Add Example App (close #75)

* Add example app (#76)

examples/README.md

@@ -0,0 +1,16 @@
+# Example App
+
+This example shows how to set up the golang tracker to send events to a Snowplow pipeline.
+
+#### Installation
+- Install the golang tracker.
+
+`$host go get "github.com/snowplow/snowplow-golang-tracker/v3/tracker"` 
+
+#### Usage
+Navigate to the example folder.
+
+`cd examples`
+
+To send events to your pipeline, run `go run main.go {{your_collector_endpoint}}`. You should see 4 events in your pipleine.
+

examples/main.go

@@ -0,0 +1,80 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"os"
+
+	sphelp "github.com/snowplow/snowplow-golang-tracker/v3/pkg/common"
+	storagememory "github.com/snowplow/snowplow-golang-tracker/v3/pkg/storage/memory"
+	sp "github.com/snowplow/snowplow-golang-tracker/v3/tracker"
+)
+
+func getUrlFromArgs() (string, error) {
+	if len(os.Args) != 2 {
+		return "", errors.New("collector endpoint is required")
+	}
+	return os.Args[1], nil
+}
+
+func main() {
+	collectorUri, err := getUrlFromArgs()
+
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	emitter := sp.InitEmitter(
+		sp.RequireCollectorUri(collectorUri),
+		sp.RequireStorage(*storagememory.Init()),
+		sp.OptionRequestType("POST"),
+		sp.OptionProtocol("http"),
+		sp.OptionSendLimit(4),
+	)
+
+	subject := sp.InitSubject()
+	subject.SetLanguage("en")
+	subject.SetScreenResolution(1280, 720)
+
+	tracker := sp.InitTracker(
+		sp.RequireEmitter(emitter),
+		sp.OptionSubject(subject),
+	)
+
+	fmt.Println("Sending events to " + emitter.GetCollectorUrl())
+
+	pageView := sp.PageViewEvent{
+		PageUrl: sphelp.NewString("acme.com"),
+	}
+	tracker.TrackPageView(pageView)
+
+	screenView := sp.ScreenViewEvent{
+		Name: sphelp.NewString("name"),
+		Id:   sphelp.NewString("Screen ID"),
+	}
+	tracker.TrackScreenView(screenView)
+
+	structEvent := sp.StructuredEvent{
+		Category: sphelp.NewString("shop"),
+		Action:   sphelp.NewString("add-to-basket"),
+		Property: sphelp.NewString("pcs"),
+		Value:    sphelp.NewFloat64(2),
+	}
+
+	tracker.TrackStructEvent(structEvent)
+
+	data := map[string]interface{}{
+		"targetUrl": "https://www.snowplow.io",
+	}
+
+	sdj := sp.InitSelfDescribingJson("iglu:com.snowplowanalytics.snowplow/link_click/jsonschema/1-0-1", data)
+
+	sde := sp.SelfDescribingEvent{Event: sdj}
+
+	tracker.TrackSelfDescribingEvent(sde)
+
+	tracker.Emitter.Stop()
+	tracker.BlockingFlush(5, 10)
+
+}