From 94adb97ac1660a9e680be216c2c1f7e8e42587f1 Mon Sep 17 00:00:00 2001
From: "A.Unger" <zyxancf@gmail.com>
Date: Thu, 9 Jul 2020 14:15:20 +0200
Subject: [PATCH] create root span on ocis-proxy

---
 go.sum                 |  1 +
 pkg/command/server.go  |  3 +++
 pkg/flagset/flagset.go |  2 +-
 pkg/proxy/proxy.go     | 21 +++++++++++++++++++--
 4 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/go.sum b/go.sum
index 75aeda852a..1abba4df56 100644
--- a/go.sum
+++ b/go.sum
@@ -175,6 +175,7 @@ github.com/cespare/xxhash v1.1.0 h1:a6HrQnmkObjyL+Gs60czilIUGqrzKutQD6XZog3p+ko=
 github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
 github.com/cespare/xxhash/v2 v2.1.0 h1:yTUvW7Vhb89inJ+8irsUqiWjh8iT6sQPZiQzI6ReGkA=
 github.com/cespare/xxhash/v2 v2.1.0/go.mod h1:dgIUBU3pDso/gPgZ1osOZ0iQf77oPR28Tjxl5dIMyVM=
+github.com/cespare/xxhash/v2 v2.1.1 h1:6MnRN8NT7+YBpUIWxHtefFZOKTAPgGjpQSxqLNn0+qY=
 github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/cheekybits/genny v1.0.0/go.mod h1:+tQajlRqAUrPI7DOSpB0XAqZYtQakVtB7wXkRAgjxjQ=
 github.com/cheggaaa/pb v1.0.28/go.mod h1:pQciLPpbU0oxA0h+VJYYLxO+XeDQb5pZijXscXHm81s=
diff --git a/pkg/command/server.go b/pkg/command/server.go
index 916efc7875..59f3424e19 100644
--- a/pkg/command/server.go
+++ b/pkg/command/server.go
@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
+	"strconv"
 	"strings"
 	"time"
 
@@ -42,6 +43,8 @@ func Server(cfg *config.Config) *cli.Command {
 		Usage: "Start integrated server",
 		Flags: flagset.ServerWithConfig(cfg),
 		Before: func(ctx *cli.Context) error {
+			l := NewLogger(cfg)
+			l.Debug().Str("tracing", strconv.FormatBool(cfg.Tracing.Enabled)).Msg("init: before")
 			if cfg.HTTP.Root != "/" {
 				cfg.HTTP.Root = strings.TrimSuffix(cfg.HTTP.Root, "/")
 			}
diff --git a/pkg/flagset/flagset.go b/pkg/flagset/flagset.go
index bb72c29a3e..ad9b714293 100644
--- a/pkg/flagset/flagset.go
+++ b/pkg/flagset/flagset.go
@@ -77,7 +77,7 @@ func ServerWithConfig(cfg *config.Config) []cli.Flag {
 		},
 		&cli.StringFlag{
 			Name:        "tracing-collector",
-			Value:       "",
+			Value:       "http://localhost:14268/api/traces",
 			Usage:       "Endpoint for the collector",
 			EnvVars:     []string{"PROXY_TRACING_COLLECTOR"},
 			Destination: &cfg.Tracing.Collector,
diff --git a/pkg/proxy/proxy.go b/pkg/proxy/proxy.go
index 5d1340bdf6..9b1fc83bd3 100644
--- a/pkg/proxy/proxy.go
+++ b/pkg/proxy/proxy.go
@@ -1,13 +1,17 @@
 package proxy
 
 import (
-	"github.com/owncloud/ocis-proxy/pkg/proxy/policy"
+	"context"
 	"net/http"
 	"net/http/httputil"
 	"net/url"
 	"regexp"
 	"strings"
 
+	"github.com/owncloud/ocis-proxy/pkg/proxy/policy"
+	"go.opencensus.io/plugin/ochttp/propagation/tracecontext"
+	"go.opencensus.io/trace"
+
 	"github.com/owncloud/ocis-pkg/v2/log"
 	"github.com/owncloud/ocis-proxy/pkg/config"
 )
@@ -18,6 +22,8 @@ type MultiHostReverseProxy struct {
 	Directors      map[string]map[config.RouteType]map[string]func(req *http.Request)
 	PolicySelector policy.Selector
 	logger         log.Logger
+	propagator     tracecontext.HTTPFormat
+	config         *config.Config
 }
 
 // NewMultiHostReverseProxy undocummented
@@ -27,6 +33,7 @@ func NewMultiHostReverseProxy(opts ...Option) *MultiHostReverseProxy {
 	rp := &MultiHostReverseProxy{
 		Directors: make(map[string]map[config.RouteType]map[string]func(req *http.Request)),
 		logger:    options.Logger,
+		config:    options.Config,
 	}
 
 	if options.Config.Policies == nil {
@@ -140,6 +147,16 @@ func (p *MultiHostReverseProxy) ServeHTTP(w http.ResponseWriter, r *http.Request
 			Msgf("policy %v is not configured", pol)
 	}
 
+	var ctx context.Context
+	var span *trace.Span
+
+	// Start root span.
+	if p.config.Tracing.Enabled {
+		ctx, span = trace.StartSpan(context.Background(), r.URL.String())
+		defer span.End()
+		p.propagator.SpanContextToRequest(span.SpanContext(), r)
+	}
+
 Loop:
 	for _, rt := range config.RouteTypes {
 		var handler func(string, url.URL) bool
@@ -175,7 +192,7 @@ Loop:
 	}
 
 	// Call upstream ServeHTTP
-	p.ReverseProxy.ServeHTTP(w, r)
+	p.ReverseProxy.ServeHTTP(w, r.WithContext(ctx))
 }
 
 func (p MultiHostReverseProxy) queryRouteMatcher(endpoint string, target url.URL) bool {