web: use chained WithInstrumentation (#6661)

* web: use chained WithInstrumentation

Requires an update of github.com/prometheus/common
* Update yaml.v2

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>

go.mod

@@ -33,7 +33,7 @@ require (
 	github.com/prometheus/alertmanager v0.18.0
 	github.com/prometheus/client_golang v1.2.0
 	github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4
-	github.com/prometheus/common v0.7.0
+	github.com/prometheus/common v0.8.0
 	github.com/samuel/go-zookeeper v0.0.0-20190810000440-0ceca61e4d75
 	github.com/shurcooL/httpfs v0.0.0-20190707220628-8d4bc4ba7749
 	github.com/shurcooL/vfsgen v0.0.0-20181202132449-6a9ea43bcacd
@@ -49,7 +49,7 @@ require (
 	google.golang.org/grpc v1.22.1
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6
 	gopkg.in/fsnotify/fsnotify.v1 v1.4.7
-	gopkg.in/yaml.v2 v2.2.2
+	gopkg.in/yaml.v2 v2.2.7
 	gopkg.in/yaml.v3 v3.0.0-20191120175047-4206685974f2
 	k8s.io/api v0.0.0-20190813020757-36bff7324fb7
 	k8s.io/apimachinery v0.0.0-20190809020650-423f5d784010

go.sum

@@ -308,6 +308,8 @@ github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:
 github.com/prometheus/common v0.4.1/go.mod h1:TNfzLD0ON7rHzMJeJkieUDPYmFC7Snx/y86RQel1bk4=
 github.com/prometheus/common v0.7.0 h1:L+1lyG48J1zAQXA3RBX/nG/B3gjlHq0zTt2tlbJLyCY=
 github.com/prometheus/common v0.7.0/go.mod h1:DjGbpBbp5NYNiECxcL/VnbXCCaQpKd3tt26CguLLsqA=
+github.com/prometheus/common v0.8.0 h1:bLkjvFe2ZRX1DpcgZcdf7j/+MnusEps5hktST/FHA34=
+github.com/prometheus/common v0.8.0/go.mod h1:PC/OgXc+UN7B4ALwvn1yzVZmVwvhXp5JsbBv6wSv6i0=
 github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d/go.mod h1:c3At6R/oaqEKCNdg8wHV1ftS6bRYblBhIjjI8uT2IGk=
 github.com/prometheus/procfs v0.0.2/go.mod h1:TjEm7ze935MbeOT/UhFTIMYKhuLP4wbCsTZCD3I8kEA=
 github.com/prometheus/procfs v0.0.5 h1:3+auTFlqw+ZaQYJARz6ArODtkaIwtvBTx3N2NehQlL8=
@@ -482,6 +484,10 @@ gopkg.in/yaml.v2 v2.0.0-20170812160011-eb3733d160e7/go.mod h1:JAlM8MvJe8wmxCU4Bl
 gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.4 h1:/eiJrUcujPVeJ3xlSWaiNi3uSVmDGBK1pDHUHAnao1I=
+gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.7 h1:VUgggvou5XRW9mHwD/yXxIYSMtY0zoKQf/v226p2nyo=
+gopkg.in/yaml.v2 v2.2.7/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v3 v3.0.0-20191120175047-4206685974f2 h1:XZx7nhd5GMaZpmDaEHFVafUZC7ya0fuo7cSJ3UCKYmM=
 gopkg.in/yaml.v3 v3.0.0-20191120175047-4206685974f2/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

vendor/github.com/prometheus/common/route/route.go

@@ -53,6 +53,12 @@ func New() *Router {
 
 // WithInstrumentation returns a router with instrumentation support.
 func (r *Router) WithInstrumentation(instrh func(handlerName string, handler http.HandlerFunc) http.HandlerFunc) *Router {
+	if r.instrh != nil {
+		newInstrh := instrh
+		instrh = func(handlerName string, handler http.HandlerFunc) http.HandlerFunc {
+			return newInstrh(handlerName, r.instrh(handlerName, handler))
+		}
+	}
 	return &Router{rtr: r.rtr, prefix: r.prefix, instrh: instrh}
 }
 

vendor/github.com/prometheus/common/version/info.go

@@ -33,9 +33,10 @@ var (
 	GoVersion = runtime.Version()
 )
 
