updated port >1024

implemented support for custom timeout parameter for ping/reachability analyzer

.github/FUNDING.yml

@@ -0,0 +1,3 @@
+# These are supported funding model platforms
+
+github: [lukaszbudnik]

.github/dependabot.yml

@@ -0,0 +1,17 @@
+version: 2
+updates:
+  # Maintain dependencies for GitHub Actions
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
+  # Maintain dependencies for go lang
+  - package-ecosystem: "gomod"
+    directory: "/"
+    schedule:
+      interval: "daily"
+  # Maintain dependencies for docker
+  - package-ecosystem: "docker"
+    directory: "/"
+    schedule:
+      interval: "daily"

.github/workflows/docker-image.yml

@@ -0,0 +1,26 @@
+name: Docker Image CI
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4.1.1
+      - name: Build the Docker image
+        run: docker build . --file Dockerfile --tag yosoy-local:latest
+      - name: Run simple integration test
+        run: |
+          docker run -p 3333:80 yosoy-local:latest > yosoy.log &
+          sleep 5
+          RESULT=$(curl -s -X DELETE -H 'x-api-key: abc123' 'http://0.0.0.0:3333/sample/path?with=params')
+          echo "$RESULT"
+          if [[ $RESULT =~ '"method":"DELETE"' ]]
+          then
+            echo 'Test successful'
+            exit 0
+          else
+            echo 'Test failure'
+            exit 1
+          fi

.github/workflows/docker-publish.yml

@@ -0,0 +1,52 @@
+name: Publish Docker image
+
+on:
+  push:
+    branches: [main]
+  release:
+    types: [published]
+
+jobs:
+  push_to_registries:
+    name: Push Docker image to Docker Hub and ghcr.io registries
+    runs-on: ubuntu-latest
+    permissions:
+      packages: write
+      contents: read
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@v4.1.1
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKER_HUB_USERNAME }}
+          password: ${{ secrets.DOCKER_HUB_TOKEN }}
+
+      - name: Log in to the Container registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: |
+            lukasz/yosoy
+            ghcr.io/${{ github.repository }}
+          tags: |
+            type=edge
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+
+      - name: Build and push Docker images
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

.github/workflows/go.yml

@@ -0,0 +1,20 @@
+name: Go
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4.1.1
+
+      - name: Set up Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: 1.19
+
+      - name: Build
+        run: go build -v ./...
+
+      - name: Test
+        run: go test -v ./...

.gitignore

@@ -0,0 +1,3 @@
+debug.test
+cover.out
+yosoy

Dockerfile

@@ -1,16 +1,19 @@
-FROM golang:1.13.5-alpine3.10 as builder
+FROM golang:1.21-alpine as builder
 
 LABEL maintainer="Łukasz Budnik lukasz.budnik@gmail.com"
 
+# install prerequisites
+RUN apk update && apk add git
+
 # build yosoy
-RUN apk add git
-RUN git clone https://github.com/lukaszbudnik/yosoy.git
+ADD . /go/yosoy
+RUN go env -w GOPROXY=direct
 RUN cd /go/yosoy && go build
 
-FROM alpine:3.10
+FROM alpine:3.18
 COPY --from=builder /go/yosoy/yosoy /bin
 
 # register entrypoint
 ENTRYPOINT ["yosoy"]
 
-EXPOSE 80
+EXPOSE 8080

README.md

@@ -1,151 +1,197 @@
-# yosoy
+# yosoy ![Go](https://github.com/lukaszbudnik/yosoy/workflows/Go/badge.svg) ![Docker](https://github.com/lukaszbudnik/yosoy/workflows/Docker%20Image%20CI/badge.svg)
 
-yosoy is a HTTP service for stubbing and prototyping 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 an HTTP service for stubbing and prototyping distributed applications. It is a service that introduces itself to the caller and prints useful information about its runtime environment. 
 
-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 is extremely useful when creating a stub for a distributed application, as it provides more meaningful responses than, for example, a default nginx welcome page. Further, yosoy incorporates a built-in reachability analyzer to facilitate troubleshooting connectivity issues in distributed systems. A dedicated reachability analyzer endpoint validates network connectivity between yosoy and remote endpoints.
 
 Typical use cases include:
 
-* testing HTTP routing & ingress
-* testing HTTP load balancing
-* testing HTTP caching
-* stubbing and prototyping distributed applications
+- Testing HTTP routing and ingress
+- Testing HTTP load balancing
+- Testing HTTP caching
+- Executing reachability analysis
+- Stubbing and prototyping distributed applications
 
-yosoy will provide information like:
+"Yo soy" means "I am" in Spanish.
 
