title: Defining a correct requirements.txt file
body: <p>I have developed a Flask web application that works on my local computer but which I am now trying to port onto the web (via IBM Bluemix). My first attempt to do so was unsuccessful. The error message I receive is:</p>
  
  <p><code>Server error, status code: 400, error code: 170001, message: Staging error: no available stagers</code></p>
  
  <p>When I check the log files with <code>cf logs myapp --recent</code> I find:</p>
  
  <pre><code>2015-11-08T15:34:15.92-0500 [STG/35]     OUT -----&gt; Downloaded app package (72K)
  2015-11-08T15:34:19.98-0500 [STG/35]     OUT -----&gt; Downloaded app buildpack cache (39M)
  2015-11-08T15:34:24.82-0500 [STG/0]      OUT -------&gt; Buildpack version 1.3.1
  2015-11-08T15:34:40.57-0500 [STG/0]      OUT -----&gt; Installing dependencies with pip
  2015-11-08T15:34:41.54-0500 [STG/0]      OUT        You are using pip version 6.1.0.dev0, however version 7.1.2 is available.
  2015-11-08T15:34:41.54-0500 [STG/0]      OUT        You should consider upgrading via the 'pip install --upgrade pip' command.
  2015-11-08T15:34:41.56-0500 [STG/0]      OUT        Collecting flask.ext.wtf (from -r requirements.txt (line 2))
  2015-11-08T15:34:41.88-0500 [STG/0]      OUT          Could not find a version that satisfies the requirement flask.ext.wtf (from -r requirements.txt (line 2)) (from versions: )
  2015-11-08T15:34:41.88-0500 [STG/0]      OUT          No matching distribution found for flask.ext.wtf (from -r requirements.txt (line 2))
  2015-11-08T15:34:41.96-0500 [STG/0]      OUT Staging failed: Buildpack compilation step failed
  2015-11-08T15:34:41.97-0500 [STG/0]      ERR 
  2015-11-08T15:34:42.67-0500 [API/2]      ERR encountered error: App staging failed in the buildpack compile phase
  2015-11-08T15:35:37.75-0500 [API/3]      OUT Updated app with guid b580bb64-4415-4bb4-8fd1-1e4d3de4f7d9 ({"name"=&gt;"cultural-insight", "memory"=&gt;128, "environment_json"=&gt;"PRIVATE DATA HIDDEN"})
  2015-11-08T15:35:49.95-0500 [API/3]      OUT Updated app with guid b580bb64-4415-4bb4-8fd1-1e4d3de4f7d9 ({"state"=&gt;"STOPPED"})
  2015-11-08T15:35:52.41-0500 [DEA/113]    OUT Got staging request for app with id b580bb64-4415-4bb4-8fd1-1e4d3de4f7d9
  2015-11-08T15:35:52.47-0500 [API/0]      ERR exception handling first response Staging error: failed to stage application:
  2015-11-08T15:35:52.47-0500 [API/0]      ERR Not enough memory resources available
  2015-11-08T15:50:52.42-0500 [API/0]      ERR encountered error: Staging error: failed to stage application: staging had already been marked as failed, this could mean that staging took too long
  </code></pre>
  
  <p>The problem appears to be that <code>pip</code> can't find <code>Flask-WTF</code>, which I need for my application to work.</p>
  
  <p>I installed Flask-WTF on my local machine with <code>pip install Flask-WTF</code>. The contents of <code>requirements.txt</code>, which the builder ingests while setting up, is simply:</p>
  
  <p><code>Flask==0.10.1
  Flask-WTF</code></p>
  
  <p>In particular, I am unsure why pip is asking for <code>flask.ext.wtf</code>? Additionally it is troubling me that the application says it is limited to 128 MB, when I bumped it up to 512 MB.</p>
  
  <p>Altogether, I'm not sure what's going on. How do I resolve this issue? The full source code is <a href="https://github.com/ResidentMario/py-events" rel="nofollow">here</a>.</p>