Add support for tracking RDS pending maintenance actions

[steveteahan]

Having information about RDS pending maintenance actions can be helpful in addition to the engine_version data for tracking database maintenance initiatives.

A database that doesn't require maintenance will look like this:

aws_resources_exporter_rds_pendingmaintenanceactions{action="",auto_apply_after="",aws_region="us-east-1",current_apply_date="",dbinstance_identifier="<some_identifier>",description=""} 0

And a database that requires maintenance will have a metric like:

aws_resources_exporter_rds_pendingmaintenanceactions{action="system-update",auto_apply_after="2022-06-30 00:00:00 +0000 UTC",aws_region="us-east-1",current_apply_date="2022-06-30 00:00:00 +0000 UTC",dbinstance_identifier="<some_identifier>",description="New Operating System update is available"} 1

Testing

I executed this locally against an AWS account with >50 RDS instances:

• Confirmed that a metric was published for each RDS instance
• Confirmed that the metric was correctly identifying those instances needing maintenance or not

[BumbleFeng]

aws-resource-exporter are CrashLoopBackOff with error

level=info ts=2022-06-02T08:36:58.626Z caller=main.go:45 msg=Startingaws_resources_exporter version="(version=, branch=, revision=)"
level=info ts=2022-06-02T08:36:58.626Z caller=main.go:46 msg="Build context" (gogo1.16.13,user,date)=(MISSING)
level=info ts=2022-06-02T08:36:58.626Z caller=rds.go:205 msg="Initializing RDS exporter"
level=info ts=2022-06-02T08:36:58.626Z caller=main.go:86 msg="Starting HTTP server" address=:9115
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x98ca5d]
goroutine 25 [running]:
main.(*RDSExporter).Collect(0xc00028da40, 0xc0000922a0)
/var/lib/jenkins/workspace/app-sre-aws-resource-exporter-gh-build-master/rds.go:396 +0x261d
github.com/prometheus/client_golang/prometheus.(*Registry).Gather.func1()
/var/lib/jenkins/go/pkg/mod/github.com/prometheus/[email protected]/prometheus/registry.go:443 +0x12b
created by github.com/prometheus/client_golang/prometheus.(*Registry).Gather
/var/lib/jenkins/go/pkg/mod/github.com/prometheus/[email protected]/prometheus/registry.go:535 +0xe4d

[steveteahan]

This was fixed in #33