-* 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
+## API
 
-See [Kubernetes example](#kubernetes-example) below.
+yosoy responds to all requests with a JSON containing the information about:
 
+- HTTP request:
+  - Host
+  - Request URI
+  - Method
+  - Scheme
+  - Proto
+  - URL
+  - Remote IP
+  - HTTP headers
+  - HTTP proxy headers
+- host:
+  - Hostname
+  - How many times it was called
+  - 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
+
+Check [Sample JSON response](#sample-json-response) to see how you can use yosoy for stubbing/prototyping/troubleshooting distributed applications.
+
+## ping/reachability analyzer
+
+yosoy includes a simple ping/reachability analyzer. You can use this functionality when prototyping distributed systems to validate whether a given component can reach a specific endpoint. yosoy exposes a dedicated `/_/yosoy/ping` endpoint which accepts the following 4 query parameters:
+
+* `h` - required - hostname of the endpoint
+* `p` - required - port of the endpoint
+* `n` - optional - network, all valid Go networks are supported (including the most popular ones like `tcp`, `udp`, IPv4, IPV6, etc.). If `n` parameter is not provided, it defaults to `tcp`. If `n` parameter is set to unknown network, an error will be returned.
+* `t` - optional - timeout in seconds. If `t` parameter is not provided, it defaults to `10`. If `t` contains invalid integer literal, an error will be returned.
+
+Check [Sample ping/reachability analyzer responses](#sample-pingreachability-analyzer-responses) to see how you can use yosoy for troubleshooting network connectivity.
 
 ## Docker image
 
-The docker image is available on docker hub:
+The docker image is available on docker hub and ghcr.io:
 
-```
-lukasz/yosoy
+```sh
+docker pull lukasz/yosoy
+docker pull ghcr.io/lukaszbudnik/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`.
+There is a sample Kubernetes deployment file in the `test` folder. It uses both `YOSOY_SHOW_ENVS` and `YOSOY_SHOW_FILES` features. The deployment uses Kubernetes Downward API to expose labels and annotations as volume files which are then returned by yosoy.
 
-> To illustrate `YOSOY_SHOW_FILES` functionality Kubernetes Downward API is used to expose labels and annotations as volume files which are then returned by yosoy.
+Deploy it to minikube and execute curl to the service a couple of times:
 
