mirror of
https://github.com/openfaas/faas.git
synced 2025-06-16 12:16:47 +00:00
a1c2c553a5
Added scale_from_zero to config, docs and wrote unit test for the value. Signed-off-by: Alex Ellis (VMware) <alexellis2@gmail.com>
60 lines
3.5 KiB
Markdown
60 lines
3.5 KiB
Markdown
# 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:
|
|
|
|
* UI built-in
|
|
* Deploy your own functions or from the Function Store
|
|
* Instrumentation via Prometheus
|
|
* Auto-scaling via AlertManager
|
|
* REST API available
|
|
|
|
|
|
|
|
*Pictured: conceptual architecture when Kubernetes is used as the orchestration provider*
|
|
|
|
## Function Providers
|
|
|
|
Providers for functions can be written using the [faas-provider](https://github.com/openfaas/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](https://github.com/openfaas/faas-swarm/).
|
|
|
|
## REST API
|
|
|
|
Swagger docs: https://github.com/openfaas/faas/tree/master/api-docs
|
|
|
|
## 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](https://github.com/openfaas/faas-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 without passing through 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 |
|