opentracing -> opencensus (#802)

* update vendor directory, add go.opencensus.io

* update imports

* oops

* s/opentracing/opencensus/ & remove prometheus / zipkin stuff & remove old stats

* the dep train rides again

* fix gin build

* deps from last guy

* start in on the agent metrics

* she builds

* remove tags for now, cardinality error is fussing. subscribe instead of register

* update to patched version of opencensus to proceed for now TODO switch to a release

* meh

fix imports

* println debug the bad boys

* lace it with the tags

* update deps again

* fix all inconsistent cardinality errors

* add our own logger

* fix init

* fix oom measure

* remove bugged removal code

* fix s3 measures

* fix prom handler nil

api/agent/resource.go

@@ -13,7 +13,8 @@ import (
 	"strings"
 	"sync"
 
-	opentracing "github.com/opentracing/opentracing-go"
+	"go.opencensus.io/trace"
+
 	"github.com/sirupsen/logrus"
 )
 
@@ -166,9 +167,9 @@ func (a *resourceTracker) GetResourceToken(ctx context.Context, memory uint64, c
 		c.L.Unlock()
 	}()
 
-	span, ctx := opentracing.StartSpanFromContext(ctx, "agent_get_resource_token")
+	ctx, span := trace.StartSpan(ctx, "agent_get_resource_token")
 	go func() {
-		defer span.Finish()
+		defer span.End()
 		defer cancel()
 		c.L.Lock()
 
@@ -254,9 +255,9 @@ func (a *resourceTracker) WaitAsyncResource(ctx context.Context) chan struct{} {
 		c.L.Unlock()
 	}()
 
-	span, ctx := opentracing.StartSpanFromContext(ctx, "agent_wait_async_resource")
+	ctx, span := trace.StartSpan(ctx, "agent_wait_async_resource")
 	go func() {
-		defer span.Finish()
+		defer span.End()
 		defer cancel()
 		c.L.Lock()
 		isWaiting = true