development setup

The project uses Protocol Buffers for event schemas. cargo build should generate the corresponding Rust structs to be used in the code. By default the protobuf classes are included as a submodule, which must be imported to the project tree:

> git submodule update --init

Configuration examples for all the consumers are in config. Create a copy from an example config removing the ending, and modify it to suit your test setup.

Running apns2:

> env CONFIG=./config/apns2.toml cargo run --bin apns2

Running fcm:

> env CONFIG=./config/fcm.toml cargo run --bin fcm

Running web_push:

> env CONFIG=./config/web_push.toml cargo run --bin web_push

Running http_requester:

> env CONFIG=./config/http_requester.toml cargo run --bin http_requester

Example scripts for testing purposes

The examples directory contains helper scripts for testing the consumers.

To build them:

cargo build --release --examples

The executables are in target/release directory.

Configuration

The system is configuration is handled through a toml file and a environment variable.

Code Architecture

• All four systems use an asynchronous Kafka consumer consuming the input_topic, requesting the external service with a client, parsing the response and responding back to the caller.
• System should implement the EventHandler (request_consumer.rs) and respond with ResponseProducer (response_producer.rs).
• Consumer should keep track of connections for different applications using the configuration values from the config_topic.
• In general none of the main code should never block.
• All consumers talk HTTP and when requested, return Prometheus statistics