dynatrace-metric-utils-go

dynatrace-metric-utils-go

Utility for preparing communication with the Dynatrace Metrics API v2.

Usage

An example for how to use this library can be found in example/main.go. It shows how to create metrics lines that can be sent to a Dynatrace metrics ingest endpoint using an HTTP client library.

Preparation

The standard workflow consists of creating NormalizedDimensionList objects that contain Dimensions. There is no upper limit to how many NormalizedDimensionLists can be used, but we found that the following schema covers most use cases. In this schema we use three lists, all of which are optional.

• The first list of dimensions are default dimensions, which contain information that can be shared between multiple metrics, e.g. the hostname of the machine.
• The second NormalizedDimensionList contains dimensions that are specific to a certain metric, e.g. the information whether or not a HTTP request was successful.
• The third list are the Dimensions created by the OneAgent metadata enricher, which is described further below.

The serialization function accepts a merged NormalizedDimensionList which can be acquired using the dimensions.MergeLists function. Dimensions in lists passed further right with the same (normalized) dimension keys overwrite dimensions passed in lists further left.

Note that the MergeLists function must be called every time a new dimension is added to any of the lists!

Metric line creation

After the creation of the dimensions, the metric package allows for the creation of metric lines. To do so, use the following pattern:

m, err := metric.NewMetric(
  "the_metric_key",
  metric.WithPrefix("prefix"),
  metric.WithIntCounterValueDelta(30),
  metric.WithDimensions(merged),
  metric.WithCurrentTime(),
)
// handle potential errors... 
serialized, err := m.Serialize()
// handle potential errors... 
fmt.Println(serialized)

The serialized data point is ready to be sent to a Dynatrace metrics ingest endpoint using an HTTP client library.

Metric line creation options

• WithPrefix: set a prefix that will be prepended to the metric key.
• WithDimensions: sets a NormalizedDimensionList for serialization. Lists should be de-duplicated and combined before being passed to this function by running them through the MergeLists function. If only one list is present, MergeLists will still do the de-duplication.
• WithIntCounterValueDelta / WithFloatCounterValueDelta: sets a single value that is serialized as count,delta=<value>.
• WithIntGaugeValue / WithFloatGaugeValue: sets a single value that is serialized as gauge,<value>.
• WithIntSummaryValue / WithFloatSummaryValue: sets min, max, sum and count values that are serialized as gauge,min=<min>,max=<max>,sum=<sum>,count=<count>.
• WithTimestamp: sets a specific time.Time object on the metric that will be used to create the timestamp on the metric line.
• WithCurrentTime: sets the current timestamp to the Metric object.

A metric line can be serialized only if it has a valid name (including the optional prefix) and exactly one Value attribute set. Timestamps and dimensions are optional.

OneAgent Enrichment

When using the GetOneAgentMetadata method in the oneagentenrichment package, the library will connect to the Dynatrace OneAgent, if installed, and retrieve dimensions with process and host identifiers. More information on the underlying feature that is used by the library can be found in the Dynatrace documentation.

Due to how OneAgent metadata is read and how Go reads files, it is at the moment not possible to read metadata on Unix/Linux systems. OneAgent enrichment for Go therefore only works on Windows hosts at the moment. On Unix/Linux hosts, an empty list will be returned without any errors, if it is called nevertheless. The same applies if no OneAgent is installed on the monitored host.

To acquire a list of OneAgent metadata dimensions, use the following method:

oneAgentDimensions := oneagentenrichment.GetOneAgentMetadata()

These dimensions can then be passed to the MergeLists function as shown in the example.

Common constants

The library also provides constants that might be helpful in the projects consuming this library.

To access the constants, call the respective methods from the apiconstants package:

defaultOneAgentEndpoint := apiconstants.GetDefaultOneAgentEndpoint()

Currently available constants are:

• the default local OneAgent metric API endpoint (GetDefaultOneAgentEndpoint())
• the limit for how many metric lines can be ingested in one request (GetPayloadLinesLimit())