New singletonreceivercreator

[a-thaler]

Description
Have a first implementation of a decorating receiver, which will activate a nested receiver on if it got selected as leader in a leader election mechanism, see also https://github.com/kyma-project/telemetry-manager/blob/main/docs/contributor/arch/012-leader-receiver-creator.md
A dummy implementation can be found here: https://github.com/skhalash/leaderreceivercreator

Criterias

• Have the new receiver buildable
• The receiver can be configured with the typical lease configuration (see https://github.com/kyma-project/telemetry-manager/blob/main/docs/contributor/arch/012-leader-receiver-creator.md)
• The receiver can be configured with a nested receiver configuration
• If the instance is able to acquire the lease, the nested receiver will be enabled
• If the instance is cannot renew the lease, the nested receiver will be destroyed and is not active
• Have a readme comparable to the upstream readme's, summarizing the API and usage pattern
• Understand what metrics are available already and define what should be added in a follow-up

Reasons

Attachments

[rakesh-garimella]

Following has been implemented:

• new receiver is buildable.
• leader election receiver takes the input from the defined config file
• When the leader election is won the sub-receiver starts and when it looses the sub-receiver stops
• The sub-receiver that has been added is k8s cluster receiver
• Readme has been updated
• unit tests have been added
• Sub receiver metrics are present out of box eg:

otelcol_receiver_accepted_metric_points{receiver="k8s_cluster//singleton_receiver_creator",service_instance_id="d35b0935-4f95-4f7e-8074-89dee76a698a",service_name="kyma-otelcol",service_version="0.102.1",transport="http"} 1218
# HELP otelcol_receiver_refused_metric_points Number of metric points that could not be pushed into the pipeline.
# TYPE otelcol_receiver_refused_metric_points counter
otelcol_receiver_refused_metric_points{receiver="k8s_cluster//singleton_receiver_creator",service_instance_id="d35b0935-4f95-4f7e-8074-89dee76a698a",service_name="kyma-otelcol",service_version="0.102.1",transport="http"} 0

What is missing is metrics from singleton receiver. We can have following custom metrics:

• lease_holder