-```
-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
----
-apiVersion: v1
-kind: Service
-metadata:
-  name: camarero
-  labels:
-    app.kubernetes.io/name: camarero
-spec:
-  type: NodePort
-  selector:
-    app.kubernetes.io/name: camarero
-  ports:
-    - protocol: TCP
-      port: 80
+```bash
+# start minikube
+minikube start
+# deploy test service
+kubectl apply -f test/deployment.yaml
+# tunnel to it and copy the URL as $URL variable
+minikube service --url camarero
+# simulate some HTTP requests
+curl -H "Host: gateway.myapp.com" $URL/camarero/abc
+curl -H "Host: gateway.myapp.com" $URL/camarero/abc
+curl -H "Host: gateway.myapp.com" $URL/camarero/abc
+curl -H "Host: gateway.myapp.com" $URL/camarero/abc
 ```
 
-Deploy above service (with 2 replicas) and execute curl to the service a couple of times:
+## Sample JSON response
 
-```
-kubectl apply -f test-deployment.yaml
-export NODE_PORT=$(kubectl get services/camarero -o go-template='{{(index .spec.ports 0).nodePort}}')
-curl $(minikube ip):$NODE_PORT
-curl $(minikube ip):$NODE_PORT
-curl $(minikube ip):$NODE_PORT
-curl $(minikube ip):$NODE_PORT
+A sample yosoy JSON response to a request made from a single page application (SPA) to a backend API deployed in Kubernetes behind nginx ingress and [haproxy-auth-gateway](https://github.com/lukaszbudnik/haproxy-auth-gateway) looks like this:
+
+```json
+{
+  "host": "api.localtest.me",
+  "proto": "HTTP/1.1",
+  "method": "GET",
+  "scheme": "https",
+  "requestUri": "/camarero",
+  "url": "https:///camarero",
+  "remoteAddr": "192.168.65.3",
+  "counter": 1,
+  "headers": {
+    "Accept": ["*/*"],
+    "Accept-Encoding": ["gzip, deflate, br"],
+    "Accept-Language": ["en-US,en;q=0.9,pl-PL;q=0.8,pl;q=0.7,es;q=0.6"],
+    "Authorization": [
+      "Bearer eyJhbGciOiJSUzI1NiIsInR5cCIgOiAiSldUIiwia2lkIiA6ICJXejFuaDNCWDI4UHMxVEMzSDRoOW52Q1VWRXpjVVBzQms4Z1NmeEp4ZS1JIn0.eyJleHAiOjE2Mjk4MjM3OTMsImlhdCI6MTYyOTgyMjg5MywiYXV0aF90aW1lIjoxNjI5ODIyODkyLCJqdGkiOiI3ZmQzMjkwZi05NjMyLTQ0NzEtYjRjOS1lNTFjZDYwMjllYjgiLCJpc3MiOiJodHRwczovL2F1dGgubG9jYWx0ZXN0Lm1lL2F1dGgvcmVhbG1zL2hvdGVsIiwic3ViIjoiMDdmYzM3YmYtMmJjNy00ZTRmLWE3MDUtYzRjNjgzNTIwYmU1IiwidHlwIjoiQmVhcmVyIiwiYXpwIjoicmVhY3QiLCJub25jZSI6IjQzNDhmMjU5LTliYTYtNDk2ZC04N2I5LWZmZGYzNDMwN2UzOSIsInNlc3Npb25fc3RhdGUiOiJmNTM5OGI3Ny01OTNhLTQ3OWYtOTc5NS00NGIyNGJjMjhkYjQiLCJhY3IiOiIxIiwiYWxsb3dlZC1vcmlnaW5zIjpbImh0dHBzOi8vbHVrYXN6YnVkbmlrLmdpdGh1Yi5pbyJdLCJyZWFsbV9hY2Nlc3MiOnsicm9sZXMiOlsiY2FtYXJlcm8iXX0sInNjb3BlIjoib3BlbmlkIGVtYWlsIHByb2ZpbGUiLCJzaWQiOiJmNTM5OGI3Ny01OTNhLTQ3OWYtOTc5NS00NGIyNGJjMjhkYjQiLCJlbWFpbF92ZXJpZmllZCI6ZmFsc2UsIm5hbWUiOiJKdWxpbyIsInByZWZlcnJlZF91c2VybmFtZSI6Imp1bGlvIiwiZ2l2ZW5fbmFtZSI6Ikp1bGlvIn0.t5y3L4FzGxM0zwI3fskDI8Kemxz_izcvPPKciSEvNHnZWGQK-9AclGNFz_A9cLFSkpc6l6lBmt7WaC0i04c4h1a9G9AOFImmVXPMPDdTXOQ4aah4CvlN6Fy8ShvSHrQA-wMHEELBpIFsKFx2WP3QHiy27ycr3kqQzW4QymyU7J8tM4-qKR_H1_8aiNOrm5fIED-nEP096V2zvWXiGZX7ts6XE2-annhKphCABLdmIiwgDUnhlAz0hdiDrDbIjzr0ldW4AnUkSQxIZY0PnoEnGVuUvkOYvJpFx10gjORMnRgHSEj9Mk5dtyVGHcihZ5TntCL40WoymNxae6K4-FH3Lw"
+    ],
+    "Origin": ["https://lukaszbudnik.github.io"],
+    "Referer": ["https://lukaszbudnik.github.io/"],
+    "Sec-Ch-Ua": [
+      "\" Not;A Brand\";v=\"99\", \"Google Chrome\";v=\"91\", \"Chromium\";v=\"91\""
+    ],
+    "Sec-Ch-Ua-Mobile": ["?0"],
+    "Sec-Fetch-Dest": ["empty"],
+    "Sec-Fetch-Mode": ["cors"],
+    "Sec-Fetch-Site": ["cross-site"],
+    "User-Agent": [
+      "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36"
+    ],
+    "X-Forwarded-For": ["192.168.65.3", "10.1.3.9"],
+    "X-Forwarded-Host": ["api.localtest.me"],
+    "X-Forwarded-Port": ["443"],
+    "X-Forwarded-Proto": ["https"],
+    "X-Real-Ip": ["192.168.65.3"],
+    "X-Request-Id": ["48a77564d88ca8a893610b9458bfd885"],
+    "X-Scheme": ["https"]
+  },
+  "hostname": "camarero-cf7c95ccd-cz5lh",
+  "envVariables": [
+    "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
+    "HOSTNAME=camarero-cf7c95ccd-cz5lh",
+    "YOSOY_SHOW_FILES=/etc/podinfo/labels,/etc/podinfo/annotations",
+    "YOSOY_SHOW_ENVS=true",
+    "KUBERNETES_SERVICE_PORT=443",
+    "KUBERNETES_PORT_443_TCP=tcp://10.96.0.1:443",
+    "KUBERNETES_PORT=tcp://10.96.0.1:443",
+    "KUBERNETES_PORT_443_TCP_PORT=443",
+    "KUBERNETES_SERVICE_HOST=10.96.0.1",
+    "KUBERNETES_PORT_443_TCP_PROTO=tcp",
+    "KUBERNETES_PORT_443_TCP_ADDR=10.96.0.1",
+    "HOME=/root"
+  ],
+  "files": {
+    "/etc/podinfo/annotations": "kubernetes.io/config.seen=\"2021-08-24T15:12:19.555374430Z\"\nkubernetes.io/config.source=\"api\"",
+    "/etc/podinfo/labels": "app.kubernetes.io/component=\"api\"\napp.kubernetes.io/name=\"camarero\"\napp.kubernetes.io/part-of=\"hotel\"\napp.kubernetes.io/version=\"0.0.1\"\npod-template-hash=\"cf7c95ccd\""
+  }
+}
 ```
 
