README: add screenshots of traces + metrics

Author: odeke-em

README.md

@@ -1,2 +1,93 @@
 # gomongowrapper
 MongoDB Go wrapper source code
+
+## Table of contents
+- [End to end example](#end-to-end-example)
+- [Traces](#traces)y
+- [Metrics](#metrics)
+
+## End to end example
+With a MongoDB server running at "localhost:27017" and running this example with Go
+
+```go
+package main
+
+import (
+	"context"
+	"log"
+	"time"
+
+	"github.com/mongodb/mongo-go-driver/bson"
+
+	"github.com/opencensus-integrations/gomongowrapper"
+
+	"contrib.go.opencensus.io/exporter/stackdriver"
+	"go.opencensus.io/stats/view"
+	"go.opencensus.io/trace"
+)
+
+func main() {
+	// Enabling the OpenCensus exporter.
+	// Just using Stackdriver since it has both Tracing and Metrics
+	// and is easy to whip up. Add your desired one here.
+	sde, err := stackdriver.NewExporter(stackdriver.Options{
+		ProjectID:    "census-demos",
+		MetricPrefix: "mongosample",
+	})
+	if err != nil {
+		log.Fatalf("Failed to create Stackdriver exporter: %v", err)
+	}
+	view.RegisterExporter(sde)
+	trace.RegisterExporter(sde)
+	if err := mongowrapper.RegisterAllViews(); err != nil {
+		log.Fatalf("Failed to register all views: %v\n", err)
+	}
+
+	defer func() {
+		<-time.After(2 * time.Minute)
+	}()
+
+	// Start a span like your application would start one.
+	ctx, span := trace.StartSpan(context.Background(), "Fetch", trace.WithSampler(trace.AlwaysSample()))
+	defer span.End()
+
+        // Now for the mongo connections, using the context
+        // with the span in it for continuity.
+	client, err := mongowrapper.NewClient("mongodb://localhost:27017")
+	if err != nil {
+		log.Fatalf("Failed to create the new client: %v", err)
+	}
+	if err := client.Connect(ctx); err != nil {
+		log.Fatalf("Failed to open client connection: %v", err)
+	}
+	defer client.Disconnect(ctx)
+	coll := client.Database("the_db").Collection("music")
+
+	q := bson.M{"name": "Examples"}
+	cur, err := coll.Find(ctx, q)
+	if err != nil {
+		log.Fatalf("Find error: %v", err)
+	}
+
+	for cur.Next(ctx) {
+		elem := make(map[string]int)
+		if err := cur.Decode(elem); err != nil {
+			log.Printf("Decode error: %v", err)
+			continue
+		}
+		log.Printf("Got result: %v\n", elem)
+	}
+	log.Print("Done iterating")
+
+	_, err = coll.DeleteMany(ctx, q)
+	if err != nil {
+		log.Fatalf("Failed to delete: %v", err)
+	}
+}
+```
+
+## Traces
+![](/images/gomongowrapper-traces.png)
+
+## Metrics
+![](/images/gomongowrapper-metrics.png)

example_test.go

@@ -17,24 +17,54 @@ package mongowrapper_test
 import (
 	"context"
 	"log"
+	"time"
 
 	"github.com/mongodb/mongo-go-driver/bson"
 
 	"github.com/opencensus-integrations/gomongowrapper"
 
+	"contrib.go.opencensus.io/exporter/stackdriver"
+	"go.opencensus.io/stats/view"
 	"go.opencensus.io/trace"
 )
 
 func Example() {
-	client, err := mongowrapper.NewClient("mongodb://foo:bar@localhost:27017")
+	// Enabling the OpenCensus exporter.
+	// Just using Stackdriver since it has both Tracing and Metrics
+	// and is easy to whip up. Add your desired one here.
+	sde, err := stackdriver.NewExporter(stackdriver.Options{
+		ProjectID:    "census-demos",
+		MetricPrefix: "mongosample",
+	})
 	if err != nil {
-		log.Fatalf("Failed to create the new client: %v", err)
+		log.Fatalf("Failed to create Stackdriver exporter: %v", err)
 	}
-	coll := client.Database("the_db").Collection("music")
+	view.RegisterExporter(sde)
+	trace.RegisterExporter(sde)
+	if err := mongowrapper.RegisterAllViews(); err != nil {
+		log.Fatalf("Failed to register all views: %v\n", err)
+	}
+
+	defer func() {
+		<-time.After(2 * time.Minute)
+	}()
 
-	ctx, span := trace.StartSpan(context.Background(), "Fetch")
+	// Start a span like your application would start one.
+	ctx, span := trace.StartSpan(context.Background(), "Fetch", trace.WithSampler(trace.AlwaysSample()))
 	defer span.End()
 
+        // Now for the mongo connections, using the context
+        // with the span in it for continuity.
+	client, err := mongowrapper.NewClient("mongodb://localhost:27017")
+	if err != nil {
+		log.Fatalf("Failed to create the new client: %v", err)
+	}
+	if err := client.Connect(ctx); err != nil {
+		log.Fatalf("Failed to open client connection: %v", err)
+	}
+	defer client.Disconnect(ctx)
+	coll := client.Database("the_db").Collection("music")
+
 	q := bson.M{"name": "Examples"}
 	cur, err := coll.Find(ctx, q)
 	if err != nil {
@@ -49,4 +79,10 @@ func Example() {
 		}
 		log.Printf("Got result: %v\n", elem)
 	}
+	log.Print("Done iterating")
+
+	_, err = coll.DeleteMany(ctx, q)
+	if err != nil {
+		log.Fatalf("Failed to delete: %v", err)
+	}
 }