-// NewCollector returns a collector which exports metrics about current version information.
-func NewCollector(program string) *prometheus.GaugeVec {
-	buildInfo := prometheus.NewGaugeVec(
+// NewCollector returns a collector that exports metrics about current version
+// information.
+func NewCollector(program string) prometheus.Collector {
+	return prometheus.NewGaugeFunc(
 		prometheus.GaugeOpts{
 			Namespace: program,
 			Name:      "build_info",
@@ -43,11 +44,15 @@ func NewCollector(program string) *prometheus.GaugeVec {
 				"A metric with a constant '1' value labeled by version, revision, branch, and goversion from which %s was built.",
 				program,
 			),
+			ConstLabels: prometheus.Labels{
+				"version":   Version,
+				"revision":  Revision,
+				"branch":    Branch,
+				"goversion": GoVersion,
+			},
 		},
-		[]string{"version", "revision", "branch", "goversion"},
+		func() float64 { return 1 },
 	)
-	buildInfo.WithLabelValues(Version, Revision, Branch, GoVersion).Set(1)
-	return buildInfo
 }
 
 // versionInfoTmpl contains the template used by Info.

vendor/gopkg.in/yaml.v2/.travis.yml

@@ -1,12 +1,16 @@
 language: go
 
 go:
-    - 1.4
-    - 1.5
-    - 1.6
-    - 1.7
-    - 1.8
-    - 1.9
-    - tip
+    - "1.4.x"
+    - "1.5.x"
+    - "1.6.x"
+    - "1.7.x"
+    - "1.8.x"
+    - "1.9.x"
+    - "1.10.x"
+    - "1.11.x"
+    - "1.12.x"
+    - "1.13.x"
+    - "tip"
 
 go_import_path: gopkg.in/yaml.v2

vendor/gopkg.in/yaml.v2/decode.go

@@ -229,6 +229,10 @@ type decoder struct {
 	mapType reflect.Type
 	terrors []string
 	strict  bool
+
+	decodeCount int
+	aliasCount  int
+	aliasDepth  int
 }
 
 var (
@@ -314,7 +318,43 @@ func (d *decoder) prepare(n *node, out reflect.Value) (newout reflect.Value, unm
 	return out, false, false
 }
 
