Merge pull request #267 from willhite/picasa-help

Add steps for getting Google oauth credentials to usage message.

clients/picasa/picasa.go

@@ -10,6 +10,7 @@ import (
 	"math/rand"
 	"net"
 	"net/http"
+	"os"
 	"strings"
 	"time"
 
@@ -23,8 +24,8 @@ import (
 )
 
 var (
-	apiKeyFlag       = flag.String("api-key", "", "API keys for Google can be created at https://console.developers.google.com")
-	apiKeySecretFlag = flag.String("api-key-secret", "", "API keys for Google can be created at https://console.developers.google.com")
+	apiKeyFlag       = flag.String("api-key", "", "API key from Google credentials. See below for help creating credentials:")
+	apiKeySecretFlag = flag.String("api-key-secret", "", "API secret from Google credentials. See below for help creating credentials")
 	albumIdFlag      = flag.String("album-id", "", "Import a specific album, identified by id")
 	ds               *dataset.Dataset
 	httpClient       *http.Client
@@ -58,7 +59,29 @@ type OauthToken struct {
 	RefreshToken string
 }
 
+func picasaUsage() {
+	credentialSteps := `How to create Google API credentials:
+  1) Go to http://console.developers.google.com/start
+  2) From the "Select a project" pull down menu, choose "Create a project..."
+  3) Fill in the "Project name" field (e.g. Picasa Importer)
+  4) Agree to the terms and conditions and hit continue.
+  5) Click on the "Select a project" pull down menu and choose "Manage all projects..."
+  6) Click on the project you just created. On the new page, in the sidebar menu,
+     click “APIs and auth”. In the submenu that opens up, click "Credentials".
+  7) In the popup, click on the "Add credentials" pulldown and select "OAuth 2.0 client ID".
+  8) Click the "Configure consent screen" button and fill in the "Product name" field.
+     All other fields on this page are optional. Now click the save button.
+  9) Select "Other" from the list of “Application Type” and fill in the “Name” field
+     (e.g. Picasa Importer) and click the “Create” button.
+     Your credentials will be displayed in a popup. Copy them to a safe place.`
+
+	fmt.Fprintf(os.Stderr, "Usage of %s:\n", os.Args[0])
+	flag.PrintDefaults()
+	fmt.Fprintf(os.Stderr, "\n%s\n\n", credentialSteps)
+}
+
 func main() {
+	flag.Usage = picasaUsage
 	dsFlags := dataset.NewFlags()
 	flag.Parse()
 	httpClient = util.CachingHttpClient()