ℹ️  SignalFx was acquired by Splunk in October 2019. See Splunk SignalFx for more information.

⚠️ Deprecation Notice

The SignalFx C# Azure Function Wrapper is deprecated and will reach End of Support on Jan 20, 2024. After that date, this repository will be archived and no longer receive updates. Until then, only critical security fixes and bug fixes will be provided.

SignalFx C# Azure Function Wrapper

SignalFx C# Azure Function Wrapper.

Usage

The SignalFx C# Azure Function Wrapper is a wrapper around an Azure Function, used to instrument execution of the function and send metrics to SignalFx.

Install via NuGet

Add the following package reference to your .csproj or function.proj

  <PackageReference Include="signalfx-azure-functions" Version="1.0.0"/>

Using the Metric Wrapper

Create a MetricWrapper with the ExecutionContext Wrap your code in try-catch-finally, disposing of the wrapper finally.

using azurefunctioncsharp

...

    [FunctionName("HttpTrigger")]
		public static IActionResult Run([HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)]HttpRequest req, TraceWriter log, ExecutionContext context)
        {
            log.Info("C# HTTP trigger function processed a request.");
            MetricWrapper wrapper = new MetricWrapper(context);
            try { 
                ...
                // your code
                ...
                return ResponseObject
            } catch (Exception e) {
              wrapper.Error();
            } finally {
              wrapper.Dispose();
            }

        }

Configuring the ingest endpoint

By default, this function wrapper will send to the us0 realm. If you are not in this realm you will need to set the SIGNALFX_API_HOSTNAME environment variable to the correct realm ingest endpoint (https://ingest.{REALM}.signalfx.com). To determine what realm you are in, check your profile page in the SignalFx web application (click the avatar in the upper right and click My Profile).

Environment Variable

Set the Azure Function environment variables as follows:

1. Set authentication token:

 SIGNALFX_AUTH_TOKEN=signalfx token

2. Optional parameters available:

 SIGNALFX_API_HOSTNAME=[ingest.us0.signalfx.com]
 SIGNALFX_API_PORT=[443]
 SIGNALFX_API_SCHEME=[https]
 SIGNALFX_SEND_TIMEOUT=milliseconds for signalfx client timeout [2000]

Metrics and dimensions sent by the wrapper

The Azure Function Wrapper sends the following metrics to SignalFx:

Metric Name	Type	Description
azure.function.invocations	Counter	Count number of function invocations
azure.function.errors	Counter	Count number of errors from underlying function
azure.function.duration	Gauge	Milliseconds in execution time of underlying function

The function wrapper adds the following dimensions to all data points sent to SignalFx:

Dimension	Description
azure_region	Azure Region where the function is executed
azure_function_name	Name of the function
azure_resource_name	Name of the function app where the function is running
function_wrapper_version	SignalFx Function Wrapper qualifier (e.g. signalfx-azurefunction-0.0.11)
is_Azure_Function	Used to differentiate between Azure App Service and Azure Function metrics
metric_source	The literal value of 'azure_function_wrapper'

Sending a custom metric from the Azure Function

using com.signalfuse.metrics.protobuf;

// construct a data point
DataPoint dp = new DataPoint();

// use Datum to set the value
Datum datum = new Datum();
datum.intValue = 1;

// set the name, value, and metric type on the datapoint

dp.metric = "metric_name";
dp.metricType = MetricType.GAUGE;
dp.value = datum;

// add custom dimension
Dimension dim = new Dimension();
dim.key = "applicationName";
dim.value = "CoolApp";
dp.dimensions.Add(dim);

// send the metric
MetricSender.sendMetric(dp);

Testing locally.

1. Follow the Azure instructions to run functions locally https://docs.microsoft.com/en-us/azure/azure-functions/functions-reference-csharp

2. Install as shown above by adding the dependency to function.proj or .csproj

License

Apache Software License v2. Copyright © 2014-2017 SignalFx