From 5defafe5f6bf2173db3368573c87d20fc2df32db Mon Sep 17 00:00:00 2001
From: Jay Zhang <wangyoucao577@gmail.com>
Date: Mon, 7 Oct 2019 15:13:00 +0800
Subject: [PATCH] feat: first implementation

---
 cmd/diagnosis/main.go  | 30 +++++++++++++++++
 diagnosis/diagnosis.go | 73 ++++++++++++++++++++++++++++++++++++++++++
 go.mod                 |  5 +++
 go.sum                 |  2 ++
 4 files changed, 110 insertions(+)
 create mode 100644 cmd/diagnosis/main.go
 create mode 100644 diagnosis/diagnosis.go
 create mode 100644 go.mod
 create mode 100644 go.sum

diff --git a/cmd/diagnosis/main.go b/cmd/diagnosis/main.go
new file mode 100644
index 0000000..72cb64b
--- /dev/null
+++ b/cmd/diagnosis/main.go
@@ -0,0 +1,30 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+
+	"github.com/wangyoucao577/go-project-layout/diagnosis"
+)
+
+func main() {
+
+	mux := http.NewServeMux()
+
+	//Sample Request: http://localhost:8000/diagnosis?diagnosis=ping
+	mux.HandleFunc("/diagnosis", func(w http.ResponseWriter, req *http.Request) {
+		item := req.URL.Query().Get("diagnosis")
+		if item == "ping" {
+			diagnosisInfo := diagnosis.New()
+			diagnosisInfo.RemoteAddr = req.RemoteAddr // dynamic update for each request
+			fmt.Fprintf(w, "%s", diagnosisInfo)
+			return
+		}
+
+		w.WriteHeader(http.StatusNotFound) //404
+		fmt.Fprintf(w, "no diagnosis command %s", req.URL)
+	})
+
+	log.Fatal(http.ListenAndServe(":8000", mux))
+}
diff --git a/diagnosis/diagnosis.go b/diagnosis/diagnosis.go
new file mode 100644
index 0000000..e155275
--- /dev/null
+++ b/diagnosis/diagnosis.go
@@ -0,0 +1,73 @@
+package diagnosis
+
+import (
+	"encoding/json"
+	"fmt"
+	"net"
+	"os"
+
+	"github.com/matishsiao/goInfo"
+)
+
+// Info includes information for diagnosis.
+type Info struct {
+	//static info
+	Hostname    string   `json:"Hostname"`
+	IPAddresses []string `json:"IP Addresses"` //readable format, like x.x.x.x or ::1
+	CPUs        int      `json:"CPUs"`
+
+	//dynamic info for per request
+	RemoteAddr string `json:"Remote Endpoint"`
+}
+
+// New fetchs information for diagnosis.
+func New() *Info {
+	var info Info
+
+	//hostname
+	hostname, err := os.Hostname()
+	if err != nil {
+		fmt.Printf("get hostname failed, err %v\n", err)
+	} else {
+		fmt.Printf("Hostname: %s\n", hostname)
+		info.Hostname = hostname
+	}
+
+	//ip addresses
+	addrs, err := net.InterfaceAddrs()
+	if err != nil {
+		fmt.Printf("lookup network interface addrs failed, err %v\n", err)
+	} else {
+		for _, addr := range addrs {
+			ip, _, err := net.ParseCIDR(addr.String())
+			if err != nil {
+				fmt.Printf("ParseCIDR addrs failed, err %v\n", err)
+				continue
+			}
+
+			if ip.IsLoopback() {
+				fmt.Printf("ignore Loopback ip address-->%s\n", addr.String())
+				continue
+			}
+
+			fmt.Printf("%s ip address-->%s\n", addr.Network(), addr.String())
+			info.IPAddresses = append(info.IPAddresses, addr.String())
+		}
+	}
+
+	//from goInfo
+	gi := goInfo.GetInfo()
+	gi.VarDump()
+	info.CPUs = gi.CPUs
+
+	return &info
+}
+
+func (info Info) String() string {
+	jsonstr, err := json.Marshal(info)
+	if err != nil {
+		fmt.Printf("to json failed, err %v\n", err)
+		return err.Error()
+	}
+	return string(jsonstr)
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..8328705
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,5 @@
+module github.com/wangyoucao577/go-project-layout
+
+go 1.13
+
+require github.com/matishsiao/goInfo v0.0.0-20170803142006-617e6440957e
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..01bfd9b
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,2 @@
+github.com/matishsiao/goInfo v0.0.0-20170803142006-617e6440957e h1:Y+GY+bv5vf1gssphFsGiq6R8qdHxnpDZvYljFnXfhD8=
+github.com/matishsiao/goInfo v0.0.0-20170803142006-617e6440957e/go.mod h1:yLZrFIhv+Z20hxHvcZpEyKVQp9HMsOJkXAxx7yDqtvg=