Merge branch '16470-activesupport52-dependency' into production-master

[arvados.git] / README.md

diff --git a/README.md b/README.md
index 04ed0b0620a7c73254eb3d02a59500acaabb8dbe..510ae817e9b14d5e93b66faefa47d501d3e6c143 100644 (file)
--- a/README.md
+++ b/README.md
@@ -104,6 +104,19 @@ Credentials can be managed at the connection level, as shown, or supplied on a p
 
 For server-to-server interactions, like those between a web application and Google Cloud Storage, Prediction, or BigQuery APIs, use service accounts.
 
+As of version 0.8.3, service accounts can be configured using
+[Application Default Credentials][1], which rely on the credentials being
+available in a well-known location.  If the credentials are not present
+and it's being used on a Compute Engine VM,  it will use the VM's default credentials.
+
+```ruby
+client.authorization = :google_app_default  # in a later version, this will become the default
+client.authorization.fetch_access_token!
+client.execute(...)
+```
+
+This is simpler API to use than in previous versions, although that is still available:
+
 ```ruby
 key = Google::APIClient::KeyUtils.load_from_pkcs12('client.p12', 'notasecret')
 client.authorization = Signet::OAuth2::Client.new(
@@ -123,6 +136,8 @@ in the credentials. Detailed instructions on how to enable delegation for your d
 
 The API client can automatically retry requests for recoverable errors. To enable retries, set the `client.retries` property to
 the number of additional attempts. To avoid flooding servers, retries invovle a 1 second delay that increases on each subsequent retry.
+In the case of authentication token expiry, the API client will attempt to refresh the token and retry the failed operation - this
+is a specific exception to the retry rules.
 
 The default value for retries is 0, but will be enabled by default in future releases.
 
@@ -135,7 +150,7 @@ Example:
 
 ```ruby
 client = Google::APIClient.new
-urlshortener = client.discovered_api('urlshortner')
+urlshortener = client.discovered_api('urlshortener')
 
 batch = Google::APIClient::BatchRequest.new do |result|
     puts result.data
@@ -199,3 +214,5 @@ See the full list of [samples on Github](https://github.com/google/google-api-ru
 ## Support
 
 Please [report bugs at the project on Github](https://github.com/google/google-api-ruby-client/issues). Don't hesitate to [ask questions](http://stackoverflow.com/questions/tagged/google-api-ruby-client) about the client or APIs on [StackOverflow](http://stackoverflow.com).
+
+[1]: https://developers.google.com/accounts/docs/application-default-credentials