+const (
+	// 400,000 decode operations is ~500kb of dense object declarations, or
+	// ~5kb of dense object declarations with 10000% alias expansion
+	alias_ratio_range_low = 400000
+
+	// 4,000,000 decode operations is ~5MB of dense object declarations, or
+	// ~4.5MB of dense object declarations with 10% alias expansion
+	alias_ratio_range_high = 4000000
+
+	// alias_ratio_range is the range over which we scale allowed alias ratios
+	alias_ratio_range = float64(alias_ratio_range_high - alias_ratio_range_low)
+)
+
+func allowedAliasRatio(decodeCount int) float64 {
+	switch {
+	case decodeCount <= alias_ratio_range_low:
+		// allow 99% to come from alias expansion for small-to-medium documents
+		return 0.99
+	case decodeCount >= alias_ratio_range_high:
+		// allow 10% to come from alias expansion for very large documents
+		return 0.10
+	default:
+		// scale smoothly from 99% down to 10% over the range.
+		// this maps to 396,000 - 400,000 allowed alias-driven decodes over the range.
+		// 400,000 decode operations is ~100MB of allocations in worst-case scenarios (single-item maps).
+		return 0.99 - 0.89*(float64(decodeCount-alias_ratio_range_low)/alias_ratio_range)
+	}
+}
+
 func (d *decoder) unmarshal(n *node, out reflect.Value) (good bool) {
+	d.decodeCount++
+	if d.aliasDepth > 0 {
+		d.aliasCount++
+	}
+	if d.aliasCount > 100 && d.decodeCount > 1000 && float64(d.aliasCount)/float64(d.decodeCount) > allowedAliasRatio(d.decodeCount) {
+		failf("document contains excessive aliasing")
+	}
 	switch n.kind {
 	case documentNode:
 		return d.document(n, out)
@@ -353,7 +393,9 @@ func (d *decoder) alias(n *node, out reflect.Value) (good bool) {
 		failf("anchor '%s' value contains itself", n.value)
 	}
 	d.aliases[n] = true
+	d.aliasDepth++
 	good = d.unmarshal(n.alias, out)
+	d.aliasDepth--
 	delete(d.aliases, n)
 	return good
 }
@@ -746,8 +788,7 @@ func (d *decoder) merge(n *node, out reflect.Value) {
 	case mappingNode:
 		d.unmarshal(n, out)
 	case aliasNode:
-		an, ok := d.doc.anchors[n.value]
-		if ok && an.kind != mappingNode {
+		if n.alias != nil && n.alias.kind != mappingNode {
 			failWantMap()
 		}
 		d.unmarshal(n, out)
@@ -756,8 +797,7 @@ func (d *decoder) merge(n *node, out reflect.Value) {
 		for i := len(n.children) - 1; i >= 0; i-- {
 			ni := n.children[i]
 			if ni.kind == aliasNode {
-				an, ok := d.doc.anchors[ni.value]
-				if ok && an.kind != mappingNode {
+				if ni.alias != nil && ni.alias.kind != mappingNode {
 					failWantMap()
 				}
 			} else if ni.kind != mappingNode {

vendor/gopkg.in/yaml.v2/resolve.go

@@ -81,7 +81,7 @@ func resolvableTag(tag string) bool {
 	return false
 }
 
-var yamlStyleFloat = regexp.MustCompile(`^[-+]?[0-9]*\.?[0-9]+([eE][-+][0-9]+)?$`)
+var yamlStyleFloat = regexp.MustCompile(`^[-+]?(\.[0-9]+|[0-9]+(\.[0-9]*)?)([eE][-+]?[0-9]+)?$`)
 
 func resolve(tag string, in string) (rtag string, out interface{}) {
 	if !resolvableTag(tag) {

vendor/gopkg.in/yaml.v2/scannerc.go

@@ -634,13 +634,14 @@ func yaml_parser_fetch_more_tokens(parser *yaml_parser_t) bool {
 			need_more_tokens = true
 		} else {
 			// Check if any potential simple key may occupy the head position.
-			if !yaml_parser_stale_simple_keys(parser) {
-				return false
-			}
-
-			for i := range parser.simple_keys {
+			for i := len(parser.simple_keys) - 1; i >= 0; i-- {
 				simple_key := &parser.simple_keys[i]
-				if simple_key.possible && simple_key.token_number == parser.tokens_parsed {
+				if simple_key.token_number < parser.tokens_parsed {
+					break
+				}
+				if valid, ok := yaml_simple_key_is_valid(parser, simple_key); !ok {
+					return false
+				} else if valid && simple_key.token_number == parser.tokens_parsed {
 					need_more_tokens = true
 					break
 				}
@@ -678,11 +679,6 @@ func yaml_parser_fetch_next_token(parser *yaml_parser_t) bool {
 		return false
 	}
 
-	// Remove obsolete potential simple keys.
-	if !yaml_parser_stale_simple_keys(parser) {
-		return false
-	}
-
 	// Check the indentation level against the current column.
 	if !yaml_parser_unroll_indent(parser, parser.mark.column) {
 		return false
@@ -837,29 +833,30 @@ func yaml_parser_fetch_next_token(parser *yaml_parser_t) bool {
 		"found character that cannot start any token")
 }
 