-A sample response looks like this:
+## Sample ping/reachability analyzer responses
 
+To test if yosoy can connect to `google.com` on port `443` using default `tcp` network use the following command:
+
+```bash
+curl -v "http://localhost/_/yosoy/ping?h=google.com&p=443"
+> GET /_/yosoy/ping?h=google.com&p=443 HTTP/1.1
+> Host: localhost
+> User-Agent: curl/7.86.0
+> Accept: */*
+>
+< HTTP/1.1 200 OK
+< Date: Fri, 17 Nov 2023 05:54:36 GMT
+< Content-Length: 29
+< Content-Type: text/plain; charset=utf-8
+<
+{"message":"ping succeeded"}
 ```
-Request URI: /
-Hostname: camarero-859d7c6d6b-kb5s5
-Remote IP: 172.18.0.1
-Called: 2
 
-HTTP headers:
-Accept: */*
-User-Agent: curl/7.64.1
+To see an unsuccessful response you may use localhost with some random port number:
 
-Env variables:
-PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
-HOSTNAME=camarero-859d7c6d6b-kb5s5
-YOSOY_SHOW_ENVS=true
-YOSOY_SHOW_FILES=/etc/podinfo/labels,/etc/podinfo/annotations
-CAMARERO_PORT_80_TCP_PORT=80
-CAMARERO_PORT_80_TCP_ADDR=10.105.203.131
-KUBERNETES_PORT=tcp://10.96.0.1:443
-KUBERNETES_PORT_443_TCP_PORT=443
-CAMARERO_SERVICE_HOST=10.105.203.131
-KUBERNETES_PORT_443_TCP_PROTO=tcp
-KUBERNETES_SERVICE_HOST=10.96.0.1
-KUBERNETES_SERVICE_PORT=443
-KUBERNETES_SERVICE_PORT_HTTPS=443
-KUBERNETES_PORT_443_TCP=tcp://10.96.0.1:443
-KUBERNETES_PORT_443_TCP_ADDR=10.96.0.1
-CAMARERO_PORT=tcp://10.105.203.131:80
-CAMARERO_SERVICE_PORT=80
-CAMARERO_PORT_80_TCP=tcp://10.105.203.131:80
-CAMARERO_PORT_80_TCP_PROTO=tcp
-HOME=/root
-
-File /etc/podinfo/labels:
-app.kubernetes.io/name="camarero"
-pod-template-hash="859d7c6d6b"
-
-File /etc/podinfo/annotations:
-kubernetes.io/config.seen="2020-11-17T07:38:15.374049163Z"
-kubernetes.io/config.source="api"
+```bash
+curl -v "http://localhost/_/yosoy/ping?h=127.0.0.1&p=12345"
+> GET /_/yosoy/ping?h=127.0.0.1&p=12345 HTTP/1.1
+> Host: localhost
+> User-Agent: curl/7.86.0
+> Accept: */*
+>
+< HTTP/1.1 500 Internal Server Error
+< Date: Fri, 17 Nov 2023 05:53:48 GMT
+< Content-Length: 66
+< Content-Type: text/plain; charset=utf-8
+<
+{"error":"dial tcp 127.0.0.1:12345: connect: connection refused"}
 ```
+
+## Building and testing locally
+
+Here are some commands to get you started.
+
+Run yosoy directly on port 80.
+
+```bash
+go test -coverprofile cover.out
+go tool cover -html=cover.out
+go run server.go
+```
+
+Building local Docker container and run it on port 8080:
+
+```bash
+docker build -t yosoy-local:latest .
+docker run --rm --name yosoy-local -p 8080:80 yosoy-local:latest
+```

go.mod

@@ -0,0 +1,16 @@
+module github.com/lukaszbudnik/yosoy
+
+go 1.21
+
+require (
+	github.com/gorilla/handlers v1.5.2
+	github.com/gorilla/mux v1.8.1
+	github.com/stretchr/testify v1.8.4
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/felixge/httpsnoop v1.0.3 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,16 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/felixge/httpsnoop v1.0.3 h1:s/nj+GCswXYzN5v2DpNMuMQYe+0DDwt5WVCU6CWBdXk=
+github.com/felixge/httpsnoop v1.0.3/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
+github.com/gorilla/handlers v1.5.2 h1:cLTUSsNkgcwhgRqvCNmdbRWG0A3N4F+M2nWKdScwyEE=
+github.com/gorilla/handlers v1.5.2/go.mod h1:dX+xVpaxdSw+q0Qek8SSsl3dfMk3jNddUkMzo0GtH0w=
+github.com/gorilla/mux v1.8.1 h1:TuBL49tXwgrFYWhqrNgrUNEY92u81SPhu7sTdzQEiWY=
+github.com/gorilla/mux v1.8.1/go.mod h1:AKf9I4AEqPTmMytcMc0KkNouC66V3BtZ4qD5fmWSiMQ=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

server.go

@@ -1,76 +1,192 @@
 package main
 
 import (
-	"fmt"
-	"io/ioutil"
+	"encoding/json"
+	"log"
+	"net"
 	"net/http"
 	"os"
-	"sort"
+	"strconv"
 	"strings"
 	"time"
+
+	"github.com/gorilla/handlers"
+	"github.com/gorilla/mux"
 )
 
