v0.11.3 - Bunch of new features, and a couple of bug fixes.

[manugarg]

Metrics export enhancements

• Two shiny new surfacers: AWS CloudWatch and Datadog. (Add datadog surfacer #141 & Add a cloudwatch surfacer #583).
• You can now configure any surfacer to export metrics as gauge. You just need to add export_as_gauge to the surfacer config. (Add a way to export gauge metrics and other changes. #604)
• Also, now you can add failure metric to any surfacer by adding add_failure_metric to the surfacer config. (Add a way to export gauge metrics and other changes. #604)
• A common way to filter metrics. You now have fine-grained control of which metrics will be exported to which surfacer, e.g. you may want to send only critical probe metrics to an expensive monitoring system, while you may send all metrics to pub/sub or files. (Provide a common way to filter metrics. #597)

Labeling

• Multiple substitutions: We now support multiple substitutions in labels, e.g. a label like @target.name@:@target.port@@target.relative_url@ will get appropriately substituted. (Allow multiple substitution tokens in additional labels #582)

Targets Discovery

• RDS provider for file based targets. To allow sharing a large set of targets across multiple probes.
• Implement caching in RDS protocol. No need to re-process (on RDS server or client) targets that haven't changed. (Implement caching in RDS protocol.  #646)
  [Above two changes allowed cloudprober to work with 1M targets in a single targets file. (Reduce resource consumption when using file discovery with same file in multiple probes #634)]
• Add "node" and "pod" labels for K8s endpoints resources. (RDS Kubernetes Endpoints include pod name #612)

Bug Fixes

• External probe: Generate metrics even if requests timeout. (Metrics not updated on external probe timeout #653)
• External probe: Add additional labels to payload based metrics as well. (additional_label's are missing in custom metrics of EXTERNAL probe #654)
• HTTP Probe: Fix parallelism when running multiple requests per probe. (Increase MaxIdleConnsPerHost based on requests-per-probe parameter. #647)

Complete list of commits since the last release: v0.11.2...v0.11.3
Bugs/PR in this release: Milestone v0.11.3.