Add Max Allocated Storage metric for RDS

[asaf400]

An attempt to add the 'Max Allocated Storage' data field as a metric..

Could be useful for storage related alerts, to be able to 'know' the max limit of the RDS instance\cluster config

Edit: I tried running make and or make test but it failed with:

[user@LAPTOP-ASAF-T14 aws-resource-exporter]# make
go vet ./...
go test -race -short github.com/app-sre/aws-resource-exporter github.com/app-sre/aws-resource-exporter/pkg github.com/app-sre/aws-resource-exporter/pkg/awsclient github.com/app-sre/aws-resource-exporter/pkg/awsclient/mock -count=1
?       github.com/app-sre/aws-resource-exporter        [no test files]
--- FAIL: TestAddAllInstanceMetrics (0.00s)
    rds_test.go:91: 
                Error Trace:    /root/gits/aws-resource-exporter/pkg/rds_test.go:91
                Error:          "[%!s(*prometheus.constMetric=&{0xc00044bb90 2 1 [0xc0000ab3e0 0xc0000ab410 0xc0000ab440]}) %!s(*prometheus.constMetric=&{0xc00044bb20 2 1 [0xc0000ab620 0xc0000ab650 0xc0000ab680]}) %!s(*prometheus.constMetric=&{0xc00044bea0 2 0 [0xc0000aaff0 0xc0000ab020]}) %!s(*prometheus.constMetric=&{0xc00044bc70 1 0 [0xc0000ab0b0 0xc0000ab0e0]}) %!s(*prometheus.constMetric=&{0xc00044bce0 2 1646 [0xc0000ab170 0xc0000ab1a0]}) %!s(*prometheus.constMetric=&{0xc00044bab0 2 1.099511627776e+12 [0xc0000ab2f0 0xc0000ab320]}) %!s(*prometheus.constMetric=&{0xc00044bc00 2 1 [0xc0000ab4d0 0xc0000ab500 0xc0000ab530 0xc0000ab560]}) %!s(*prometheus.constMetric=&{0xc00044bd50 2 0 [0xc0000aae40 0xc0000aae70 0xc0000aaea0]}) %!s(*prometheus.constMetric=&{0xc00044be30 2 0 [0xc0000aaf30 0xc0000aaf60]}) %!s(*prometheus.constMetric=&{0xc00044ba40 2 1.099511627776e+12 [0xc0000ab230 0xc0000ab260]})]" should have 9 item(s), but has 10
                Test:           TestAddAllInstanceMetrics
FAIL
FAIL    github.com/app-sre/aws-resource-exporter/pkg    4.024s
?       github.com/app-sre/aws-resource-exporter/pkg/awsclient  [no test files]
?       github.com/app-sre/aws-resource-exporter/pkg/awsclient/mock     [no test files]
FAIL
make: *** [Makefile:69: test-unit] Error 1

[app-sre-bot]

Can one of the admins verify this patch?

[asaf400]

Nevermind, I now change the assertion for the length of metrics returned, and test passed

[asaf400]

I confirmed it works on aws account:

# HELP aws_resources_exporter_rds_maxallocatedstorage The amount of max allocated storage for RDS storage autoscaling in bytes.
# TYPE aws_resources_exporter_rds_maxallocatedstorage gauge
aws_resources_exporter_rds_maxallocatedstorage{aws_region="us-east-1",dbinstance_identifier="infra-db"} 1.073741824e+11

100gb max allocated storage, as configured in RDS

[janboll]

test this please

[janboll]

Can you please rebase your branch with the main one?

[asaf400]

Sure thing, I rebased.
I will also:

• Create tests (1 with maxStorage value, 1 without [nil] )
• Update the Readme markdown table