Metrics Service

This library is designed to help speed up the process of creating OpenTelemetry Metrics and services with Microsoft's Dependency Injection.

Features

• Uses decorated Enums to define Metrics.
• Supports the creation of Counter, Up/Down, and Histogram metrics (you will need to define your own boundaries).
• Can create an IDisposable to handle Up/Down counters that will increase the count on creation and decrease it when Dispose() is called.
• Can register IMetricsService<EnumType, MetricValueType> services by simply calling AddMetricsService< EnumType >(). Can automatically register the metrics in OpenTelemetry by passing true as the parameter.
• Can have mandatory tags defined as well as create Metrics and Meters with tags already specified.
• Overridable functions in Service for custom implementations.

Example

Setup

Metric Enumeration:

/// <summary>
/// Test Metric
/// </summary>
[MeterDefinition("My.Meter.Namespace", "beta-1.0", RequiredTagNames = ["Tag1", "Tag2"])]
[MetricTag("MyMetricTag", "MyMetricTagValue")]
public enum MyMetricLong
{
    [MetricDefinition(InstrumentType.Counter, "CounterMetric", "Test Counter Metric", Unit = "MadeUpUnit", RequiredTagNames = ["CounterName"])]
    CounterMetric,
 
    [MetricDefinition(InstrumentType.UpDownCounter, "UpDownMetric", "Test Up/Down Metric")]
    [MetricTag("CounterName", "UpDownMetric")]
    UpDownMetric,
 
    [MetricDefinition(InstrumentType.Histogram, "HistogramMetric", "Test Histogram Metric")]
    HistogramMetric,
 
    [MetricDefinition(InstrumentType.Counter, "EverythingCounterMetric", "Test Everything Counter Metric", RequiredTagNames = ["CounterName"])]
    [MetricDefinition(InstrumentType.UpDownCounter, "EverythingUpDownMetric", "Test Everything Up/Down Metric")]
    [MetricDefinition(InstrumentType.Histogram, "EverythingHistogramMetric", "Test Everything Histogram Metric")]
    [MetricTag("EverythingMetric", true)]
    EverythingMetric
}

To add the metrics to DI:

services.AddMetricsService<MyMetricLong>(true)

Use

Here is an example of using DI to inject the metric service.

public class MyService(
    IMetricsService<MyMetricLong> metricsService // Short for IMetricsService<MyMetricLong, long
        )
{
    public void SomeMethod()
    {
        /* Do Stuff */
 
        // Inc Counter
        metricsService.IncCounter( // Call assumes the increment amount is 1 since not provided in this variation of IncCounter().
            MyMetricLong.CounterMetric, // Metric Identifier (only has one instrument so we don't need to specify the instrument in this case.)
            new KeyValuePair<string, object?>("Tag1", "Required Tag 1 Value"), // Required based on MeterDefinitionAttribute on MyMetricLong
            new KeyValuePair<string, object?>("Tag2", "Required Tag 2 Value"), // Required based on MeterDefinitionAttribute on MyMetricLong
            new KeyValuePair<string, object?>("CounterName", "My Counter Name") // Required based on MetricDefinitionAttribute on MyMetricLong.CounterMetric
            );
 
        /* Do More Stuff */
    }
 
    public void AnotherMethod()
    {
        using var counterDisposable = metricsService.CreateDisposableCounter( // Call Increments the counter by one and returns an IDisposable that will decrement the counter when .Dispose() is called.
            MyMetricLong.EverythingMetric, // Metric Identifier, which defines all 3 instruments! Since this will both increase and decrease the counter, it must be an Up/Down Counter so that is what will be used.
            new KeyValuePair<string, object?>("Tag1", "Required Tag 1 Value"), // Required based on MeterDefinitionAttribute on MyMetricLong
            new KeyValuePair<string, object?>("Tag2", "Required Tag 2 Value") // Required based on MeterDefinitionAttribute on MyMetricLong
            );
 
 
        /* Do Stuff */
 
        /* counterDisposable.Dispose() called when variable goes out of scope.  This decreases the counter by 1. */
    }
}

Results

• Add a new Meter called "My.Meter.Namespace" as Version 'beta-1.0' and tag 'MyMetricTag='MyMetricTagValue'. All Metrics will require tags named 'Tag1' and 'Tag2' (or a MissingRequiredTagsException will be thrown).
• Add services in DI called IMetricsService< MyMetricLong > and IMetricsService< MyMetricLong, long >.

Note: IMetricsService< MyMetricLong > is only created when the default MetricDataType is used. The MeterDefinitionAttribute can create Metrics that use any of the supported metric types (int, long, decimal, double, float, or byte).

• Create the following Metrics:

Name	Description	Created With Tags	Required Tags
my.meter.namespace.counterMetric	Test Counter Metric	"CounterName"="UpDownMetric"	"Tag1", "Tag2", "CounterName"
my.meter.namespace.upDownMetric	Test Up/Down Metric		"Tag1", "Tag2"
my.meter.namespace.histogramMetric	Test Histogram Metric		"Tag1", "Tag2"
my.meter.namespace.everythingCounterMetric	Test Everything Counter Metric	"EverythingMetric"=true	"Tag1", "Tag2", "CounterName"
my.meter.namespace.everythingUpDownMetric	Test Everything Up/Down Metric	"EverythingMetric"=true	"Tag1", "Tag2"
my.meter.namespace.everythingHistogramMetric	Test Everything Histogram Metric	"EverythingMetric"=true	"Tag1", "Tag2"

Note: Name, be default, combines the Meter name with the Metric Name Suffix using dot-notation and camelCase.

Overrides

MetricsService<,> can be used as a base class and have various parts of the process customized.

Name	Description
InitializeMetricInstruments	Called by Constructor to create Instruments. By default, this loops through all the Enum values, loads the Attributes, and calls AddMetricInstrumentName() and CreateMetricInstrument() for each.
AddMetricInstrumentName	Add Metric Instrument's Name to the provided MetricInstrumentInfo and return the updated data.
CreateMetricInstrument	Takes the Instrument Data, Creates the Instrument(s) and adds them to the Instruments ConcurrentDictionary.
AssertAmount	Used to validate the amount sent to the Inc/Dec calls (Instrument information is provided).