Logging in Functions

Looks like by default functions log at the info level. To change the level you can use set the application setting AzureFunctionsJobHost__logging__LogLevel__Default to some other value like Error or Info.

If you want to disable adaptive sampling then that can be done in the host.json

  "version": "2.0",
  "extensions": {
    "queues": {
      "maxPollingInterval": "00:00:05"
  "logging": {
    "logLevel": {
      "default": "Information"
    "applicationInsights": {
      "samplingSettings": {
        "isEnabled": false
  "functionTimeout": "00:10:00"

In this example adaptive sampling is turned off so you get every log message.

A thing to note is that if you crank down logging to Error you won’t see the invocations at all in the portal but they’re still running.