https://github.com/marselester/dynconf
Dynamic service configuration with etcd.
https://github.com/marselester/dynconf
dynamic-configuration etcd
Last synced: about 1 month ago
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Dynamic service configuration with etcd.
- Host: GitHub
- URL: https://github.com/marselester/dynconf
- Owner: marselester
- Created: 2021-11-26T22:47:54.000Z (over 3 years ago)
- Default Branch: master
- Last Pushed: 2021-12-06T22:06:15.000Z (over 3 years ago)
- Last Synced: 2024-06-20T06:37:08.854Z (11 months ago)
- Topics: dynamic-configuration, etcd
- Language: Python
- Homepage:
- Size: 40 KB
- Stars: 0
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Dynamic service configuration
This Go package provides a dynamic service configuration backed by etcd,
so there should be no need to redeploy a service to change its settings.
For example, project Curiosity expects settings such as `velocity = 10` and `is_camera_enabled = true`.
Let's save them in etcd with a path prefix `/configs/curiosity/`.
```sh
$ brew install etcd
$ etcd
$ etcdctl put /configs/curiosity/velocity 10
OK
$ etcdctl put /configs/curiosity/is_camera_enabled true
OK
```
On the service side the settings are fetched from the same path.
```go
const defaultVelocity = 5
c, err := dynconf.New("/configs/curiosity/")
if err != nil {
// No worries if etcd is down, the rover can still roll with the default settings.
}
defer c.Close()
rover.SetVelocity(
c.Int("velocity", defaultVelocity),
)
```
## Testing
Run etcd (`127.0.0.1:2379` by default) and then launch the tests.
```sh
$ etcd
$ go test -count=1 .
```
### Toxiproxy
With [Toxiproxy](https://github.com/Shopify/toxiproxy) you can simulate network conditions.
All communication with the Toxiproxy daemon from the client happens via HTTP on port 8474.
```sh
$ brew install toxiproxy
$ toxiproxy-server
INFO[0000] API HTTP server starting host=localhost port=8474 version=2.2.0
```
Create a proxy called `dynconf_etcd` that listens on port `22379`
and proxies traffic to etcd running on `2379` port.
```sh
$ toxiproxy-cli create --listen localhost:22379 --upstream localhost:2379 dynconf_etcd
Created new proxy dynconf_etcd
$ toxiproxy-cli list
Name Listen Upstream Enabled Toxics
======================================================================================
dynconf_etcd 127.0.0.1:22379 localhost:2379 enabled None
```
Check that etcd is reachable via Toxiproxy.
```sh
$ etcdctl --endpoints=127.0.0.1:22379 get /configs/curiosity/velocity
OK
```
Add 1500ms downstream latency.
```sh
$ toxiproxy-cli toxic add --type latency --attribute latency=1500 dynconf_etcd
$ toxiproxy-cli inspect dynconf_etcd
Name: dynconf_etcd Listen: 127.0.0.1:22379 Upstream: localhost:2379
======================================================================
Upstream toxics:
Proxy has no Upstream toxics enabled.
Downstream toxics:
latency_downstream: type=latency stream=downstream toxicity=1.00 attributes=[ jitter=0 latency=5000 ]
```
There should be 1.5s latency introduced.
You can remove `latency_downstream` afterwards.
```sh
$ etcdctl --endpoints=127.0.0.1:22379 get /configs/curiosity/velocity
OK
$ toxiproxy-cli toxic remove -n latency_downstream dynconf_etcd
Removed toxic 'latency_downstream' on proxy 'dynconf_etcd'
```
There are more [toxics](https://github.com/Shopify/toxiproxy#toxics) available.
For example, stop all data from getting through, and close the connection after 10s.
```sh
$ toxiproxy-cli toxic add --type timeout --attribute timeout=10000 dynconf_etcd
Added downstream timeout toxic 'timeout_downstream' on proxy 'dynconf_etcd'
$ toxiproxy-cli toxic remove -n timeout_downstream dynconf_etcd
```
Simulate TCP RESET (Connection reset by peer) by closing connections after 10s.
```sh
$ toxiproxy-cli toxic add --type reset_peer --attribute timeout=10000 dynconf_etcd
Added downstream reset_peer toxic 'reset_peer_downstream' on proxy 'dynconf_etcd'
$ toxiproxy-cli toxic remove -n reset_peer_downstream dynconf_etcd
```