metrics

type HandlerWrapper ¶

type HandlerWrapper struct {
	// contains filtered or unexported fields
}

HandlerWrapper contains the data and logic needed to wrap an HTTP handler with another one that generates Prometheus metrics.

func (w *HandlerWrapper) Wrap(h http.Handler) http.Handler

type HandlerWrapperBuilder ¶

type HandlerWrapperBuilder struct {
	// contains filtered or unexported fields
}

HandlerWrapperBuilder contains the data and logic needed to build a new metrics handler wrapper that creates HTTP handlers that generate the following Prometheus metrics:

<subsystem>_request_count - Number of API requests sent.
<subsystem>_request_duration_sum - Total time to send API requests, in seconds.
<subsystem>_request_duration_count - Total number of API requests measured.
<subsystem>_request_duration_bucket - Number of API requests organized in buckets.

To set the subsystem prefix use the Subsystem method.

The duration buckets metrics contain an `le` label that indicates the upper bound. For example if the `le` label is `1` then the value will be the number of requests that were processed in less than one second.

The metrics will have the following labels:

method - Name of the HTTP method, for example GET or POST.
path - Request path, for example /api/clusters_mgmt/v1/clusters.
code - HTTP response code, for example 200 or 500.
apiservice - API service name, for example ocm-clusters-service.

To calculate the average request duration during the last 10 minutes, for example, use a Prometheus expression like this:

rate(api_outbound_request_duration_sum[10m]) / rate(api_outbound_request_duration_count[10m])

In order to reduce the cardinality of the metrics the path label is modified to remove the identifiers of the objects. For example, if the original path is .../clusters/123 then it will be replaced by .../clusters/-, and the values will be accumulated. The line returned by the metrics server will be like this:

     <subsystem>_request_count{code="200",method="GET",path="/api/clusters_mgmt/v1/clusters/-",
		apiservice="ocm-clusters-service"} 56

The meaning of that is that there were a total of 56 requests to get specific clusters, independently of the specific identifier of the cluster.

The value of the `code` label will be zero when sending the request failed without a response code, for example if it wasn't possible to open the connection, or if there was a timeout waiting for the response.

Note that setting this attribute is not enough to have metrics published, you also need to create and start a metrics server, as described in the documentation of the Prometheus library.

Don't create objects of this type directly; use the NewHandlerWrapper function instead.

func NewHandlerWrapper() *HandlerWrapperBuilder

func (b *HandlerWrapperBuilder) Build() (result *HandlerWrapper, err error)

func (b *HandlerWrapperBuilder) Path(value string) *HandlerWrapperBuilder

func (b *HandlerWrapperBuilder) Registerer(value prometheus.Registerer) *HandlerWrapperBuilder

func (b *HandlerWrapperBuilder) Subsystem(value string) *HandlerWrapperBuilder

api_inbound_request_count - Number of API requests sent.
api_inbound_request_duration_sum - Total time to send API requests, in seconds.
api_inbound_request_duration_count - Total number of API requests measured.
api_inbound_request_duration_bucket - Number of API requests organized in buckets.

type TransportWrapper ¶

type TransportWrapper struct {
	// contains filtered or unexported fields
}

TransportWrapper contains the data and logic needed to wrap an HTTP round tripper with another one that generates Prometheus metrics.

func (w *TransportWrapper) Wrap(transport http.RoundTripper) http.RoundTripper

type TransportWrapperBuilder ¶

type TransportWrapperBuilder struct {
	// contains filtered or unexported fields
}

TransportWrapperBuilder contains the data and logic needed to build a new metrics transport wrapper that creates HTTP round trippers that generate the following Prometheus metrics:

<subsystem>_request_count - Number of API requests sent.
<subsystem>_request_duration_sum - Total time to send API requests, in seconds.
<subsystem>_request_duration_count - Total number of API requests measured.
<subsystem>_request_duration_bucket - Number of API requests organized in buckets.

To set the subsystem prefix use the Subsystem method.

The duration buckets metrics contain an `le` label that indicates the upper bound. For example if the `le` label is `1` then the value will be the number of requests that were processed in less than one second.

The metrics will have the following labels:

method - Name of the HTTP method, for example GET or POST.
path - Request path, for example /api/clusters_mgmt/v1/clusters.
code - HTTP response code, for example 200 or 500.
apiservice - API service name, for example ocm-clusters-service.

To calculate the average request duration during the last 10 minutes, for example, use a Prometheus expression like this:

rate(api_outbound_request_duration_sum[10m]) / rate(api_outbound_request_duration_count[10m])

In order to reduce the cardinality of the metrics the path label is modified to remove the identifiers of the objects. For example, if the original path is .../clusters/123 then it will be replaced by .../clusters/-, and the values will be accumulated. The line returned by the metrics server will be like this:

     <subsystem>_request_count{code="200",method="GET",path="/api/clusters_mgmt/v1/clusters/-",
		apiservice="ocm-clusters-service"} 56

The meaning of that is that there were a total of 56 requests to get specific clusters, independently of the specific identifier of the cluster.

The value of the `code` label will be zero when sending the request failed without a response code, for example if it wasn't possible to open the connection, or if there was a timeout waiting for the response.

Note that setting this attribute is not enough to have metrics published, you also need to create and start a metrics server, as described in the documentation of the Prometheus library.

Don't create objects of this type directly; use the NewTransportWrapper function instead.

func NewTransportWrapper() *TransportWrapperBuilder

func (b *TransportWrapperBuilder) Build() (result *TransportWrapper, err error)

func (b *TransportWrapperBuilder) Path(value string) *TransportWrapperBuilder

func (b *TransportWrapperBuilder) Registerer(value prometheus.Registerer) *TransportWrapperBuilder

func (b *TransportWrapperBuilder) Subsystem(value string) *TransportWrapperBuilder

api_outbound_request_count - Number of API requests sent.
api_outbound_request_duration_sum - Total time to send API requests, in seconds.
api_outbound_request_duration_count - Total number of API requests measured.
api_outbound_request_duration_bucket - Number of API requests organized in buckets.