docs: update minio example (#244)

examples/Minio.md

@@ -12,7 +12,7 @@ options := &dockertest.RunOptions{
     Tag:        "latest",
     Cmd:        []string{"server", "/data"},
     PortBindings: map[dc.Port][]dc.PortBinding{
-        "9000": []dc.PortBinding{{HostPort: "9000"}},
+        "9000/tcp": []dc.PortBinding{{HostPort: "9000"}},
     },
     Env: []string{"MINIO_ACCESS_KEY=MYACCESSKEY", "MINIO_SECRET_KEY=MYSECRETKEY"},
 }
@@ -23,20 +23,43 @@ if err != nil {
 }
 
 endpoint := fmt.Sprintf("localhost:%s", resource.GetPort("9000/tcp"))
+// or you could use the following, because we mapped the port 9000 to the port 9000 on the host
+// endpoint := "localhost:9000"
 
 // exponential backoff-retry, because the application in the container might not be ready to accept connections yet
+// the minio client does not do service discovery for you (i.e. it does not check if connection can be established), so we have to use the health check
 if err := pool.Retry(func() error {
-    minioClient, err := minio.New(endpoint, "MYACCESSKEY", "MYSECRETKEY", true)
+    url := fmt.Sprintf("http://%s/minio/health/live", endpoint)
+    resp, err := http.Get(url)
     if err != nil {
-        log.Println("Failed to create minio client:", err)
         return err
     }
-    log.Printf("%#v\n", minioClient) // minioClient is now set up
+    if resp.StatusCode != http.StatusOK {
+        return fmt.Errorf("status code not OK")
+    }
     return nil
 }); err != nil {
     log.Fatalf("Could not connect to docker: %s", err)
 }
 
+// now we can instantiate minio client
+minioClient, err := minio.New(endpoint, &minio.Options{
+    Creds:  credentials.NewStaticV4("MYACCESSKEY", "MYSECRETKEY", ""),
+    Secure: false,
+})
+if err != nil {
+    log.Println("Failed to create minio client:", err)
+    return err
+}
+log.Printf("%#v\n", minioClient) // minioClient is now set up
+
+// now we can use the client, for example, to list the buckets
+buckets, err := minioClient.ListBuckets(context.Background())
+if err != nil {
+    log.Fatalf("error while listing buckets: %v", err)
+}
+fmt.Printf("buckets: %+v", buckets)
+
 // When you're done, kill and remove the container
 if err = pool.Purge(resource); err != nil {
     log.Fatalf("Could not purge resource: %s", err)