Introspection 7/7, /debug/yarpc debug page (#643)

Finally, the suspens killing part of this serie of PRs, the yarpc debug page, pretty printing the introspection data into HTML.
yarpc · Dec 28, 2016 · 15bf66e · 15bf66e
1 parent 164a6e1
commit 15bf66e
Show file tree

Hide file tree

Showing 3 changed files with 210 additions and 2 deletions.
diff --git a/debug.go b/debug.go
@@ -0,0 +1,197 @@
+// Copyright (c) 2016 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package yarpc
+
+import (
+	"html/template"
+	"io"
+	"log"
+	"net/http"
+	"sync"
+)
+
+var (
+	dispatchersLock sync.RWMutex
+	dispatchers     []*Dispatcher
+)
+
+func addDispatcherToDebugPages(disp *Dispatcher) {
+	dispatchersLock.Lock()
+	defer dispatchersLock.Unlock()
+
+	dispatchers = append(dispatchers, disp)
+}
+
+func removeDispatcherFromDebugPages(disp *Dispatcher) {
+	dispatchersLock.Lock()
+	defer dispatchersLock.Unlock()
+
+	for i, x := range dispatchers {
+		if x == disp {
+			copy(dispatchers[i:], dispatchers[i+1:])
+			dispatchers[len(dispatchers)-1] = nil
+			dispatchers = dispatchers[:len(dispatchers)-1]
+			break
+		}
+	}
+}
+
+func init() {
+	http.HandleFunc("/debug/yarpc", func(w http.ResponseWriter, req *http.Request) {
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		render(w, req)
+	})
+}
+
+func render(w io.Writer, req *http.Request) {
+	var data struct {
+		Dispatchers []dispatcherStatus
+	}
+
+	for _, disp := range dispatchers {
+		data.Dispatchers = append(data.Dispatchers, disp.introspect())
+	}
+
+	if err := pageTmpl.ExecuteTemplate(w, "Page", data); err != nil {
+		log.Printf("yarpc/debug: Failed executing template: %v", err)
+	}
+}
+
+var pageTmpl = template.Must(template.New("Page").Funcs(template.FuncMap{}).Parse(pageHTML))
+
+const pageHTML = `
+<html>
+	<head>
+	<title>/debug/yarpc</title>
+	<style type="text/css">
+		body {
+			font-family: "Courier New", Courier, monospace;
+		}
+		table {
+			color:#333333;
+			border-width: 1px;
+			border-color: #3A3A3A;
+			border-collapse: collapse;
+		}
+		table th {
+			border-width: 1px;
+			padding: 8px;
+			border-style: solid;
+			border-color: #3A3A3A;
+			background-color: #B3B3B3;
+		}
+		table td {
+			border-width: 1px;
+			padding: 8px;
+			border-style: solid;
+			border-color: #3A3A3A;
+			background-color: #ffffff;
+		}
+	</style>
+	</head>
+	<body>
+
+<h1>/debug/yarpc</h1>
+
+{{range .Dispatchers}}
+	<hr />
+	<h2>Dispatcher "{{.Name}}" <small>({{.ID}})</small></h2>
+	<table>
+		<tr>
+			<th>Service</th>
+			<th>Procedure</th>
+			<th>Encoding</th>
+			<th>Signature</th>
+			<th>Flavor</th>
+		</tr>
+		{{range .Procedures}}
+		<tr>
+			<td>{{.Service}}</td>
+			<td>{{.Name}}</td>
+			<td>{{.Encoding}}</td>
+			<td>{{.Signature}}</td>
+			<td>{{.HandlerSpec.Type}}</td>
+		</tr>
+		{{end}}
+	</table>
+	<h3>Inbounds</h3>
+	<table>
+		<tr>
+			<th>Transport</th>
+			<th>Endpoint</th>
+			<th>State</th>
+		</tr>
+		{{range .Inbounds}}
+		<tr>
+			<td>{{.Transport}}</td>
+			<td>{{.Endpoint}}</td>
+			<td>{{.State}}</td>
+		</tr>
+		{{end}}
+	</table>
+	<h3>Outbounds</h3>
+	<table>
+		<thead>
+		<tr>
+			<th>Service</th>
+			<th>Transport</th>
+			<th>Flavor</th>
+			<th>Endpoint</th>
+			<th>State</th>
+			<th colspan="3">Chooser</th>
+		</tr>
+		<tr>
+			<th></th>
+			<th></th>
+			<th></th>
+			<th></th>
+			<th></th>
+			<th>Name</th>
+			<th>State</th>
+			<th>Peers</th>
+		</tr>
+		</thead>
+		<tbody>
+		{{range .Outbounds}}
+		<tr>
+			<td>{{.Service}}</td>
+			<td>{{.Transport}}</td>
+			<td>{{.Flavor}}</td>
+			<td>{{.Endpoint}}</td>
+			<td>{{.State}}</td>
+			<td>{{.Chooser.Name}}</td>
+			<td>{{.Chooser.State}}</td>
+			<td>
+				<ul>
+				{{range .Chooser.Peers}}
+					<li>{{.Identifier}} ({{.State}})</li>
+				{{end}}
+				</ul>
+			</td>
+		</tr>
+		</tbody>
+		{{end}}
+	</table>
+{{end}}
+
+	</body>
+</html>
+`
diff --git a/dispatcher.go b/dispatcher.go
@@ -324,6 +324,7 @@ func (d *Dispatcher) Start() error {
 		return abort(errs)
 	}
 
+	addDispatcherToDebugPages(d)
 	return nil
 }
 
@@ -380,6 +381,8 @@ func (d *Dispatcher) Stop() error {
 	if len(allErrs) > 0 {
 		return errors.ErrorGroup(allErrs)
 	}
+
+	removeDispatcherFromDebugPages(d)
 	return nil
 }
 

diff --git a/internal/examples/thrift-keyvalue/Makefile b/internal/examples/thrift-keyvalue/Makefile
@@ -1,4 +1,12 @@
-.PHONY: all
-all:
+.PHONY: all hello kvserver kvclient
+
+all: hello kvserver kvclient
+
+hello:
+	cd hello; go build -i
+
+kvclient:
 	cd keyvalue/client; go build -i
+
+kvserver:
 	cd keyvalue/server; go build -i