tools/android/loading Switch the GCE worker to pull queues

tools/android/loading/gce/README.md

Index: tools/android/loading/gce/README.md
diff --git a/tools/android/loading/gce/README.md b/tools/android/loading/gce/README.md
index 2bbd06b7c624175152e8fdb4886606376c959063..825f507841b9a08a8e5e7b9e17d22d762f149b00 100644
--- a/tools/android/loading/gce/README.md
+++ b/tools/android/loading/gce/README.md
@@ -32,15 +32,15 @@ gcloud compute instances create clovis-tracer-1 \
  --machine-type n1-standard-1 \
  --image ubuntu-14-04 \
  --zone europe-west1-c \
- --scopes cloud-platform \
- --metadata cloud-storage-path=$CLOUD_STORAGE_PATH,auto-start=true \
+ --scopes cloud-platform,https://www.googleapis.com/auth/cloud-taskqueue \
+ --metadata cloud-storage-path=$CLOUD_STORAGE_PATH,taskqueue_tag=some_tag \
  --metadata-from-file \
      startup-script=$CHROMIUM_SRC/tools/android/loading/gce/startup-script.sh
 ```
 
 **Note:** To start an instance without automatically starting the app on it,
-remove the `--metadata auto-start=true` argument. This can be useful when doing
-iterative development on the instance, to be able to restart the app manually.
+add a `auto-start=false` metadata. This can be useful when doing iterative
+development on the instance, to be able to restart the app manually.
 
 This should output the IP address of the instance.
 Otherwise the IP address can be retrieved by doing:
@@ -60,24 +60,9 @@ gcloud compute instances get-serial-port-output clovis-tracer-1
 
 ## Use the app
 
-Check that `http://<instance-ip>:8080/test` prints `hello` when opened in a
-browser.
-
-To send a list of URLs to process:
-
-```shell
-curl -X POST -d @urls.json http://<instance-ip>:8080/set_tasks
-```
-
-where `urls.json` is a JSON dictionary with the keys:
-
-*   `urls`: array of URLs
-*   `repeat_count`: Number of times each URL will be loaded. Each load of a URL
-    generates a separate trace file. Optional.
-*   `emulate_device`: Name of the device to emulate. Optional.
-*   `emulate_network`: Type of network emulation. Optional.
-
-You can follow the progress at `http://<instance-ip>:8080/status`.
+Create tasks from the associated AppEngine application, see [documentation][3].
+Make sure the `taskqueue_tag` of the AppEngine request matches the one of the
+ComputeEngine instances.
 
 ## Stop the app in the cloud
 
@@ -101,6 +86,14 @@ source env/bin/activate
 pip install -r $CHROMIUM_SRC/tools/android/loading/gce/pip_requirements.txt
 ```
 
+The first time, you may need to get more access tokens:
+
+```shell
+gcloud beta auth application-default login --scopes \
+    https://www.googleapis.com/auth/cloud-taskqueue \
+    https://www.googleapis.com/auth/cloud-platform
+```
+
 Create a JSON file describing the deployment configuration:
 
 ```shell
@@ -115,7 +108,8 @@ cat >$CONFIG_FILE << EOF
   "project_name" : "$PROJECT_NAME",
   "cloud_storage_path" : "$CLOUD_STORAGE_PATH",
   "chrome_path" : "$CHROME_PATH",
-  "src_path" : "$CHROMIUM_SRC"
+  "src_path" : "$CHROMIUM_SRC",
+  "taskqueue_tag" : "some_tag"
 }
 EOF
 ```
@@ -123,12 +117,10 @@ EOF
 Launch the app, passing the path to the deployment configuration file:
 
 ```shell
-gunicorn --workers=1 --bind 127.0.0.1:8080 \
-    --pythonpath $CHROMIUM_SRC/tools/android/loading/gce \
-    'main:StartApp('\"$CONFIG_FILE\"')'
+python $CHROMIUM_SRC/tools/android/loading/gce/worker.py --config $CONFIG_FILE
 ```
 
-You can now [use the app][2], which is located at http://localhost:8080.
+You can now [use the app][2].
 
 Tear down the local environment:
 
@@ -138,3 +130,4 @@ deactivate
 
 [1]: https://cloud.google.com/sdk
 [2]: #Use-the-app
+[3]: ../frontend/README.md