Host.json basics

At the root of an application is a metadata file that describes the global configuration of the host serving the different functions.

Configuring timeout

Timeouts allow the host to determine when the function will time out.

On a Consumption plan, the valid values are between 1 second (00:00:01) and 10 minutes (00:10:00). On an App Service Plan, any interval can be used including null. Setting it to null will have it wait indefinitely.

{
    "functionTimeout": "00:05:00"
}

Configuring queues

Functions that depend on queues can have the behavior of the queues customized.

Among the different possibilities, it's possible to set a polling interval, retry interval, as well as the size of the batch of messages to process in parallel.

{
  "queues": {
    // Interval in milliseconds
    "maxPollingInterval": 2000,
    // Time between calls/retries
    "visibilityTimeout": "00:00:30",
    //Maximum of 32
    "batchSize": 16
  }
}

Read more

For the full range of options, look up the complete documentation of host.json.