title: how to specify a variable/parameter in my logic app's arm template?
body: <p>I am creating an Arm template for a logic app. This logic app needs to delete some old entries in azure table (say 10 or 20 days old).</p>
  
  <p>In my arm template, if I do this, it works.</p>
  
  <pre><code>"queries": {
              "$filter": "Timestamp le datetime'@{addDays(utcNow(),-31)}'"
    }
  </code></pre>
  
  <p>But ideally I want to do this:</p>
  
  <pre><code>"queries": {
              "$filter": "Timestamp le datetime'@{addDays(utcNow(),parameters('RetainDay'))}'"
     }
  </code></pre>
  
  <p>Basically use a parameter to control the amount of days to check. I define this parameter as:</p>
  
  <pre><code> "parameters": {
      "RetainDay": {
        "type": "int"
      }
    }
  </code></pre>
  
  <p>When I deploy this, the parameters('RetainDay') isn't replaced to the parameter value. Instead it just stays same as:</p>
  
  <pre><code>Timestamp le datetime'@{addDays(utcNow(),parameters('RetainDay')
  </code></pre>
  
  <p>So I must be using the wrong syntax.</p>
  
  <p>Can someone point it out?</p>