http: Check HTTPUseCache in a single place

HTTPUseCache is only used is a gate for allowing QueryOptions.UseCache to be enabled. By
moving it to the place where the query options are set, this behaviour is more obvious.

Also remove parseInternal which was an alias for parse.

agent/catalog_endpoint.go

@@ -5,8 +5,9 @@ import (
 	"net/http"
 	"strings"
 
-	"github.com/armon/go-metrics"
+	metrics "github.com/armon/go-metrics"
 	"github.com/armon/go-metrics/prometheus"
+
 	cachetype "github.com/hashicorp/consul/agent/cache-types"
 	"github.com/hashicorp/consul/agent/structs"
 )
@@ -200,7 +201,7 @@ func (s *HTTPHandlers) CatalogDatacenters(resp http.ResponseWriter, req *http.Re
 	parseCacheControl(resp, req, &args.QueryOptions)
 	var out []string
 
-	if s.agent.config.HTTPUseCache && args.QueryOptions.UseCache {
+	if args.QueryOptions.UseCache {
 		raw, m, err := s.agent.cache.Get(req.Context(), cachetype.CatalogDatacentersName, &args)
 		if err != nil {
 			metrics.IncrCounterWithLabels([]string{"client", "rpc", "error", "catalog_datacenters"}, 1,
@@ -282,7 +283,7 @@ func (s *HTTPHandlers) CatalogServices(resp http.ResponseWriter, req *http.Reque
 	var out structs.IndexedServices
 	defer setMeta(resp, &out.QueryMeta)
 
-	if s.agent.config.HTTPUseCache && args.QueryOptions.UseCache {
+	if args.QueryOptions.UseCache {
 		raw, m, err := s.agent.cache.Get(req.Context(), cachetype.CatalogListServicesName, &args)
 		if err != nil {
 			metrics.IncrCounterWithLabels([]string{"client", "rpc", "error", "catalog_services"}, 1,
@@ -371,7 +372,7 @@ func (s *HTTPHandlers) catalogServiceNodes(resp http.ResponseWriter, req *http.R
 	var out structs.IndexedServiceNodes
 	defer setMeta(resp, &out.QueryMeta)
 
-	if s.agent.config.HTTPUseCache && args.QueryOptions.UseCache {
+	if args.QueryOptions.UseCache {
 		raw, m, err := s.agent.cache.Get(req.Context(), cachetype.CatalogServicesName, &args)
 		if err != nil {
 			metrics.IncrCounterWithLabels([]string{"client", "rpc", "error", "catalog_service_nodes"}, 1,

agent/discovery_chain_endpoint.go

@@ -6,10 +6,11 @@ import (
 	"strings"
 	"time"
 
+	"github.com/mitchellh/mapstructure"
+
 	cachetype "github.com/hashicorp/consul/agent/cache-types"
 	"github.com/hashicorp/consul/agent/structs"
 	"github.com/hashicorp/consul/lib/decode"
-	"github.com/mitchellh/mapstructure"
 )
 
 func (s *HTTPHandlers) DiscoveryChainRead(resp http.ResponseWriter, req *http.Request) (interface{}, error) {
@@ -59,7 +60,7 @@ func (s *HTTPHandlers) DiscoveryChainRead(resp http.ResponseWriter, req *http.Re
 	var out structs.DiscoveryChainResponse
 	defer setMeta(resp, &out.QueryMeta)
 
-	if s.agent.config.HTTPUseCache && args.QueryOptions.UseCache {
+	if args.QueryOptions.UseCache {
 		raw, m, err := s.agent.cache.Get(req.Context(), cachetype.CompiledDiscoveryChainName, &args)
 		if err != nil {
 			return nil, err

agent/http.go

@@ -18,6 +18,10 @@ import (
 	"github.com/NYTimes/gziphandler"
 	"github.com/armon/go-metrics"
 	"github.com/armon/go-metrics/prometheus"
+	"github.com/hashicorp/go-cleanhttp"
+	"github.com/mitchellh/mapstructure"
+	"github.com/pkg/errors"
+
 	"github.com/hashicorp/consul/acl"
 	"github.com/hashicorp/consul/agent/cache"
 	"github.com/hashicorp/consul/agent/config"
@@ -27,9 +31,6 @@ import (
 	"github.com/hashicorp/consul/api"
 	"github.com/hashicorp/consul/lib"
 	"github.com/hashicorp/consul/logging"
-	"github.com/hashicorp/go-cleanhttp"
-	"github.com/mitchellh/mapstructure"
-	"github.com/pkg/errors"
 )
 
 var HTTPSummaries = []prometheus.SummaryDefinition{
@@ -858,7 +859,7 @@ func (s *HTTPHandlers) parseConsistency(resp http.ResponseWriter, req *http.Requ
 	if _, ok := query["leader"]; ok {
 		defaults = false
 	}
-	if _, ok := query["cached"]; ok {
+	if _, ok := query["cached"]; ok && s.agent.config.HTTPUseCache {
 		b.SetUseCache(true)
 		defaults = false
 	}
@@ -1037,9 +1038,9 @@ func parseMetaPair(raw string) (string, string) {
 	return pair[0], ""
 }
 
-// parseInternal is a convenience method for endpoints that need
+// parse is a convenience method for endpoints that need to use both parseWait
-// to use both parseWait and parseDC.
+// and parseDC.
-func (s *HTTPHandlers) parseInternal(resp http.ResponseWriter, req *http.Request, dc *string, b structs.QueryOptionsCompat) bool {
+func (s *HTTPHandlers) parse(resp http.ResponseWriter, req *http.Request, dc *string, b structs.QueryOptionsCompat) bool {
 	s.parseDC(req, dc)
 	var token string
 	s.parseTokenWithDefault(req, &token)
@@ -1056,12 +1057,6 @@ func (s *HTTPHandlers) parseInternal(resp http.ResponseWriter, req *http.Request
 	return parseWait(resp, req, b)
 }
 
-// parse is a convenience method for endpoints that need
-// to use both parseWait and parseDC.
-func (s *HTTPHandlers) parse(resp http.ResponseWriter, req *http.Request, dc *string, b structs.QueryOptionsCompat) bool {
-	return s.parseInternal(resp, req, dc, b)
-}
-
 func (s *HTTPHandlers) checkWriteAccess(req *http.Request) error {
 	if req.Method == http.MethodGet || req.Method == http.MethodHead || req.Method == http.MethodOptions {
 		return nil

agent/prepared_query_endpoint.go

@@ -120,7 +120,7 @@ func (s *HTTPHandlers) preparedQueryExecute(id string, resp http.ResponseWriter,
 	var reply structs.PreparedQueryExecuteResponse
 	defer setMeta(resp, &reply.QueryMeta)
 
-	if s.agent.config.HTTPUseCache && args.QueryOptions.UseCache {
+	if args.QueryOptions.UseCache {
 		raw, m, err := s.agent.cache.Get(req.Context(), cachetype.PreparedQueryName, &args)
 		if err != nil {
 			// Don't return error if StaleIfError is set and we are within it and had