+const PING_DEFAULT_TIMEOUT = 10
+const PING_DEFAULT_NETWORK = "tcp"
+
+type response struct {
+	Host         string              `json:"host"`
+	Proto        string              `json:"proto"`
+	Method       string              `json:"method"`
+	Scheme       string              `json:"scheme"`
+	RequestURI   string              `json:"requestUri"`
+	URL          string              `json:"url"`
+	RemoteAddr   string              `json:"remoteAddr"`
+	Counter      int                 `json:"counter"`
+	Headers      map[string][]string `json:"headers"`
+	Hostname     string              `json:"hostname"`
+	EnvVariables []string            `json:"envVariables,omitempty"`
+	Files        map[string]string   `json:"files,omitempty"`
+}
+
+type errorResponse struct {
+	Error string `json:"error"`
+}
+
+type successResponse struct {
+	Message string `json:"message"`
+}
+
 var counter = 0
 var hostname = os.Getenv("HOSTNAME")
-var showEnvs = os.Getenv("YOSOY_SHOW_ENVS")
-var showFiles = os.Getenv("YOSOY_SHOW_FILES")
+
+func preflight(w http.ResponseWriter, req *http.Request) {
+	w.Header().Set("Access-Control-Allow-Origin", "*")
+	w.Header().Set("Access-Control-Allow-Methods", "*")
+	w.Header().Set("Access-Control-Allow-Headers", "*")
+	w.Header().Set("Access-Control-Allow-Credentials", "true")
+	w.Header().Set("Access-Control-Expose-Headers", "*")
+	w.Header().Set("Access-Control-Max-Age", "600")
+	w.WriteHeader(http.StatusOK)
+}
 
 func handler(w http.ResponseWriter, req *http.Request) {
-	if req.RequestURI == "/favicon.ico" {
-		w.WriteHeader(http.StatusNotFound)
-		return
+	w.Header().Set("Access-Control-Allow-Origin", "*")
+
+	showEnvs := os.Getenv("YOSOY_SHOW_ENVS")
+	showFiles := os.Getenv("YOSOY_SHOW_FILES")
+
+	response := &response{}
+
+	counter++
+	response.Counter = counter
+
+	remoteAddr := remoteAddrWithoutPort(req)
+	response.RemoteAddr = remoteAddr
+
+	response.RequestURI = req.RequestURI
+	response.Host = req.Host
+	response.Proto = req.Proto
+	response.Method = req.Method
+	response.Scheme = req.URL.Scheme
+	response.Headers = req.Header
+	response.URL = req.URL.String()
+
+	response.Hostname = hostname
+
+	if strings.ToLower(showEnvs) == "true" || strings.ToLower(showEnvs) == "yes" || strings.ToLower(showEnvs) == "on" || showEnvs == "1" {
+		response.EnvVariables = os.Environ()
+	}
+	if len(showFiles) > 0 {
+		response.Files = make(map[string]string)
+		files := strings.Split(showFiles, ",")
+		for _, file := range files {
+			bytes, err := os.ReadFile(file)
+			if err != nil {
+				log.Printf("Could not read file %v: %v\n", file, err)
+				continue
+			}
+			contents := string(bytes)
+			response.Files[file] = contents
+		}
 	}
 
