Merge pull request realpython#62 from spulec/master

Add Additional Fabric Example

Author: Kenneth Reitz

docs/scenarios/admin.rst

@@ -10,31 +10,56 @@ fabric is more focused on application level tasks such as deployment.
 
 Install Fabric:
 
-::
+.. code-block:: bash
 
     $ pip install fabric
 
-The following code will ssh into both of our servers, cd to our project
-directory, activate the virtual environment, pull the newest codebase,
-and restart the application server.
+The following code will create two tasks that we can use: ``memory_usage`` and
+``deploy``. The former will output the memory usage on each machine. The
+latter will ssh into each server, cd to our project directory, activate the
+virtual environment, pull the newest codebase, and restart the application
+server.
 
 ::
 
     from fabric.api import cd, env, prefix, run, task
 
     env.hosts = ['my_server1', 'my_server2']
 
+    @task
+    def memory_usage():
+        run('free -m')
+
     @task
     def deploy():
         with cd('/var/www/project-env/project'):
             with prefix('. ../bin/activate'):
                 run('git pull')
                 run('touch app.wsgi')
 
-With the previous code saved in a file named fabfile.py, we merely need to run
-the following command to deploy our application to both of our servers.
+With the previous code saved in a file named fabfile.py, we can check memory
+usage with:
 
-::
+.. code-block:: bash
+
+    $ fab memory_usage
+    [my_server1] Executing task 'memory'
+    [my_server1] run: free -m
+    [my_server1] out:              total     used     free   shared  buffers   cached
+    [my_server1] out: Mem:          6964     1897     5067        0      166      222
+    [my_server1] out: -/+ buffers/cache:     1509     5455
+    [my_server1] out: Swap:            0        0        0
+
+    [my_server2] Executing task 'memory'
+    [my_server2] run: free -m
+    [my_server2] out:              total     used     free   shared  buffers   cached
+    [my_server2] out: Mem:          1666      902      764        0      180      572
+    [my_server2] out: -/+ buffers/cache:      148     1517
+    [my_server2] out: Swap:          895        1      894
+
+and we can deploy with:
+
+.. code-block:: bash
 
     $ fab deploy