PLT-4357 adding performance monitoring (#4622)

* WIP

* WIP

* Adding metrics collection

* updating vendor packages

* Adding metrics to config

* Adding admin console page for perf monitoring

* Updating glide

* switching to tylerb/graceful

vendor/github.com/prometheus/common/route/route.go

@@ -0,0 +1,137 @@
+package route
+
+import (
+	"fmt"
+	"net/http"
+	"sync"
+
+	"github.com/julienschmidt/httprouter"
+	"golang.org/x/net/context"
+)
+
+var (
+	mtx   = sync.RWMutex{}
+	ctxts = map[*http.Request]context.Context{}
+)
+
+// Context returns the context for the request.
+func Context(r *http.Request) context.Context {
+	mtx.RLock()
+	defer mtx.RUnlock()
+	return ctxts[r]
+}
+
+type param string
+
+// Param returns param p for the context.
+func Param(ctx context.Context, p string) string {
+	return ctx.Value(param(p)).(string)
+}
+
+// WithParam returns a new context with param p set to v.
+func WithParam(ctx context.Context, p, v string) context.Context {
+	return context.WithValue(ctx, param(p), v)
+}
+
+type contextFn func(r *http.Request) (context.Context, error)
+
+// Router wraps httprouter.Router and adds support for prefixed sub-routers
+// and per-request context injections.
+type Router struct {
+	rtr    *httprouter.Router
+	prefix string
+	ctxFn  contextFn
+}
+
+// New returns a new Router.
+func New(ctxFn contextFn) *Router {
+	if ctxFn == nil {
+		ctxFn = func(r *http.Request) (context.Context, error) {
+			return context.Background(), nil
+		}
+	}
+	return &Router{
+		rtr:   httprouter.New(),
+		ctxFn: ctxFn,
+	}
+}
+
+// WithPrefix returns a router that prefixes all registered routes with prefix.
+func (r *Router) WithPrefix(prefix string) *Router {
+	return &Router{rtr: r.rtr, prefix: r.prefix + prefix, ctxFn: r.ctxFn}
+}
+
+// handle turns a HandlerFunc into an httprouter.Handle.
+func (r *Router) handle(h http.HandlerFunc) httprouter.Handle {
+	return func(w http.ResponseWriter, req *http.Request, params httprouter.Params) {
+		reqCtx, err := r.ctxFn(req)
+		if err != nil {
+			http.Error(w, fmt.Sprintf("Error creating request context: %v", err), http.StatusBadRequest)
+			return
+		}
+		ctx, cancel := context.WithCancel(reqCtx)
+		defer cancel()
+
+		for _, p := range params {
+			ctx = context.WithValue(ctx, param(p.Key), p.Value)
+		}
+
+		mtx.Lock()
+		ctxts[req] = ctx
+		mtx.Unlock()
+
+		h(w, req)
+
+		mtx.Lock()
+		delete(ctxts, req)
+		mtx.Unlock()
+	}
+}
+
+// Get registers a new GET route.
+func (r *Router) Get(path string, h http.HandlerFunc) {
+	r.rtr.GET(r.prefix+path, r.handle(h))
+}
+
+// Options registers a new OPTIONS route.
+func (r *Router) Options(path string, h http.HandlerFunc) {
+	r.rtr.OPTIONS(r.prefix+path, r.handle(h))
+}
+
+// Del registers a new DELETE route.
+func (r *Router) Del(path string, h http.HandlerFunc) {
+	r.rtr.DELETE(r.prefix+path, r.handle(h))
+}
+
+// Put registers a new PUT route.
+func (r *Router) Put(path string, h http.HandlerFunc) {
+	r.rtr.PUT(r.prefix+path, r.handle(h))
+}
+
+// Post registers a new POST route.
+func (r *Router) Post(path string, h http.HandlerFunc) {
+	r.rtr.POST(r.prefix+path, r.handle(h))
+}
+
+// Redirect takes an absolute path and sends an internal HTTP redirect for it,
+// prefixed by the router's path prefix. Note that this method does not include
+// functionality for handling relative paths or full URL redirects.
+func (r *Router) Redirect(w http.ResponseWriter, req *http.Request, path string, code int) {
+	http.Redirect(w, req, r.prefix+path, code)
+}
+
+// ServeHTTP implements http.Handler.
+func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	r.rtr.ServeHTTP(w, req)
+}
+
+// FileServe returns a new http.HandlerFunc that serves files from dir.
+// Using routes must provide the *filepath parameter.
+func FileServe(dir string) http.HandlerFunc {
+	fs := http.FileServer(http.Dir(dir))
+
+	return func(w http.ResponseWriter, r *http.Request) {
+		r.URL.Path = Param(Context(r), "filepath")
+		fs.ServeHTTP(w, r)
+	}
+}

vendor/github.com/prometheus/common/route/route_test.go

@@ -0,0 +1,75 @@
+package route
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"golang.org/x/net/context"
+)
+
+func TestRedirect(t *testing.T) {
+	router := New(nil).WithPrefix("/test/prefix")
+	w := httptest.NewRecorder()
+	r, err := http.NewRequest("GET", "http://localhost:9090/foo", nil)
+	if err != nil {
+		t.Fatalf("Error building test request: %s", err)
+	}
+
+	router.Redirect(w, r, "/some/endpoint", http.StatusFound)
+	if w.Code != http.StatusFound {
+		t.Fatalf("Unexpected redirect status code: got %d, want %d", w.Code, http.StatusFound)
+	}
+
+	want := "/test/prefix/some/endpoint"
+	got := w.Header()["Location"][0]
+	if want != got {
+		t.Fatalf("Unexpected redirect location: got %s, want %s", got, want)
+	}
+}
+
+func TestContextFn(t *testing.T) {
+	router := New(func(r *http.Request) (context.Context, error) {
+		return context.WithValue(context.Background(), "testkey", "testvalue"), nil
+	})
+
+	router.Get("/test", func(w http.ResponseWriter, r *http.Request) {
+		want := "testvalue"
+		got := Context(r).Value("testkey")
+		if want != got {
+			t.Fatalf("Unexpected context value: want %q, got %q", want, got)
+		}
+	})
+
+	r, err := http.NewRequest("GET", "http://localhost:9090/test", nil)
+	if err != nil {
+		t.Fatalf("Error building test request: %s", err)
+	}
+	router.ServeHTTP(nil, r)
+}
+
+func TestContextFnError(t *testing.T) {
+	router := New(func(r *http.Request) (context.Context, error) {
+		return context.Background(), fmt.Errorf("test error")
+	})
+
+	router.Get("/test", func(w http.ResponseWriter, r *http.Request) {})
+
+	r, err := http.NewRequest("GET", "http://localhost:9090/test", nil)
+	if err != nil {
+		t.Fatalf("Error building test request: %s", err)
+	}
+	w := httptest.NewRecorder()
+	router.ServeHTTP(w, r)
+
+	if w.Code != http.StatusBadRequest {
+		t.Fatalf("Unexpected response status: got %q, want %q", w.Code, http.StatusBadRequest)
+	}
+
+	want := "Error creating request context: test error\n"
+	got := w.Body.String()
+	if want != got {
+		t.Fatalf("Unexpected response body: got %q, want %q", got, want)
+	}
+}