Example: host.json Conflict Resolution¶

This example shows how host-level log policy can suppress application logs and how to fix it safely.

Why This Matters¶

setup_logging(level=logging.INFO) can still appear broken if host.json is stricter.

Common symptom:

INFO logs missing in Azure or Core Tools output.
WARNING and above still visible.

Baseline Application Setup¶

import logging
from azure_functions_logging import get_logger, setup_logging

setup_logging(level=logging.INFO, format="json")
logger = get_logger(__name__)

logger.info("info event")
logger.warning("warning event")

Conflicting host.json¶

{
  "logging": {
    "logLevel": {
      "default": "Warning"
    }
  }
}

With this host policy:

warning events appear.
info events are suppressed.

Corrected host.json¶

{
  "logging": {
    "logLevel": {
      "default": "Information"
    }
  }
}

Now both info and warning events are visible.

Function-Specific Override Pattern¶

You can keep strict defaults and open specific functions:

{
  "logging": {
    "logLevel": {
      "default": "Warning",
      "Function.OrdersHttp": "Information"
    }
  }
}

This is useful when one function needs richer diagnostics.

End-to-End Function Example¶

import azure.functions as func
from azure_functions_logging import get_logger, inject_context, setup_logging

setup_logging(format="json")
logger = get_logger("orders")

app = func.FunctionApp()


@app.route(route="orders")
def orders(req: func.HttpRequest, context: func.Context) -> func.HttpResponse:
    inject_context(context)
    logger.info("orders request started")
    logger.warning("orders validation warning")
    return func.HttpResponse("ok")

If INFO does not appear, inspect host.json first.

Validation Checklist¶

Verify app setup level.
Verify host default level.
Verify function-specific overrides.
Verify deployment uses expected host.json.
Verify output sink query is not filtering low levels.

Safety Guidelines¶

Avoid globally setting very low host levels in high-volume workloads.
Prefer per-function overrides when targeted diagnostics are needed.
Keep JSON logs structured for efficient filtering.

Troubleshooting Matrix¶

App Level	Host Default	INFO Visible?
INFO	Warning	No
INFO	Information	Yes
DEBUG	Warning	No
WARNING	Warning	Yes

Observability Recommendation¶

Use this pairing for production:

App setup: setup_logging(level=logging.INFO, format="json")
Host default: Information
Dependency logger overrides: WARNING

This keeps signal quality high while preserving troubleshooting depth.