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minor changes in code, added better description and Kubernetes example

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This commit is contained in:
Łukasz Budnik
2020-11-14 09:01:40 +01:00
parent 4ada9bfd9c
commit ac4f9b9a94
2 changed files with 125 additions and 5 deletions
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117
README.md
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@@ -1,2 +1,117 @@
# yosoy
Yo soy is a tool for stubbing distributed applications.
yosoy is a HTTP service for stubbing distributed applications. It is a service which will introduce itself to the caller and print some useful information about its environment. "Yo soy" in español means "I am".
yosoy is extremely useful when creating a distributed application stub and you need to see a more meaningful responses than a default nginx welcome page.
yosoy will provide information like (see example below):
* Request URI
* Hostname
* Remote IP
* How many times it was called
* HTTP headers
* Env variables if `YOSOY_SHOW_ENVS` is set to `true`, `yes`, `on`, or `1`
* Files contents if `YOSOY_SHOW_FILES` is set to a comma-separated list of (valid) files
## Docker image
The docker image is available on docker hub:
```
lukasz/yosoy
```
It exposes HTTP service on port 80.
## Kubernetes example
Let's take a look at a sample Kubernetes deployment file. It uses both `YOSOY_SHOW_ENVS` and `YOSOY_SHOW_FILES`. To illustrate `YOSOY_SHOW_FILES` functionality it uses Kubernetes Downward API to expose labels and annotations as volume files which are then read by yosoy.
```
apiVersion: apps/v1
kind: Deployment
metadata:
name: camarero
labels:
app.kubernetes.io/name: camarero
spec:
replicas: 2
selector:
matchLabels:
app.kubernetes.io/name: camarero
template:
metadata:
labels:
app.kubernetes.io/name: camarero
spec:
containers:
- name: yosoy
image: lukasz/yosoy
env:
- name: YOSOY_SHOW_ENVS
value: "true"
- name: YOSOY_SHOW_FILES
value: "/etc/podinfo/labels,/etc/podinfo/annotations"
ports:
- containerPort: 80
volumeMounts:
- name: podinfo
mountPath: /etc/podinfo
volumes:
- name: podinfo
downwardAPI:
items:
- path: "labels"
fieldRef:
fieldPath: metadata.labels
- path: "annotations"
fieldRef:
fieldPath: metadata.annotations
```
Execute curl a couple of times and you should see:
```
Request URI: /
Hostname: camarero-7fd97dc5f5-545mt
Remote IP: 172.18.0.1
Called: 4
HTTP headers:
User-Agent: curl/7.58.0
Accept: */*
Env variables:
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=camarero-7fd97dc5f5-545mt
YOSOY_SHOW_ENVS=true
YOSOY_SHOW_FILES=/etc/podinfo/labels,/etc/podinfo/annotations
KUBERNETES_PORT=tcp://10.96.0.1:443
KUBERNETES_PORT_443_TCP_PROTO=tcp
CAMARERO_SERVICE_HOST=10.96.183.207
KUBERNETES_SERVICE_HOST=10.96.0.1
KUBERNETES_SERVICE_PORT=443
KUBERNETES_SERVICE_PORT_HTTPS=443
CAMARERO_SERVICE_PORT=80
CAMARERO_PORT_80_TCP_PROTO=tcp
KUBERNETES_PORT_443_TCP=tcp://10.96.0.1:443
CAMARERO_PORT_80_TCP=tcp://10.96.183.207:80
CAMARERO_PORT_80_TCP_PORT=80
KUBERNETES_PORT_443_TCP_PORT=443
KUBERNETES_PORT_443_TCP_ADDR=10.96.0.1
CAMARERO_PORT=tcp://10.96.183.207:80
CAMARERO_PORT_80_TCP_ADDR=10.96.183.207
HOME=/root
File /etc/podinfo/labels:
app.kubernetes.io/component="api"
app.kubernetes.io/name="camarero"
app.kubernetes.io/part-of="camarero"
app.kubernetes.io/version="0.0.1"
pod-template-hash="7fd97dc5f5"
File /etc/podinfo/annotations:
kubernetes.io/config.seen="2020-11-13T14:36:17.234235115Z"
kubernetes.io/config.source="api"
```

13
server.go
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@@ -15,12 +15,17 @@ var showEnvs = os.Getenv("YOSOY_SHOW_ENVS")
var showFiles = os.Getenv("YOSOY_SHOW_FILES")
func handler(w http.ResponseWriter, req *http.Request) {
fmt.Printf("[%v] - %v - %v - \"%v %v\"\n", hostname, time.Now().Format(time.RFC3339), req.RemoteAddr, req.Method, req.RequestURI)
remoteAddr := req.RemoteAddr
// LastIndex works better with IPv6
if index := strings.LastIndex(remoteAddr, ":"); index > 0 {
remoteAddr = remoteAddr[0:index]
}
fmt.Printf("[%v] - %v - %v - \"%v %v\"\n", hostname, time.Now().Format(time.RFC3339), remoteAddr, req.Method, req.RequestURI)
w.WriteHeader(200)
w.Header().Add("Content-Type", "text/plain")
fmt.Fprintf(w, "Request URI: %v\n", req.RequestURI)
fmt.Fprintf(w, "Hostname: %v\n", hostname)
fmt.Fprintf(w, "Remote IP: %v\n", req.RemoteAddr)
fmt.Fprintf(w, "Remote IP: %v\n", remoteAddr)
counter++
fmt.Fprintf(w, "Called: %v\n", counter)
fmt.Fprintln(w)
@@ -30,7 +35,7 @@ func handler(w http.ResponseWriter, req *http.Request) {
fmt.Fprintf(w, "%v: %v\n", name, h)
}
}
if showEnvs == "1" || strings.ToLower(showEnvs) == "yes" || strings.ToLower(showEnvs) == "true" {
if strings.ToLower(showEnvs) == "true" || strings.ToLower(showEnvs) == "yes" || strings.ToLower(showEnvs) == "on" || showEnvs == "1" {
fmt.Fprintln(w)
fmt.Fprintf(w, "Env variables:\n")
for _, e := range os.Environ() {
@@ -54,7 +59,7 @@ func handler(w http.ResponseWriter, req *http.Request) {
}
func main() {
fmt.Printf("[%v] - %v - YoSoy is up!\n", hostname, time.Now().Format(time.RFC3339))
fmt.Printf("[%v] - %v - yosoy is up!\n", hostname, time.Now().Format(time.RFC3339))
http.HandleFunc("/", handler)
http.ListenAndServe(":80", nil)
}