-// Check the list of potential simple keys and remove the positions that
-// cannot contain simple keys anymore.
-func yaml_parser_stale_simple_keys(parser *yaml_parser_t) bool {
-	// Check for a potential simple key for each flow level.
-	for i := range parser.simple_keys {
-		simple_key := &parser.simple_keys[i]
-
-		// The specification requires that a simple key
-		//
-		//  - is limited to a single line,
-		//  - is shorter than 1024 characters.
-		if simple_key.possible && (simple_key.mark.line < parser.mark.line || simple_key.mark.index+1024 < parser.mark.index) {
-
-			// Check if the potential simple key to be removed is required.
-			if simple_key.required {
-				return yaml_parser_set_scanner_error(parser,
-					"while scanning a simple key", simple_key.mark,
-					"could not find expected ':'")
-			}
-			simple_key.possible = false
-		}
+func yaml_simple_key_is_valid(parser *yaml_parser_t, simple_key *yaml_simple_key_t) (valid, ok bool) {
+	if !simple_key.possible {
+		return false, true
 	}
-	return true
+
+	// The 1.2 specification says:
+	//
+	//     "If the ? indicator is omitted, parsing needs to see past the
+	//     implicit key to recognize it as such. To limit the amount of
+	//     lookahead required, the “:” indicator must appear at most 1024
+	//     Unicode characters beyond the start of the key. In addition, the key
+	//     is restricted to a single line."
+	//
+	if simple_key.mark.line < parser.mark.line || simple_key.mark.index+1024 < parser.mark.index {
+		// Check if the potential simple key to be removed is required.
+		if simple_key.required {
+			return false, yaml_parser_set_scanner_error(parser,
+				"while scanning a simple key", simple_key.mark,
+				"could not find expected ':'")
+		}
+		simple_key.possible = false
+		return false, true
+	}
+	return true, true
 }
 
 // Check if a simple key may start at the current position and add it if
@@ -879,8 +876,8 @@ func yaml_parser_save_simple_key(parser *yaml_parser_t) bool {
 			possible:     true,
 			required:     required,
 			token_number: parser.tokens_parsed + (len(parser.tokens) - parser.tokens_head),
+			mark:         parser.mark,
 		}
-		simple_key.mark = parser.mark
 
 		if !yaml_parser_remove_simple_key(parser) {
 			return false
@@ -906,13 +903,26 @@ func yaml_parser_remove_simple_key(parser *yaml_parser_t) bool {
 	return true
 }
 
+// max_flow_level limits the flow_level
+const max_flow_level = 10000
+
 // Increase the flow level and resize the simple key list if needed.
 func yaml_parser_increase_flow_level(parser *yaml_parser_t) bool {
 	// Reset the simple key on the next level.
-	parser.simple_keys = append(parser.simple_keys, yaml_simple_key_t{})
+	parser.simple_keys = append(parser.simple_keys, yaml_simple_key_t{
+		possible:     false,
+		required:     false,
+		token_number: parser.tokens_parsed + (len(parser.tokens) - parser.tokens_head),
+		mark:         parser.mark,
+	})
 
 	// Increase the flow level.
 	parser.flow_level++
+	if parser.flow_level > max_flow_level {
+		return yaml_parser_set_scanner_error(parser,
+			"while increasing flow level", parser.simple_keys[len(parser.simple_keys)-1].mark,
+			fmt.Sprintf("exceeded max depth of %d", max_flow_level))
+	}
 	return true
 }
 
@@ -925,6 +935,9 @@ func yaml_parser_decrease_flow_level(parser *yaml_parser_t) bool {
 	return true
 }
 
+// max_indents limits the indents stack size
+const max_indents = 10000
+
 // Push the current indentation level to the stack and set the new level
 // the current column is greater than the indentation level.  In this case,
 // append or insert the specified token into the token queue.
@@ -939,6 +952,11 @@ func yaml_parser_roll_indent(parser *yaml_parser_t, column, number int, typ yaml
 		// indentation level.
 		parser.indents = append(parser.indents, parser.indent)
 		parser.indent = column
+		if len(parser.indents) > max_indents {
+			return yaml_parser_set_scanner_error(parser,
+				"while increasing indent level", parser.simple_keys[len(parser.simple_keys)-1].mark,
+				fmt.Sprintf("exceeded max depth of %d", max_indents))
+		}
 
