https://github.com/jcmoraisjr/dory
Ask me my hostname. I'll remember you asked. :fish:
https://github.com/jcmoraisjr/dory
Last synced: 3 months ago
JSON representation
Ask me my hostname. I'll remember you asked. :fish:
- Host: GitHub
- URL: https://github.com/jcmoraisjr/dory
- Owner: jcmoraisjr
- License: apache-2.0
- Created: 2021-07-13T12:07:27.000Z (almost 4 years ago)
- Default Branch: main
- Last Pushed: 2021-07-14T00:29:53.000Z (almost 4 years ago)
- Last Synced: 2025-01-20T14:50:10.846Z (5 months ago)
- Language: Go
- Size: 14.6 KB
- Stars: 2
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# dory
[](https://github.com/jcmoraisjr/dory/actions/workflows/image.yaml) [](https://quay.io/repository/jcmoraisjr/dory)
A HTTP server that responds with the hostname where it is running on. It's usually the pod name if deployed on Kubernetes and using the pod network. `dory` also accepts the time that should be wait to respond, and how much that time should be randomly changed. `dory` has metrics, so she will remember how frequently you asked.
## use cases
`dory` can be used to:
* Test blue/green load balance, comparing how many times each host appeared in the response
* Test concurrent sessions and ephemeral port exhaustion, asking `dory` to wait a few (or lots of) seconds before send the response and finish the session
* Play with Prometheus metrics
## how to use
`dory` accepts the following command-line options:
* `-listen`: changes the listening IP and port, defaults to `:8000` (port 8000 on all IP addresses) if not declared
* `-buckets`: changes the list of the response time counter buckets, default value is `0.8,1,1.2`
The following HTTP headers are accepted:
* `x-wait`: number of milliseconds to wait before send the response, defaults to respond imediately
* `x-pct`: maximum percentage to randomly increase or decrease the configured wait time, e.g. `20` means that a wait time of `1000` will in fact wait between `800ms` and `1.2s`, dafaults to zero which means to wait exactly the configured amount of time
## example
The following steps configure an environment to test the distribution of response times and concurrent sessions during a load test. The only required dependencies are `docker` and `vegeta` [(download)](https://github.com/tsenart/vegeta/releases).
Run two `dory` instances with default parameters:
```
docker run -d --name=dory1 -p 8001:8000 jcmoraisjr/dory
docker run -d --name=dory2 -p 8002:8000 jcmoraisjr/dory
```
Problem with Docker Hub?
```
docker run -d --name=dory1 -p 8001:8000 quay.io/jcmoraisjr/dory
docker run -d --name=dory2 -p 8002:8000 quay.io/jcmoraisjr/dory
```
Configure a HAProxy to load balance between these two instances:
`h.cfg`:
```
defaults
timeout client 1m
timeout server 1m
timeout connect 5s
listen l
bind :8000
server dory1 127.0.0.1:8001
server dory2 127.0.0.1:8002
```
```
docker run -d --name=haproxy --net=host -v $PWD:/tmp:ro haproxy:alpine -f /tmp/h.cfg
```
Configure a Prometheus server to scrape metrics from these two instances:
`prometheus.yml`:
```
global:
scrape_interval: 10s
scrape_timeout: 5s
scrape_configs:
- job_name: prometheus
static_configs:
- targets:
- 127.0.0.1:9090
- job_name: dory
static_configs:
- targets:
- 127.0.0.1:8001
- 127.0.0.1:8002
```
```
docker run -d --name=prom --net=host -v $PWD:/etc/prometheus:ro prom/prometheus
```
Run the load test, the command below will run 100 requests per second during 5 minutes:
```
echo "GET http://127.0.0.1:8000" |\
vegeta attack -duration=5m -rate=100 -header "x-wait: 1000" -header "x-pct: 25" |\
vegeta report
```
The headers ask `dory` to wait between `750ms` and `1.25s` to send the response, this should fill all the buckets of our histogram, which defaults to `0.8s`, `1s` and `1.2s`.
After the load test, of even while it's still running, send the following queries to Prometheus - it should be running on `http://127.0.0.1:9090`, or maybe you need to change to the public IP of your VM.
Query the concurrent sessions - per instance:
```
dory_sessions
```
Query the percentage of response times below `0.8s` - per instance:
```
100 * sum(rate(dory_response_time_seconds_bucket{le="0.8"}[1m])) by (instance) / sum(rate(dory_response_time_seconds_count[1m])) by (instance)
```
Note that the graph won't be drawn in the example above during request rate equals to zero, this happens due to a division by zero error.
## cleanup
Need to remove all the containers and start again?
```
docker stop dory1 dory2 haproxy prom
docker rm dory1 dory2 haproxy prom
```