+	w.Header().Add("Content-Type", "application/json; charset=utf-8")
+	w.WriteHeader(http.StatusOK)
+	json.NewEncoder(w).Encode(response)
+}
+
+func ping(w http.ResponseWriter, req *http.Request) {
+	// get h, p, n, t parameters from query string
+	hostname := req.URL.Query().Get("h")
+	port := req.URL.Query().Get("p")
+	network := req.URL.Query().Get("n")
+	timeoutString := req.URL.Query().Get("t")
+	var timeout int64 = PING_DEFAULT_TIMEOUT
+
+	// return HTTP BadRequest when hostname is empty
+	if hostname == "" {
+		w.WriteHeader(http.StatusBadRequest)
+		w.Header().Add("Content-Type", "application/json; charset=utf-8")
+		json.NewEncoder(w).Encode(&errorResponse{"hostname is empty"})
+		return
+	}
+	// return HTTP BadRequest when port is empty
+	if port == "" {
+		w.WriteHeader(http.StatusBadRequest)
+		w.Header().Add("Content-Type", "application/json; charset=utf-8")
+		json.NewEncoder(w).Encode(&errorResponse{"port is empty"})
+		return
+	}
+	// check if timeoutString is a valid int64, return HTTP BadRequest when invalid, otherwise set timeout value
+	if timeoutString != "" {
+		timeoutInt, err := strconv.ParseInt(timeoutString, 10, 64)
+		if err != nil {
+			w.WriteHeader(http.StatusBadRequest)
+			w.Header().Add("Content-Type", "application/json; charset=utf-8")
+			json.NewEncoder(w).Encode(&errorResponse{"timeout is invalid"})
+			return
+		}
+		timeout = timeoutInt
+	}
+
+	// if network is empty set default to tcp
+	if network == "" {
+		network = PING_DEFAULT_NETWORK
+	}
+
+	// ping the hostname and port
+	err := pingHost(hostname, port, network, timeout)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Header().Add("Content-Type", "application/json; charset=utf-8")
+		json.NewEncoder(w).Encode(&errorResponse{err.Error()})
+		return
+	}
+	// return HTTP OK
+	w.WriteHeader(http.StatusOK)
+	w.Header().Add("Content-Type", "application/json; charset=utf-8")
+	json.NewEncoder(w).Encode(&successResponse{"ping succeeded"})
+}
+
+func pingHost(hostname, port, network string, timeout int64) error {
+	// create timeoutDuration variable of Duration type using timeout as the value in seconds
+	timeoutDuration := time.Duration(timeout) * time.Second
+
+	// open a socket to hostname and port
+	conn, err := net.DialTimeout(network, hostname+":"+port, timeoutDuration)
+	if err != nil {
+		return err
+	}
+	// close the socket
+	conn.Close()
+	return nil
+}
+
+func remoteAddrWithoutPort(req *http.Request) string {
 	remoteAddr := req.RemoteAddr
 	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(http.StatusOK)
-	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", remoteAddr)
-	counter++
-	fmt.Fprintf(w, "Called: %v\n", counter)
-	fmt.Fprintln(w)
-	fmt.Fprintf(w, "HTTP headers:\n")
-	headers := make([]string, 0, len(req.Header))
-	for k := range req.Header {
-		headers = append(headers, k)
-	}
-	sort.Strings(headers)
-	for _, header := range headers {
-		headers := req.Header[header]
-		for _, h := range headers {
-			fmt.Fprintf(w, "%v: %v\n", header, h)
-		}
-	}
-	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() {
-			fmt.Fprintln(w, e)
-		}
-	}
-	if len(showFiles) > 0 {
-		files := strings.Split(showFiles, ",")
-		for _, file := range files {
-			bytes, err := ioutil.ReadFile(file)
-			if err != nil {
-				fmt.Printf("[%v] - %v - could not read file %v: %v\n", hostname, time.Now().Format(time.RFC3339), file, err)
-				continue
-			}
-			fmt.Fprintln(w)
-			fmt.Fprintf(w, "File %v:\n", file)
-			contents := string(bytes)
-			fmt.Fprintln(w, contents)
-		}
-	}
+	return remoteAddr
 }
 
 func main() {
-	fmt.Printf("[%v] - %v - yosoy is up!\n", hostname, time.Now().Format(time.RFC3339))
-	http.HandleFunc("/", handler)
-	http.ListenAndServe(":80", nil)
+	log.Printf("yosoy is up %v\n", hostname)
+
+	r := mux.NewRouter()
+
+	r.Handle("/favicon.ico", r.NotFoundHandler)
+	r.HandleFunc("/_/yosoy/ping", ping).Methods(http.MethodGet)
+	r.PathPrefix("/").HandlerFunc(preflight).Methods(http.MethodOptions)
+	r.PathPrefix("/").HandlerFunc(handler).Methods(http.MethodGet, http.MethodPut, http.MethodPatch, http.MethodPost, http.MethodDelete, http.MethodConnect, http.MethodHead, http.MethodTrace)
+
+	loggingRouter := handlers.CombinedLoggingHandler(os.Stdout, r)
+	proxyRouter := handlers.ProxyHeaders(loggingRouter)
+	recoveryRouter := handlers.RecoveryHandler()(proxyRouter)
+
+	http.ListenAndServe(":8080", recoveryRouter)
 }

