Add a rate limit for Prometheus API requests

cmd/pint/tests/0025_config.txt

@@ -16,6 +16,7 @@ level=info msg="Loading configuration file" path=.pint.hcl
       "uri": "https://",
       "timeout": "2m",
       "concurrency": 16,
+      "rateLimit": 100,
       "cache": 10000,
       "required": true
     },
@@ -24,6 +25,7 @@ level=info msg="Loading configuration file" path=.pint.hcl
       "uri": "https://",
       "timeout": "2m",
       "concurrency": 32,
+      "rateLimit": 100,
       "cache": 10000,
       "required": false
     },
@@ -32,8 +34,18 @@ level=info msg="Loading configuration file" path=.pint.hcl
       "uri": "https://",
       "timeout": "10s",
       "concurrency": 16,
+      "rateLimit": 100,
       "cache": 32,
       "required": false
+    },
+    {
+      "name": "custom-rateLimit",
+      "uri": "https://",
+      "timeout": "15s",
+      "concurrency": 16,
+      "rateLimit": 1,
+      "cache": 10000,
+      "required": false
     }
   ],
   "checks": {
@@ -163,6 +175,12 @@ prometheus "custom-cache" {
   cache    = 32
 }
 
+prometheus "custom-rateLimit" {
+  uri       = "https://"
+  timeout   = "15s"
+  rateLimit = 1
+}
+
 checks {
   disabled = ["promql/fragile"]
 }

docs/changelog.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## v0.24.0
+
+### Added
+
+- Added rate limit for Prometheus API requests with a default value of 100
+  requests per second. To customize it set `rateLimit` field inside selected
+  `prometheus` server definition.
+
 ## v0.23.0
 
 ### Fixed

docs/configuration.md

@@ -158,6 +158,7 @@ prometheus "$name" {
   failover    = ["https://...", ...]
   timeout     = "60s"
   concurrency = 16
+  rateLimit   = 100
   cache       = 10000
   required    = true|false
   paths       = ["...", ...]
@@ -176,8 +177,11 @@ prometheus "$name" {
   configuration, otherwise pint checks might return unreliable results and potential
   false positives.
 - `timeout` - timeout to be used for API requests.
-- `concurrency` - how many concurrent requests can pint send to this Prometheus.
+- `concurrency` - how many concurrent requests can pint send to this Prometheus server.
   Optional, defaults to 16.
+- `rateLimit` - per second rate limit for all API requests send to this Prometheus server.
+  Setting it to `1000` would allow for up to 1000 requests per each wall clock second.
+  Optional, default to 100 requests per second.
 - `cache` - size of the query cache, defaults to 10000.
 - `required` - decides how pint will report errors if it's unable to get a valid response
   from this Prometheus server. If `required` is `true` and all API calls to this Prometheus

go.mod

@@ -17,13 +17,15 @@ require (
 	github.com/rs/zerolog v1.27.0
 	github.com/stretchr/testify v1.8.0
 	github.com/urfave/cli/v2 v2.10.3
+	go.uber.org/ratelimit v0.2.0
 	golang.org/x/oauth2 v0.0.0-20220608161450-d0670ef3b1eb
 	gopkg.in/yaml.v3 v3.0.1
 )
 
 require (
 	github.com/agext/levenshtein v1.2.3 // indirect
 	github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137 // indirect
+	github.com/andres-erbsen/clock v0.0.0-20160526145045-9e14626cd129 // indirect
 	github.com/apparentlymart/go-textseg/v13 v13.0.0 // indirect
 	github.com/aws/aws-sdk-go v1.44.35 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect

go.sum

@@ -74,6 +74,8 @@ github.com/alecthomas/units v0.0.0-20190717042225-c3de453c63f4/go.mod h1:ybxpYRF
 github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d/go.mod h1:rBZYJk541a8SKzHPHnH3zbiI+7dagKZ0cgpgrD7Fyho=
 github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137 h1:s6gZFSlWYmbqAuRjVTiNNhvNRfY2Wxp9nhfyel4rklc=
 github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137/go.mod h1:OMCwj8VM1Kc9e19TLln2VL61YJF0x1XFtfdL4JdbSyE=
+github.com/andres-erbsen/clock v0.0.0-20160526145045-9e14626cd129 h1:MzBOUgng9orim59UnfUTLRjMpd09C5uEVQ6RPGeCaVI=
+github.com/andres-erbsen/clock v0.0.0-20160526145045-9e14626cd129/go.mod h1:rFgpPQZYZ8vdbc+48xibu8ALc3yeyd64IhHS+PU6Yyg=
 github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kdvxnR2qWY=
 github.com/apparentlymart/go-textseg/v13 v13.0.0 h1:Y+KvPE1NYz0xl601PVImeQfFyEy6iT90AvPUL1NNfNw=
 github.com/apparentlymart/go-textseg/v13 v13.0.0/go.mod h1:ZK2fH7c4NqDTLtiYLvIkEghdlcqw7yxLeM89kiTRPUo=
@@ -427,10 +429,13 @@ go.opentelemetry.io/otel v1.7.0/go.mod h1:5BdUoMIz5WEs0vt0CUEMtSSaTSHBBVwrhnz7+n
 go.opentelemetry.io/otel/trace v1.7.0 h1:O37Iogk1lEkMRXewVtZ1BBTVn5JEp8GrJvP92bJqC6o=
 go.opentelemetry.io/otel/trace v1.7.0/go.mod h1:fzLSB9nqR2eXzxPXb2JW9IKE+ScyXA48yyE4TNvoHqU=
 go.opentelemetry.io/proto/otlp v0.7.0/go.mod h1:PqfVotwruBrMGOCsRd/89rSnXhoiJIqeYNgFYFoEGnI=
+go.uber.org/atomic v1.7.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
 go.uber.org/atomic v1.9.0 h1:ECmE8Bn/WFTYwEW/bpKD3M8VtR/zQVbavAoalC1PYyE=
 go.uber.org/atomic v1.9.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
 go.uber.org/goleak v1.1.12 h1:gZAh5/EyT/HQwlpkCy6wTpqfH9H8Lz8zbm3dZh+OyzA=
 go.uber.org/goleak v1.1.12/go.mod h1:cwTWslyiVhfpKIDGSZEM2HlOvcqm+tG4zioyIeLoqMQ=
+go.uber.org/ratelimit v0.2.0 h1:UQE2Bgi7p2B85uP5dC2bbRtig0C+OeNRnNEafLjsLPA=
+go.uber.org/ratelimit v0.2.0/go.mod h1:YYBV4e4naJvhpitQrWJu1vCpgB7CboMe0qhltKt6mUg=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=

internal/checks/base_test.go

@@ -62,7 +62,7 @@ func simpleProm(name, uri string, timeout time.Duration, required bool) *promapi
 	return promapi.NewFailoverGroup(
 		name,
 		[]*promapi.Prometheus{
-			promapi.NewPrometheus(name, uri, timeout, 16, 1000),
+			promapi.NewPrometheus(name, uri, timeout, 16, 1000, 1000),
 		},
 		required,
 	)