0f5ca96bbe
When the /system/info endpoint was expanded to include information about the gateway a number of build-args were added to the main Dockerfile. These changes were not mirrored in Dockerfile.armhf, which resulted in nil attributes and an ugly error when running `faas version` against an armhf gateway. This change carries the changes made to Dockerfile through to Dockerfile.armhf. As well as the build-args which fix the identified issue the license check has also been added at the latest release 0.2.3, as a armhf build has been made available. Further changes are to introduce the app user and moving the binary location from /root/ to /home/app/ Signed-off-by: Richard Gee <richard@technologee.co.uk>
Gateway
The API Gateway provides an external route into your functions and collects Cloud Native metrics through Prometheus. The gateway also has a UI built-in which can be used to deploy your own functions or functions from the OpenFaaS Function Store then invoke them.
The gateway will scale functions according to demand by altering the service replica count in the Docker Swarm or Kubernetes API. Custom alerts generated by AlertManager are received on the /system/alert endpoint.
In summary:
- Built-in UI Portal
- Deploy functions from the Function Store or deploy your own
- Instrumentation via Prometheus
- Auto-scaling via AlertManager and Prometheus
- Scaling up from zero
- REST API available documented with Swagger
Pictured: conceptual architecture when Kubernetes is used as the orchestration provider
Function Providers
Providers for functions can be written using the faas-provider interface in Golang which provides the REST API for interacting with the gateway. The gateway originally interacted with Docker Swarm directly and anything else via a Function Provider - this support was moved into a separate project faas-swarm.
REST API
Swagger docs: https://github.com/openfaas/faas/tree/master/api-docs
CORS
By default the only CORS path allowed is for the Function Store which is served from the GitHub RAW CDN.
UI Portal
The built-in UI Portal is served through static files bound at the /ui/ path.
The UI was written in Angular 1.x and makes uses of jQuery for interactions and the Angular Material theme for visual effects and components.
View the source in the assets folder.
Function Store
The Function Store is rendered through a static JSON file served by the GitHub RAW CDN. The Function Store can also be used via the OpenFaaS CLI.
See the openfaas/store repo for more.
Logs
Logs are available at the function level and can be accessed through Swarm or Kubernetes using native tooling. You can also install a Docker logging driver to aggregate your logs. By default functions will not write the request and response bodies to stdout. You can toggle this behaviour by setting read_debug for the request and write_debug for the response.
Tracing
An "X-Call-Id" header is applied to every incoming call through the gateway and is usable for tracing and monitoring calls. We use a UUID for this string.
Header:
X-Call-Id
Within a function this is available as Http_X_Call_Id.
Environmental overrides
The gateway can be configured through the following environment variables:
| Option | Usage |
|---|---|
write_timeout |
HTTP timeout for writing a response body from your function (in seconds). Default: 8 |
read_timeout |
HTTP timeout for reading the payload from the client caller (in seconds). Default: 8 |
functions_provider_url |
URL of upstream functions provider - i.e. Swarm, Kubernetes, Nomad etc |
faas_nats_address |
Address of NATS service. Required for asynchronous mode |
faas_nats_port |
Port for NATS service. Requrired for asynchronous mode |
faas_prometheus_host |
Host to connect to Prometheus. Default: "prometheus" |
faas_promethus_port |
Port to connect to Prometheus. Default: 9090 |
direct_functions |
true or false - functions are invoked directly over overlay network by DNS name without passing through the provider |
direct_functions_suffix |
Provide a DNS suffix for invoking functions directly over overlay network |
basic_auth |
Set to true or false to enable embedded basic auth on the /system and /ui endpoints (recommended) |
secret_mount_path |
Set a location where you have mounted basic-auth-user and basic-auth-password, default: /run/secrets/. |
scale_from_zero |
Enables an intercepting proxy which will scale any function from 0 replicas to the desired amount |