Reduce memory utilization in downstream projects creating multiple Al…

…ertmanager instances (#3114) * Reduce memory utilization in downstream projects creating multiple Alertmanager instances Signed-off-by: Marco Pracucci <marco@pracucci.com>
prometheus · Oct 26, 2022 · 33bba95 · 33bba95
1 parent 28c3df0
commit 33bba95
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Showing 3 changed files with 17 additions and 12 deletions.
diff --git a/api/v2/api.go b/api/v2/api.go
@@ -23,6 +23,7 @@ import (
 
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
+	"github.com/go-openapi/analysis"
 	"github.com/go-openapi/loads"
 	"github.com/go-openapi/runtime/middleware"
 	"github.com/go-openapi/strfmt"
@@ -101,7 +102,7 @@ func NewAPI(
 	}
 
 	// Load embedded swagger file.
-	swaggerSpec, err := getSwaggerSpec()
+	swaggerSpec, swaggerSpecAnalysis, err := getSwaggerSpec()
 	if err != nil {
 		return nil, err
 	}
@@ -113,7 +114,9 @@ func NewAPI(
 	// the API itself via RoutesHandler. See:
 	// https://github.com/go-swagger/go-swagger/issues/1779
 	openAPI.Middleware = func(b middleware.Builder) http.Handler {
-		return middleware.Spec("", swaggerSpec.Raw(), openAPI.Context().RoutesHandler(b))
+		// Manually create the context so that we can use the singleton swaggerSpecAnalysis.
+		swaggerContext := middleware.NewRoutableContextWithAnalyzedSpec(swaggerSpec, swaggerSpecAnalysis, openAPI, nil)
+		return middleware.Spec("", swaggerSpec.Raw(), swaggerContext.RoutesHandler(b))
 	}
 
 	openAPI.AlertGetAlertsHandler = alert_ops.GetAlertsHandlerFunc(api.getAlertsHandler)
@@ -674,29 +677,31 @@ func parseFilter(filter []string) ([]*labels.Matcher, error) {
 }
 
 var (
-	swaggerSpecCacheMx sync.Mutex
-	swaggerSpecCache   *loads.Document
+	swaggerSpecCacheMx       sync.Mutex
+	swaggerSpecCache         *loads.Document
+	swaggerSpecAnalysisCache *analysis.Spec
 )
 
 // getSwaggerSpec loads and caches the swagger spec. If a cached version already exists,
 // it returns the cached one. The reason why we cache it is because some downstream projects
 // (e.g. Grafana Mimir) creates many Alertmanager instances in the same process, so they would
 // incur in a significant memory penalty if we would reload the swagger spec each time.
-func getSwaggerSpec() (*loads.Document, error) {
+func getSwaggerSpec() (*loads.Document, *analysis.Spec, error) {
 	swaggerSpecCacheMx.Lock()
 	defer swaggerSpecCacheMx.Unlock()
 
 	// Check if a cached version exists.
 	if swaggerSpecCache != nil {
-		return swaggerSpecCache, nil
+		return swaggerSpecCache, swaggerSpecAnalysisCache, nil
 	}
 
 	// Load embedded swagger file.
 	swaggerSpec, err := loads.Analyzed(restapi.SwaggerJSON, "")
 	if err != nil {
-		return nil, fmt.Errorf("failed to load embedded swagger file: %w", err)
+		return nil, nil, fmt.Errorf("failed to load embedded swagger file: %w", err)
 	}
 
 	swaggerSpecCache = swaggerSpec
-	return swaggerSpec, nil
+	swaggerSpecAnalysisCache = analysis.New(swaggerSpec.Spec())
+	return swaggerSpec, swaggerSpecAnalysisCache, nil
 }
diff --git a/go.mod b/go.mod
@@ -9,9 +9,10 @@ require (
 	github.com/cenkalti/backoff/v4 v4.1.3
 	github.com/cespare/xxhash/v2 v2.1.2
 	github.com/go-kit/log v0.2.1
+	github.com/go-openapi/analysis v0.21.4
 	github.com/go-openapi/errors v0.20.3
 	github.com/go-openapi/loads v0.21.2
-	github.com/go-openapi/runtime v0.24.1
+	github.com/go-openapi/runtime v0.24.3-0.20221021160911-4425b20330b2
 	github.com/go-openapi/spec v0.20.7
 	github.com/go-openapi/strfmt v0.21.3
 	github.com/go-openapi/swag v0.22.3
@@ -54,7 +55,6 @@ require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/docker/go-units v0.4.0 // indirect
 	github.com/go-logfmt/logfmt v0.5.1 // indirect
-	github.com/go-openapi/analysis v0.21.4 // indirect
 	github.com/go-openapi/jsonpointer v0.19.5 // indirect
 	github.com/go-openapi/jsonreference v0.20.0 // indirect
 	github.com/golang/protobuf v1.5.2 // indirect

diff --git a/go.sum b/go.sum
@@ -114,8 +114,8 @@ github.com/go-openapi/jsonreference v0.20.0/go.mod h1:Ag74Ico3lPc+zR+qjn4XBUmXym
 github.com/go-openapi/loads v0.21.1/go.mod h1:/DtAMXXneXFjbQMGEtbamCZb+4x7eGwkvZCvBmwUG+g=
 github.com/go-openapi/loads v0.21.2 h1:r2a/xFIYeZ4Qd2TnGpWDIQNcP80dIaZgf704za8enro=
 github.com/go-openapi/loads v0.21.2/go.mod h1:Jq58Os6SSGz0rzh62ptiu8Z31I+OTHqmULx5e/gJbNw=
-github.com/go-openapi/runtime v0.24.1 h1:Sml5cgQKGYQHF+M7yYSHaH1eOjvTykrddTE/KtQVjqo=
-github.com/go-openapi/runtime v0.24.1/go.mod h1:AKurw9fNre+h3ELZfk6ILsfvPN+bvvlaU/M9q/r9hpk=
+github.com/go-openapi/runtime v0.24.3-0.20221021160911-4425b20330b2 h1:Vr08+BrsrnvcgikSlS273dkijppZ/M+fL/TMfc/LEJM=
+github.com/go-openapi/runtime v0.24.3-0.20221021160911-4425b20330b2/go.mod h1:AKurw9fNre+h3ELZfk6ILsfvPN+bvvlaU/M9q/r9hpk=
 github.com/go-openapi/spec v0.20.4/go.mod h1:faYFR1CvsJZ0mNsmsphTMSoRrNV3TEDoAM7FOEWeq8I=
 github.com/go-openapi/spec v0.20.6/go.mod h1:2OpW+JddWPrpXSCIX8eOx7lZ5iyuWj3RYR6VaaBKcWA=
 github.com/go-openapi/spec v0.20.7 h1:1Rlu/ZrOCCob0n+JKKJAWhNWMPW8bOZRg8FJaY+0SKI=