implemented support for custom timeout parameter for ping/reachabilit…

…y analyzer

README.md

@@ -36,7 +36,16 @@ yosoy responds to all requests with a JSON containing the information about:
 
 Check [Sample JSON response](#sample-json-response) to see how you can use yosoy for stubbing/prototyping/troubleshooting distributed applications.
 
-Check [ping/reachability analyzer](#pingreachability-analyzer) to see how you can use yosoy for troubleshooting network connectivity.
+## 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
 
@@ -132,24 +141,40 @@ A sample yosoy JSON response to a request made from a single page application (S
 }
 ```
 
-## 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 3 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`. Go will throw an error if `n` parameter will be set to unknown network.
+## Sample ping/reachability analyzer responses
 
-For example, to test if yosoy can connect to `google.com` on port `443` using default `tcp` network use the following command:
+To test if yosoy can connect to `google.com` on port `443` using default `tcp` network use the following command:
 
 ```bash
-curl "$URL/_/yosoy/ping?h=google.com&p=443"
+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"}
 ```
 
 To see an unsuccessful response you may use localhost with some random port number:
 
 ```bash
-curl "$URL/_/yosoy/ping?h=127.0.0.1&p=12345"
+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

server.go

@@ -6,12 +6,17 @@ import (
 	"net"
 	"net/http"
 	"os"
+	"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"`
@@ -95,10 +100,12 @@ func handler(w http.ResponseWriter, req *http.Request) {
 }
 
 func ping(w http.ResponseWriter, req *http.Request) {
-	// get h, p, t parameters from query string
+	// 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 == "" {
@@ -114,12 +121,25 @@ func ping(w http.ResponseWriter, req *http.Request) {
 		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 = "tcp"
+		network = PING_DEFAULT_NETWORK
 	}
-	// ping the hostname and port by opening a socket
-	err := pingHost(hostname, port, 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")
@@ -132,9 +152,12 @@ func ping(w http.ResponseWriter, req *http.Request) {
 	json.NewEncoder(w).Encode(&successResponse{"ping succeeded"})
 }
 
-func pingHost(hostname, port, network string) error {
+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.Dial(network, hostname+":"+port)
+	conn, err := net.DialTimeout(network, hostname+":"+port, timeoutDuration)
 	if err != nil {
 		return err
 	}

server_test.go

@@ -235,3 +235,71 @@ func TestHandlerPreflight(t *testing.T) {
 	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)
+}