Add debug API. This can be used for profiling.

API.go

@@ -44,6 +44,10 @@ func startAPI(backend *core.Backend, apiListen []string, apiKey uuid.UUID) {
 	api.AllowKeyInParam = append(api.AllowKeyInParam, "/console")
 	api.Router.HandleFunc("/console", apiConsole(backend)).Methods("GET")
 	api.Router.HandleFunc("/shutdown", apiShutdown(backend)).Methods("GET")
+
+	if config.DebugAPI {
+		attachDebugAPI(api)
+	}
 }
 
 // parseCmdParams parses the "-webapi", "-apikey", and "-watchpid" command line parameters.

Debug empty.go

@@ -0,0 +1,11 @@
+//go:build !debug
+// +build !debug
+
+package main
+
+import (
+	"github.com/PeernetOfficial/core/webapi"
+)
+
+func attachDebugAPI(api *webapi.WebapiInstance) {
+}

Debug.go

@@ -0,0 +1,98 @@
+//go:build debug
+// +build debug
+
+/*
+File Name:  Debug.go
+Copyright:  2017 Kleissner Investments s.r.o.
+Author:     Peter Kleissner
+
+Debug runtime functionality. The functions only work if the config setting DebugAPI is enabled.
+*/
+
+package main
+
+import (
+	"net/http"
+	"net/http/pprof" // Warning: If the default HTTP handler is used, this installs handlers!
+	"runtime"
+
+	"github.com/PeernetOfficial/core/webapi"
+)
+
+// apiDebugBugcheck handles /debug/bugcheck
+func apiDebugBugcheck(w http.ResponseWriter, r *http.Request) {
+
+	if !config.DebugAPI {
+		http.Error(w, "", http.StatusOK)
+		return
+	}
+
+	http.Error(w, "Executing immediate bugcheck", http.StatusOK)
+
+	panic("via /debug/bugcheck")
+}
+
+// apiDebugStack handles /debug/stack
+func apiDebugStack(w http.ResponseWriter, r *http.Request) {
+
+	if !config.DebugAPI {
+		http.Error(w, "", http.StatusOK)
+		return
+	}
+
+	buffer := make([]byte, 1*1024*1024)
+	size := runtime.Stack(buffer, true)
+
+	http.Error(w, string(buffer[:size]), http.StatusOK)
+}
+
+func attachDebugAPI(api *webapi.WebapiInstance) {
+	api.AllowKeyInParam = append(api.AllowKeyInParam, []string{
+		"/debug/bugcheck",
+		"/debug/stack",
+		"/debug/pprof",
+		"/debug/pprof/cmdline",
+		"/debug/pprof/profile",
+		"/debug/pprof/symbol",
+		"/debug/pprof/trace",
+		"/debug/pprof/goroutine",
+		"/debug/pprof/heap",
+		"/debug/pprof/threadcreate",
+		"/debug/pprof/block",
+		"/debug/pprof/allocs",
+		"/debug/pprof/mutex",
+	}...)
+
+	api.Router.HandleFunc("/debug/bugcheck", apiDebugBugcheck)
+	api.Router.HandleFunc("/debug/stack", apiDebugStack)
+
+	api.Router.HandleFunc("/debug/pprof", pprof.Index)
+	api.Router.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
+	api.Router.HandleFunc("/debug/pprof/profile", pprof.Profile)
+	api.Router.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
+	api.Router.HandleFunc("/debug/pprof/trace", pprof.Trace)
+
+	// Manually add support for paths linked to by index page at /debug/pprof/
+	api.Router.Handle("/debug/pprof/goroutine", pprof.Handler("goroutine"))
+	api.Router.Handle("/debug/pprof/heap", pprof.Handler("heap"))
+	api.Router.Handle("/debug/pprof/threadcreate", pprof.Handler("threadcreate"))
+	api.Router.Handle("/debug/pprof/block", pprof.Handler("block"))
+	api.Router.Handle("/debug/pprof/allocs", pprof.Handler("allocs"))
+	api.Router.Handle("/debug/pprof/mutex", pprof.Handler("mutex"))
+}
+
+/*
+To use the pprof functionality set DebugAPI in the config to true and then use the right endpoints.
+
+For heap profiling:
+* While running, download the file http://[IP:Port]/debug/pprof/heap
+* Run "go tool pprof -http=127.0.0.1:80 [service].exe heap". The http parameter will open an interactive web-server.
+* pprof supports the following options. Default is inuse_space.
+  -inuse_space      Display in-use memory size
+  -inuse_objects    Display in-use object counts
+  -alloc_space      Display allocated memory size
+  -alloc_objects    Display allocated object counts
+* Instead of download the file in step 2, you can directly provide the full URL in step 3!
+
+Enabling DebugAPI shall not have any performance impact; it just installs the handlers. Only once a profiler is actually used, it may impact the performance.
+*/