 		// Create a token and insert it into the queue.
 		token := yaml_token_t{
@@ -1270,7 +1288,11 @@ func yaml_parser_fetch_value(parser *yaml_parser_t) bool {
 	simple_key := &parser.simple_keys[len(parser.simple_keys)-1]
 
 	// Have we found a simple key?
-	if simple_key.possible {
+	if valid, ok := yaml_simple_key_is_valid(parser, simple_key); !ok {
+		return false
+
+	} else if valid {
+
 		// Create the KEY token and insert it into the queue.
 		token := yaml_token_t{
 			typ:        yaml_KEY_TOKEN,

vendor/gopkg.in/yaml.v2/yaml.go

@@ -89,7 +89,7 @@ func UnmarshalStrict(in []byte, out interface{}) (err error) {
 	return unmarshal(in, out, true)
 }
 
-// A Decorder reads and decodes YAML values from an input stream.
+// A Decoder reads and decodes YAML values from an input stream.
 type Decoder struct {
 	strict bool
 	parser *parser

vendor/modules.txt

@@ -274,7 +274,7 @@ github.com/prometheus/client_golang/prometheus/promhttp
 github.com/prometheus/client_golang/prometheus/testutil
 # github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4
 github.com/prometheus/client_model/go
-# github.com/prometheus/common v0.7.0
+# github.com/prometheus/common v0.8.0
 github.com/prometheus/common/config
 github.com/prometheus/common/expfmt
 github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg
@@ -442,7 +442,7 @@ gopkg.in/alecthomas/kingpin.v2
 gopkg.in/fsnotify/fsnotify.v1
 # gopkg.in/inf.v0 v0.9.0
 gopkg.in/inf.v0
-# gopkg.in/yaml.v2 v2.2.2
+# gopkg.in/yaml.v2 v2.2.7
 gopkg.in/yaml.v2
 # gopkg.in/yaml.v3 v3.0.0-20191120175047-4206685974f2
 gopkg.in/yaml.v3

web/web.go

@@ -254,10 +254,8 @@ func New(logger log.Logger, o *Options) *Handler {
 
 	m := newMetrics(o.Registerer)
 	router := route.New().
-		WithInstrumentation(combineInstrumentations(
-			m.instrumentHandler,
-			setPathWithPrefix(""),
-		))
+		WithInstrumentation(m.instrumentHandler).
+		WithInstrumentation(setPathWithPrefix(""))
 
 	cwd, err := os.Getwd()
 	if err != nil {
@@ -552,10 +550,8 @@ func (h *Handler) Run(ctx context.Context) error {
 		level.Info(h.logger).Log("msg", "router prefix", "prefix", h.options.RoutePrefix)
 	}
 	av1 := route.New().
-		WithInstrumentation(combineInstrumentations(
-			h.metrics.instrumentHandlerWithPrefix("/api/v1"),
-			setPathWithPrefix(apiPath+"/v1"),
-		))
+		WithInstrumentation(h.metrics.instrumentHandlerWithPrefix("/api/v1")).
+		WithInstrumentation(setPathWithPrefix(apiPath + "/v1"))
 	h.apiV1.Register(av1)
 
 	mux.Handle(apiPath+"/v1/", http.StripPrefix(apiPath+"/v1", av1))
@@ -1118,15 +1114,6 @@ type AlertByStateCount struct {
 	Firing   int32
 }
 
-func combineInstrumentations(fs ...func(handlerName string, handler http.HandlerFunc) http.HandlerFunc) func(string, http.HandlerFunc) http.HandlerFunc {
-	return func(handlerName string, handler http.HandlerFunc) http.HandlerFunc {
-		for _, f := range fs {
-			handler = f(handlerName, handler)
-		}
-		return handler
-	}
-}
-
 func setPathWithPrefix(prefix string) func(handlerName string, handler http.HandlerFunc) http.HandlerFunc {
 	return func(handlerName string, handler http.HandlerFunc) http.HandlerFunc {
 		return func(w http.ResponseWriter, r *http.Request) {