Revert "agent: add allowStale option for HTTP API (#3142)"

This reverts commit 1e0fd27a74f5b18775ce91a84310430de35a4a80.

agent/config.go

@@ -131,12 +131,6 @@ type DNSConfig struct {
 
 // HTTPConfig is used to fine tune the Http sub-system.
 type HTTPConfig struct {
-	// AllowStale is used to enable lookups with stale
-	// data. This gives horizontal read scalability since
-	// any Consul server can service the query instead of
-	// only the leader.
-	AllowStale *bool `mapstructure:"allow_stale"`
-
 	// ResponseHeaders are used to add HTTP header response fields to the HTTP API responses.
 	ResponseHeaders map[string]string `mapstructure:"response_headers"`
 }
@@ -924,9 +918,6 @@ func DefaultConfig() *Config {
 			MaxStale:        10 * 365 * 24 * time.Hour,
 			RecursorTimeout: 2 * time.Second,
 		},
-		HTTPConfig: HTTPConfig{
-			AllowStale: Bool(true),
-		},
 		Telemetry: Telemetry{
 			StatsitePrefix: "consul",
 		},
@@ -2013,9 +2004,6 @@ func MergeConfig(a, b *Config) *Config {
 			result.HTTPConfig.ResponseHeaders[field] = value
 		}
 	}
-	if b.HTTPConfig.AllowStale != nil {
-		result.HTTPConfig.AllowStale = b.HTTPConfig.AllowStale
-	}
 	if len(b.Meta) != 0 {
 		if result.Meta == nil {
 			result.Meta = make(map[string]string)

agent/http.go

@@ -358,17 +358,15 @@ func parseWait(resp http.ResponseWriter, req *http.Request, b *structs.QueryOpti
 }
 
 // parseConsistency is used to parse the ?stale and ?consistent query params.
-// allowStale forces stale consistency instead of default one if none was provided in the query.
 // Returns true on error
-func parseConsistency(resp http.ResponseWriter, req *http.Request, allowStale bool, b *structs.QueryOptions) bool {
+func parseConsistency(resp http.ResponseWriter, req *http.Request, b *structs.QueryOptions) bool {
 	query := req.URL.Query()
-	if _, ok := query["consistent"]; ok {
-		b.RequireConsistent = true
-	}
-	b.AllowStale = !b.RequireConsistent && allowStale
 	if _, ok := query["stale"]; ok {
 		b.AllowStale = true
 	}
+	if _, ok := query["consistent"]; ok {
+		b.RequireConsistent = true
+	}
 	if b.AllowStale && b.RequireConsistent {
 		resp.WriteHeader(http.StatusBadRequest) // 400
 		fmt.Fprint(resp, "Cannot specify ?stale with ?consistent, conflicting semantics.")
@@ -435,8 +433,7 @@ func (s *HTTPServer) parseMetaFilter(req *http.Request) map[string]string {
 func (s *HTTPServer) parse(resp http.ResponseWriter, req *http.Request, dc *string, b *structs.QueryOptions) bool {
 	s.parseDC(req, dc)
 	s.parseToken(req, &b.Token)
-	allowStale := s.agent.config.HTTPConfig.AllowStale
-	if parseConsistency(resp, req, *allowStale, b) {
+	if parseConsistency(resp, req, b) {
 		return true
 	}
 	return parseWait(resp, req, b)

agent/http_test.go

@@ -436,36 +436,31 @@ func TestParseWait_InvalidIndex(t *testing.T) {
 func TestParseConsistency(t *testing.T) {
 	t.Parallel()
 	resp := httptest.NewRecorder()
+	var b structs.QueryOptions
 
-	tests := []struct {
-		url                   string
-		allowStale            bool
-		wantAllowStale        bool
-		wantRequireConsistent bool
-	}{
-		{"/v1/catalog/nodes?stale", false, true, false},
-		{"/v1/catalog/nodes?stale", true, true, false},
-		{"/v1/catalog/nodes?consistent", false, false, true},
-		{"/v1/catalog/nodes?consistent", true, false, true},
-		{"/v1/catalog/nodes", false, false, false},
-		{"/v1/catalog/nodes", true, true, false},
+	req, _ := http.NewRequest("GET", "/v1/catalog/nodes?stale", nil)
+	if d := parseConsistency(resp, req, &b); d {
+		t.Fatalf("unexpected done")
 	}
 
-	for _, tt := range tests {
-		name := fmt.Sprintf("url=%v, HTTP.AllowStale=%v", tt.url, tt.allowStale)
-		t.Run(name, func(t *testing.T) {
-			var q structs.QueryOptions
-			req, _ := http.NewRequest("GET", tt.url, nil)
-			if d := parseConsistency(resp, req, tt.allowStale, &q); d {
-				t.Fatalf("Failed to parse consistency.")
-			}
-			if got, want := q.AllowStale, tt.wantAllowStale; got != want {
-				t.Fatalf("got allowStale %v want %v", got, want)
-			}
-			if got, want := q.RequireConsistent, tt.wantRequireConsistent; got != want {
-				t.Fatalf("got requireConsistent %v want %v", got, want)
-			}
-		})
+	if !b.AllowStale {
+		t.Fatalf("Bad: %v", b)
+	}
+	if b.RequireConsistent {
+		t.Fatalf("Bad: %v", b)
+	}
+
+	b = structs.QueryOptions{}
+	req, _ = http.NewRequest("GET", "/v1/catalog/nodes?consistent", nil)
+	if d := parseConsistency(resp, req, &b); d {
+		t.Fatalf("unexpected done")
+	}
+
+	if b.AllowStale {
+		t.Fatalf("Bad: %v", b)
+	}
+	if !b.RequireConsistent {
+		t.Fatalf("Bad: %v", b)
 	}
 }
 
@@ -475,7 +470,7 @@ func TestParseConsistency_Invalid(t *testing.T) {
 	var b structs.QueryOptions
 
 	req, _ := http.NewRequest("GET", "/v1/catalog/nodes?stale&consistent", nil)
-	if d := parseConsistency(resp, req, false, &b); !d {
+	if d := parseConsistency(resp, req, &b); !d {
 		t.Fatalf("expected done")
 	}
 

website/source/docs/agent/options.html.md

@@ -757,12 +757,6 @@ Consul will not enable TLS for the HTTP API unless the `https` port has been ass
   <br><br>
   The following sub-keys are available:
 
-  * <a name="allow_stale"></a><a href="#allow_stale">`allow_stale`</a> -  Enables a stale query
-    by default for HTTP queries. This allows any Consul server, rather than only the leader, to service
-    the request. The advantage of this is you get linear read scalability with Consul servers.
-    This defaults to false. Use this with extreme caution as this will apply to *all* read queries such
-    as for the catalog and the key/value store, so clients will see potentially inconsistent results.
-
   * <a name="response_headers"></a><a href="#response_headers">`response_headers`</a>
     This object allows adding headers to the HTTP API responses.
     For example, the following config can be used to enable