Main.go

@@ -19,7 +19,8 @@ const appName = "Peernet Cmd"
 
 var config struct {
 	// Log settings
-	ErrorOutput int `yaml:"ErrorOutput"` // 0 = Log file (default),  1 = Command line, 2 = Log file + command line, 3 = None
+	ErrorOutput int  `yaml:"ErrorOutput"` // 0 = Log file (default),  1 = Command line, 2 = Log file + command line, 3 = None
+	DebugAPI    bool `yaml:"DebugAPI"`    // Enables the debug API which allows profiling. Do not enable in production. Only available if compiled with debug tag.
 
 	// API settings
 	APIListen          []string  `yaml:"APIListen"`          // WebListen is in format IP:Port and declares where the web-interface should listen on. IP can also be ommitted to listen on any.

README.md

@@ -231,3 +231,21 @@ Use the parameter `-watchpid=[PID]` to specify a process ID to monitor for exit
 ```
 Cmd -watchpid=1234
 ```
+
+## Debug
+
+### Compile Debug Version
+
+A debug version that exposes multiple endpoints via `/debug` for profiling can be compiled by using the debug tag:
+
+```
+go build -tags debug
+```
+
+### Use the Profiler
+
+Once started attach the profiler `go tool pprof`. Note that `/debug` endpoints are not excluded from API authentication. If an API key is used, it can be provided via the `&k=` parameter.
+
+```
+go tool pprof -http=127.0.0.1:80 Cmd.exe http://127.0.0.1:1337/debug/pprof/heap?k=a30c01eb-856c-4b79-bdde-3c56a248f71b
+```

go.mod

@@ -3,7 +3,7 @@ module github.com/PeernetOfficial/Cmd
 go 1.16
 
 require (
-	github.com/PeernetOfficial/core v0.0.0-20211231003743-0689543d432f
+	github.com/PeernetOfficial/core v0.0.0-20220103002105-a19bac19163f
 	github.com/google/uuid v1.3.0
 	github.com/gorilla/websocket v1.4.3-0.20210424162022-e8629af678b7
 )

go.sum

@@ -1,7 +1,7 @@
 github.com/IncSW/geoip2 v0.1.1 h1:afzzYF7n9JbdcPy8aiBSgBJuXi4mTWXZ3z6V3o6Vg34=
 github.com/IncSW/geoip2 v0.1.1/go.mod h1:adcasR40vXiUBjtzdaTTKL/6wSf+fgO4M8Gve/XzPUk=
-github.com/PeernetOfficial/core v0.0.0-20211231003743-0689543d432f h1:jlHQnoboaX8vEX6PQdt86SUeLM77qR8WN0EyeH8dv5Q=
+github.com/PeernetOfficial/core v0.0.0-20220103002105-a19bac19163f h1:nkMU/dzSA61anIeBJGfCsq1+Ek6VR+BNXi4FnFkVu8k=
-github.com/PeernetOfficial/core v0.0.0-20211231003743-0689543d432f/go.mod h1:VNhfwAZqya5JDZTS/ffa8Shof0OmQCx025CQMieGB7o=
+github.com/PeernetOfficial/core v0.0.0-20220103002105-a19bac19163f/go.mod h1:VNhfwAZqya5JDZTS/ffa8Shof0OmQCx025CQMieGB7o=
 github.com/akrylysov/pogreb v0.10.1 h1:FqlR8VR7uCbJdfUob916tPM+idpKgeESDXOA1K0DK4w=
 github.com/akrylysov/pogreb v0.10.1/go.mod h1:pNs6QmpQ1UlTJKDezuRWmaqkgUE2TuU0YTWyqJZ7+lI=
 github.com/enfipy/locker v1.1.0 h1:2zVJ0ky7cS1Vjs0x6OQWFiT2dSEiHrI5/O2KCz1fgGc=