title: Variable interpolation inside Map directive
body: <p>I am trying to map a variable inside the http directive in Nginx.</p>
  
  <p>When left alone, the variable alone gets expanded, if I add anything else to the string the expansion stops working. </p>
  
  <pre><code>http {
  
      map $host $foo {
          #default "$host";                    # - this works fine and returns 'localhost' 
          default "This is my host: $host";    # - THIS DOESN'T WORK
      }
  
      server {
  
          location / {
              echo $foo;
          }
  
      }
  
  }
  </code></pre>
  
  <p>Do you have any suggestions to make the expansion work inside the map?</p>