ApplicationInsights blocks scripts from exiting

[richardspence]

I'm using application insights to instrument a gulp build script, and it blocks gulp from exiting when started.

I manually need to run client.dispose() after each entry task's exit point (on finish, on error) and the error handlers of all the dependencies.

I'm guessing the architecture has a log collector agent that is running in the background. It would be good to have a synchronous mode where that's not created, and flush the events on process exit.

[OsvaldoRosado]

Linking some related issues: #54, #220, #310, #331

Are you calling start()? This initializes quite a few background loops (such as for autocollection of cpu and memory usage). In scenarios like this I would suggest not calling start() to disable these background loops. You'll also need to actively disable disk retry caching, as this is known to impact script exit (see https://stackoverflow.com/a/49441135 for an example)

Without start() or disk retry caching, the primary thing that's going to delay your process exit is the loop for batching events (though this should be only a delay and not a permanent no-exit). If the delay isn't acceptable (default 15 seconds), and you are firing very few telemetry events(batching isn't necessary), you can disable it in the configuration either by changing client.config.maxBatchSize or client.config.maxBatchInterval. If you do need batching, the easiest solution here is call client.flush

[OsvaldoRosado]

As an extra note, it's definitely a bug if this SDK keeps you from exiting after all batched items have been sent (when no extra collection features are enabled), rather than a missing mode. This should be covered in this test, but perhaps it's missing something:

https://github.com/Microsoft/ApplicationInsights-node.js/blob/develop/Tests/js/endToEnd.js

[richardspence]

Yes I was using client.start() as I thought it was required.

Changing my configuration to this, solves my issue:

const appInsights = require('applicationinsights');
appInsights.setup("...")
    .setAutoCollectExceptions(true)
    .setAutoCollectConsole(true)

appInssights.defaultClient.config.maxBatchIntervalMs = 100;

Thanks!