Neurow

Push from backends to frontend at scale

Repository content

This git repository contains:

• The Neurow server in the /neurow directory.
• Load tests in the /load_test directory.

Both are independent Elixir mix applications.

Neurow

All commands provided here must be run in the /neurow directory

Setup and start Neurow locally

• Install the latest version of Elixir by following instructions provided here,
• Run mix deps.get to download the dependencies required by Neurow,
• Run mix run --no-halt to start Neurow locally with the default development configuration. The public API is then available on http://localhost:4000 and the internal API on http://localhost:3000.

It is possible to override the default local configuration with environment variables. For example to run Neurow on custom ports: PUBLIC_API_PORT=5000 INTERNAL_API_PORT=5000 mix run --no-halt

Available environment variables are:

Name	Default value	Role
LOG_LEVEL	info	Log level
LOG_FORMAT	TEXT	Log format, possible values: TEXT - space separated attributes, ECS - JSON format compatible with the Elastic Common Schema
PUBLIC_API_PORT	4000	TCP port of the public API
PUBLIC_API_JWT_MAX_LIFETIME	120	Max lifetime in seconds allowed for JWT tokens issued on the public API
PUBLIC_API_CONTEXT_PATH	""	URL prefix for resources of the public API - Useful to mount Neurow on a existing website
PREFLIGHT_MAX_AGE	86400	Value of the access-control-max-age headers on CROS preflight responses on the public API
SSE_TIMEOUT	900000	SSE deconnection delay in ms, after the last received message
SSE_KEEPALIVE	600000	Neurow periodically send ping events on SSE connections to prevent connections from being closed by network devices. This variable defines the delay between two ping events in milliseconds.
MAX_HEADER_VALUE_LENGTH	8192	Max http request headers size, as expected by the cowboy HTTP server here
INTERNAL_API_PORT	3000	TCP port fo the internal API
INTERNAL_API_JWT_MAX_LIFETIME	1500	Max lifetime in seconds allowed for JWT tokens issued on the internal API
HISTORY_MIN_DURATION	30	Messages are persisted in the Neurow cluster, so clients can re-fetch recent messages after a short term disconnection by using the Last-Event-Id on SSE connections. Messages are only persisted for a limited time. HISTORY_MIN_DURATION defines the minimum retention guaranteed by the Neurow server.

Generate JWT tokens for the local environment

Both the public and internal APIs rely on JWT tokens for authentication. For now JWT tokens are signed tokens with shared secret keys. Assymetric signatures will be supported later.

Developement issuers and their signature keys are hard coded in config/runtimes.exs:51. The available issuers are test_issuer1 and test_issuer2.

To generate a JWT token for the public API, run: mix generate_jwt_token --api=public --issuer=<issuer name> --topic=<topic name>

To generate a JWT token for the internal API, run: mix generate_jwt_token --api=internal --issuer=<issuer name>

Run tests

• mix test runs all tests (both unit and integration tests)
• mix test.unit runs unit tests
• mix test.integration run integration tests

Load tests

WIP