"Metric Namespace" not working for metrics sent to Azure Monitor

[fyayc-bue]

• monitor.opentelemetry.exporter:
• 1.0.0.b36:
• all:
• all:

Describe the bug
No way to define a custom "Metric Namespace" different from 'azure.applicationinsights' when using the
azure.monitor.opentelemetry.exporter.AzureMonitorMetricExporter from azure-monitor-opentelemetry-exporter==1.0.0.b36.

To Reproduce
Steps to reproduce the behavior:

1. Set up telemetry to Azure Monitor
2. Run the testcode below to publish one value (1.1)
3. Verify transmission and storage in Azure Monitor. Metric namespace 'azure.applicationinsights' contains your meter and the value 1.1.
4. Provide a namespace='xyz' to your telemetry setup (see code)
5. Publish a second value using the configuration with namespace='xyz' (1.2)
6. Check transmission and storage in Azure Monitor. Metric Namespace 'azure.applicationinsights' still contains three entries. ![Image]Log-based metrics, Application Insights standard metrics, azure.applicationinsights instead of 4 including the new namespace 'xyz'.

Expected behavior
azure-monitor-opentelemetry-exporter sends the namespace and Azure Monitor respects this.
The Azure Monitor allows for selection of namespace 'xyz' when provided.

Screenshots

Additional context

Code to reproduce the issue:

import time

from opentelemetry.sdk.metrics.export import PeriodicExportingMetricReader
from opentelemetry.sdk.metrics import MeterProvider
from opentelemetry.sdk.resources import Resource

from azure.monitor.opentelemetry.exporter import AzureMonitorMetricExporter

APPLICATIONINSIGHTS_CONNECTION_STRING = "InstrumentationKey=fb2...380;IngestionEndpoint=https://germanywestcentral-1.in.applicationinsights.azure.com/;LiveEndpoint=https://germanywestcentral.livediagnostics.monitor.azure.com/;ApplicationId=00d...5b"

namespace = ""
# namespace = "xyz"

if len(namespace) == 0:
    telemetry = AzureMonitorMetricExporter.from_connection_string(
        APPLICATIONINSIGHTS_CONNECTION_STRING,
    )
else:
    telemetry = AzureMonitorMetricExporter.from_connection_string(
        APPLICATIONINSIGHTS_CONNECTION_STRING,
        namespace=namespace + ".c.ns",
    )

reader = PeriodicExportingMetricReader(telemetry)

resource = Resource(
    attributes={
        "service.namespace": "svc.ns",
        "metric.namespace": "metric.ns",
        "service.name": f"svc.name"}
)

if len(namespace) == 0:
    meter_provider = MeterProvider(metric_readers=[reader])
    value = 1.1
else:
    meter_provider = MeterProvider(metric_readers=[reader], resource=resource)
    value = 1.2

telemeter = meter_provider.get_meter(f"sample.meter" + namespace)
tm = telemeter.create_gauge("sample.gauge" + namespace)

print(f"Sending value {value} {namespace if len(namespace) > 0 else ''}")
tm.set(value)
telemetry.force_flush()

telemetry.shutdown(1000)
print("Done")

[github-actions]

Hi @fyayc-bue, I'm an AI Support assistant here to help with your issue. While the Azure SDK team reviews your request, I wanted to provide some possible tips and documentation that might help you in the meantime.

• The recent 1.0.0b18 release removed support for a custom metric namespace (#32897), so metrics are always sent under the default namespace.
• This means that providing a custom namespace (e.g. "xyz") to AzureMonitorMetricExporter will not affect the namespace where the metrics appear.
• For guidance on using the exporter, please refer to the README documentation.

The Azure SDK team will respond to your issue shortly. I hope these suggestions are helpful in the meantime. If this comment helped you, please give it a 👍. If the suggestion was not helpful or incorrect, please give it a 👎. Your feedback helps us improve!

[fyayc-bue]

Thanks to the link provided by the AI Support, I was able to find the missing piece:

Setting the environment variable 'APPLICATIONINSIGHTS_METRIC_NAMESPACE_OPT_IN' to 'true' led to the desired result.

os.environ["APPLICATIONINSIGHTS_METRIC_NAMESPACE_OPT_IN"] = "true"

Documentation of the change that introduced the feature by @lzchen, thank you!