server_test.go

@@ -0,0 +1,305 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestHandler(t *testing.T) {
+	os.Setenv("YOSOY_SHOW_ENVS", "true")
+	os.Setenv("YOSOY_SHOW_FILES", ".gitignore,/file/does/not/exist")
+
+	req, err := http.NewRequest("GET", "https://example.org/sample/path?one=jeden&two=dwa", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req.Header.Set("Accept", "*/*")
+
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(handler)
+
+	handler.ServeHTTP(rr, req)
+
+	if status := rr.Code; status != http.StatusOK {
+		t.Errorf("handler returned wrong status code: got %v want %v", status, http.StatusOK)
+	}
+
+	result := rr.Result()
+	buf := new(bytes.Buffer)
+	buf.ReadFrom(result.Body)
+
+	var response response
+	json.Unmarshal(buf.Bytes(), &response)
+
+	// test response
+	assert.Equal(t, 1, response.Counter)
+	assert.Equal(t, "example.org", response.Host)
+	assert.Equal(t, "GET", response.Method)
+	assert.Equal(t, "https", response.Scheme)
+	assert.Equal(t, "HTTP/1.1", response.Proto)
+	assert.Equal(t, "https://example.org/sample/path?one=jeden&two=dwa", response.URL)
+	assert.NotEmpty(t, response.EnvVariables)
+	assert.NotEmpty(t, response.Files[".gitignore"])
+
+	// test cors
+	assert.Contains(t, result.Header["Access-Control-Allow-Origin"], "*")
+}
+
+// write test for request /_/yosoy/ping without any query parameters, the request should return bad request 400 error and return JSON error about missing hostname parameter
+func TestHandlerPingNoParameters(t *testing.T) {
+	req, err := http.NewRequest("GET", "https://example.org/_/yosoy/ping", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req.Header.Set("Accept", "*/*")
+
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(ping)
+
+	handler.ServeHTTP(rr, req)
+
+	if status := rr.Code; status != http.StatusBadRequest {
+		t.Errorf("handler returned wrong status code: got %v want %v", status, http.StatusBadRequest)
+	}
+
+	result := rr.Result()
+	buf := new(bytes.Buffer)
+	buf.ReadFrom(result.Body)
+
+	var response errorResponse
+	json.Unmarshal(buf.Bytes(), &response)
+
+	// test response
+	assert.Equal(t, "hostname is empty", response.Error)
+}
+
+// write test for request /_/yosoy/ping with h parameter, the request should return bad request 400 error and return JSON error about port is empty
+func TestHandlerPingWithHostname(t *testing.T) {
+	req, err := http.NewRequest("GET", "https://example.org/_/yosoy/ping?h=example.org", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req.Header.Set("Accept", "*/*")
+
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(ping)
+
+	handler.ServeHTTP(rr, req)
+
+	if status := rr.Code; status != http.StatusBadRequest {
+		t.Errorf("handler returned wrong status code: got %v want %v", status, http.StatusBadRequest)
+	}
+
+	result := rr.Result()
+	buf := new(bytes.Buffer)
+	buf.ReadFrom(result.Body)
+
+	var response errorResponse
+	json.Unmarshal(buf.Bytes(), &response)
+
+	// test response
+	assert.Equal(t, "port is empty", response.Error)
+}
+
+// write test for request /_/yosoy/ping with h=127.0.0.1 parameter and p=8123 parameter, the request should return bad request 400 error and return JSON error about tcp connection issue
+func TestHandlerPingWithHostnameAndPort(t *testing.T) {
+	req, err := http.NewRequest("GET", "https://example.org/_/yosoy/ping?h=127.0.0.1&p=8123", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req.Header.Set("Accept", "*/*")
+
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(ping)
+
+	handler.ServeHTTP(rr, req)
+
+	if status := rr.Code; status != http.StatusInternalServerError {
+		t.Errorf("handler returned wrong status code: got %v want %v", status, http.StatusInternalServerError)
+	}
+
+	result := rr.Result()
+	buf := new(bytes.Buffer)
+	buf.ReadFrom(result.Body)
+
+	var response errorResponse
+	json.Unmarshal(buf.Bytes(), &response)
+
+	// test response
+	assert.Equal(t, "dial tcp 127.0.0.1:8123: connect: connection refused", response.Error)
+}
+
+// write test for request /_/yosoy/ping with h=127.0.0.1 parameter and p=8123 parameter, the request should return 200 ok and return JSON with message ping succeeded
+func TestHandlerPingWithHostnameAndPortSuccess(t *testing.T) {
+
+	// create tcp process to listen on port 8123
+	listener, err := net.Listen("tcp", "localhost:8123")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer listener.Close()
+
+	req, err := http.NewRequest("GET", "https://example.org/_/yosoy/ping?h=127.0.0.1&p=8123", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req.Header.Set("Accept", "*/*")
+
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(ping)
+
+	handler.ServeHTTP(rr, req)
+
+	if status := rr.Code; status != http.StatusOK {
+		t.Errorf("handler returned wrong status code: got %v want %v", status, http.StatusOK)
+	}
+
+	result := rr.Result()
+	buf := new(bytes.Buffer)
+	buf.ReadFrom(result.Body)
+
+	var response successResponse
+	json.Unmarshal(buf.Bytes(), &response)
+
+	// test response
+	assert.Equal(t, "ping succeeded", response.Message)
+}
+
+// write test for request /_/yosoy/ping?h=127.0.0.1&p=8123&n=qwq, the request should return 500 internal server error and return JSON with error "dial qwq: unknown network qwq"
+func TestHandlerPingWithHostnameAndPortAndNetwork(t *testing.T) {
+
+	// create tcp process to listen on port 8123
+	listener, err := net.Listen("tcp", "localhost:8123")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer listener.Close()
+
+	req, err := http.NewRequest("GET", "https://example.org/_/yosoy/ping?h=127.0.0.1&p=8123&n=qwq", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req.Header.Set("Accept", "*/*")
+
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(ping)
+
+	handler.ServeHTTP(rr, req)
+
+	if status := rr.Code; status != http.StatusInternalServerError {
+		t.Errorf("handler returned wrong status code: got %v want %v", status, http.StatusInternalServerError)
+	}
+
+	result := rr.Result()
+	buf := new(bytes.Buffer)
+	buf.ReadFrom(result.Body)
+	var response errorResponse
+	json.Unmarshal(buf.Bytes(), &response)
+	// test response
+	assert.Equal(t, "dial qwq: unknown network qwq", response.Error)
+}
+
+// write test for preflight HTTP Options request, verify that all headers are set
+func TestHandlerPreflight(t *testing.T) {
+	req, err := http.NewRequest("OPTIONS", "https://example.org/test", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req.Header.Set("Accept", "*/*")
+
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(preflight)
+
+	handler.ServeHTTP(rr, req)
+
+	if status := rr.Code; status != http.StatusOK {
+		t.Errorf("handler returned wrong status code: got %v want %v", status, http.StatusOK)
+	}
+
+	result := rr.Result()
+	buf := new(bytes.Buffer)
+	buf.ReadFrom(result.Body)
+
+	// test response
+	assert.Equal(t, "*", result.Header.Get("Access-Control-Allow-Origin"))
+	assert.Equal(t, "*", result.Header.Get("Access-Control-Allow-Methods"))
+	assert.Equal(t, "*", result.Header.Get("Access-Control-Allow-Headers"))
+	assert.Equal(t, "true", result.Header.Get("Access-Control-Allow-Credentials"))
+	assert.Equal(t, "600", result.Header.Get("Access-Control-Max-Age"))
+	assert.Equal(t, "*", result.Header.Get("Access-Control-Expose-Headers"))
+}
+
+// write test for request /_/yosoy/ping?h=127.0.0.1&p=8123&n=tcp&t=5, the request should return 200 ok and return JSON with message "ping succeeded"
+func TestHandlerPingWithHostnameAndPortAndNetworkAndTimeout(t *testing.T) {
+
+	// create tcp process to listen on port 8123
+	listener, err := net.Listen("tcp", "localhost:8123")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer listener.Close()
+
+	req, err := http.NewRequest("GET", "https://example.org/_/yosoy/ping?h=127.0.0.1&p=8123&n=tcp&t=5", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req.Header.Set("Accept", "*/*")
+
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(ping)
+
+	handler.ServeHTTP(rr, req)
+
+	if status := rr.Code; status != http.StatusOK {
+		t.Errorf("handler returned wrong status code: got %v want %v", status, http.StatusOK)
+	}
+
+	result := rr.Result()
+	buf := new(bytes.Buffer)
+	buf.ReadFrom(result.Body)
+	var response successResponse
+	json.Unmarshal(buf.Bytes(), &response)
+	// test response
+	assert.Equal(t, "ping succeeded", response.Message)
+}
+
+// write test for request /_/yosoy/ping?h=127.0.0.1&p=8123&n=tcp&t=invalid, the request should return 400 bad request and return JSON with error "timeout is invalid"
+func TestHandlerPingWithHostnameAndPortAndNetworkAndTimeoutInvalid(t *testing.T) {
+
+	// create tcp process to listen on port 8123
+	listener, err := net.Listen("tcp", "localhost:8123")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer listener.Close()
+
+	req, err := http.NewRequest("GET", "https://example.org/_/yosoy/ping?h=127.0.0.1&p=8123&n=tcp&t=invalid", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req.Header.Set("Accept", "*/*")
+
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(ping)
+
+	handler.ServeHTTP(rr, req)
+
+	if status := rr.Code; status != http.StatusBadRequest {
+		t.Errorf("handler returned wrong status code: got %v want %v", status, http.StatusBadRequest)
+	}
+
+	result := rr.Result()
+	buf := new(bytes.Buffer)
+	buf.ReadFrom(result.Body)
+	var response errorResponse
+	json.Unmarshal(buf.Bytes(), &response)
+	// test response
+	assert.Equal(t, "timeout is invalid", response.Error)
+}

test/deployment.yaml

@@ -0,0 +1,53 @@
+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:edge
+        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
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: camarero
+  labels:
+    app.kubernetes.io/name: camarero
+spec:
+  type: NodePort
+  selector:
+    app.kubernetes.io/name: camarero
+  ports:
+    - protocol: TCP
+      port: 80