snapshot of https://github.com/grpc/grpc-go.git (master, 2026-09-15; blobs > 131072B omitted)

internal/envconfig/envconfig.go

@@ -0,0 +1,244 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package envconfig contains grpc settings configured by environment variables.
+package envconfig
+
+import (
+	"os"
+	"strconv"
+	"strings"
+)
+
+var (
+	// EnableTXTServiceConfig is set if the DNS resolver should perform TXT
+	// lookups for service config ("GRPC_ENABLE_TXT_SERVICE_CONFIG" is not
+	// "false").
+	EnableTXTServiceConfig = boolFromEnv("GRPC_ENABLE_TXT_SERVICE_CONFIG", true)
+
+	// TXTErrIgnore is set if TXT errors should be ignored
+	// ("GRPC_GO_IGNORE_TXT_ERRORS" is not "false").
+	TXTErrIgnore = boolFromEnv("GRPC_GO_IGNORE_TXT_ERRORS", true)
+
+	// RingHashCap indicates the maximum ring size which defaults to 4096
+	// entries but may be overridden by setting the environment variable
+	// "GRPC_RING_HASH_CAP".  This does not override the default bounds
+	// checking which NACKs configs specifying ring sizes > 8*1024*1024 (~8M).
+	RingHashCap = uint64FromEnv("GRPC_RING_HASH_CAP", 4096, 1, 8*1024*1024)
+
+	// ALTSMaxConcurrentHandshakes is the maximum number of concurrent ALTS
+	// handshakes that can be performed.
+	ALTSMaxConcurrentHandshakes = uint64FromEnv("GRPC_ALTS_MAX_CONCURRENT_HANDSHAKES", 100, 1, 100)
+
+	// EnforceALPNEnabled is set if TLS connections to servers with ALPN disabled
+	// should be rejected. The HTTP/2 protocol requires ALPN to be enabled, this
+	// option is present for backward compatibility. This option may be overridden
+	// by setting the environment variable "GRPC_ENFORCE_ALPN_ENABLED" to "true"
+	// or "false".
+	EnforceALPNEnabled = boolFromEnv("GRPC_ENFORCE_ALPN_ENABLED", true)
+
+	// XDSEndpointHashKeyBackwardCompat controls the parsing of the endpoint hash
+	// key from EDS LbEndpoint metadata. Endpoint hash keys can be disabled by
+	// setting "GRPC_XDS_ENDPOINT_HASH_KEY_BACKWARD_COMPAT" to "true". A future
+	// release will remove this environment variable, enabling the new behavior
+	// unconditionally.
+	XDSEndpointHashKeyBackwardCompat = boolFromEnv("GRPC_XDS_ENDPOINT_HASH_KEY_BACKWARD_COMPAT", false)
+
+	// LabelServerGoroutines controls setting [runtime/pprof.Labels] on the
+	// goroutines spawned by [grpc.Server] type.
+	// For now, this is limited to the goroutines spawned to handle incoming
+	// requests on the server.
+	// Set "GRPC_GO_SERVER_GOROUTINE_LABELS" to "grpc.method=true" to
+	// enable this grpc.method label, or "all" to enable all valid labels.
+	// This variable is a bit-field.
+	LabelServerGoroutines = goroutineLabelsFromEnv("GRPC_GO_SERVER_GOROUTINE_LABELS", 0)
+
+	// RingHashSetRequestHashKey is set if the ring hash balancer can get the
+	// request hash header by setting the "requestHashHeader" field, according
+	// to gRFC A76. It can be disabled by setting the environment variable
+	// "GRPC_EXPERIMENTAL_RING_HASH_SET_REQUEST_HASH_KEY" to "false".
+	RingHashSetRequestHashKey = boolFromEnv("GRPC_EXPERIMENTAL_RING_HASH_SET_REQUEST_HASH_KEY", true)
+
+	// ALTSHandshakerKeepaliveParams is set if we should add the
+	// KeepaliveParams when dial the ALTS handshaker service.
+	ALTSHandshakerKeepaliveParams = boolFromEnv("GRPC_EXPERIMENTAL_ALTS_HANDSHAKER_KEEPALIVE_PARAMS", false)
+
+	// EnableDefaultPortForProxyTarget controls whether the resolver adds a default port 443
+	// to a target address that lacks one. This flag only has an effect when all of
+	// the following conditions are met:
+	//   - A connect proxy is being used.
+	//   - Target resolution is disabled.
+	//   - The DNS resolver is being used.
+	EnableDefaultPortForProxyTarget = boolFromEnv("GRPC_EXPERIMENTAL_ENABLE_DEFAULT_PORT_FOR_PROXY_TARGET", true)
+
+	// CaseSensitiveBalancerRegistries is set if the balancer registry should be
+	// case-sensitive. This is enabled by default, but can be disabled by setting
+	// the env variable "GRPC_GO_EXPERIMENTAL_CASE_SENSITIVE_BALANCER_REGISTRIES"
+	// to "false".
+	//
+	// This env varible will be removed in release v1.82.0.
+	CaseSensitiveBalancerRegistries = boolFromEnv("GRPC_GO_EXPERIMENTAL_CASE_SENSITIVE_BALANCER_REGISTRIES", true)
+
+	// XDSAuthorityRewrite indicates whether xDS authority rewriting is enabled.
+	// This feature is defined in gRFC A81 and is enabled by setting the
+	// environment variable GRPC_EXPERIMENTAL_XDS_AUTHORITY_REWRITE to "true".
+	XDSAuthorityRewrite = boolFromEnv("GRPC_EXPERIMENTAL_XDS_AUTHORITY_REWRITE", false)
+
+	// PickFirstWeightedShuffling indicates whether weighted endpoint shuffling
+	// is enabled in the pick_first LB policy, as defined in gRFC A113. This
+	// feature can be disabled by setting the environment variable
+	// GRPC_EXPERIMENTAL_PF_WEIGHTED_SHUFFLING to "false".
+	PickFirstWeightedShuffling = boolFromEnv("GRPC_EXPERIMENTAL_PF_WEIGHTED_SHUFFLING", true)
+
+	// XDSRecoverPanicInResourceParsing indicates whether the xdsclient should
+	// recover from panics while parsing xDS resources.
+	//
+	// This feature can be disabled (e.g. for fuzz testing) by setting the
+	// environment variable "GRPC_GO_EXPERIMENTAL_XDS_RESOURCE_PANIC_RECOVERY"
+	// to "false".
+	XDSRecoverPanicInResourceParsing = boolFromEnv("GRPC_GO_EXPERIMENTAL_XDS_RESOURCE_PANIC_RECOVERY", true)
+
+	// EnablePriorityLBChildPolicyCache controls whether the priority balancer
+	// should cache child balancers that are removed from the LB policy config,
+	// for a period of 15 minutes. This is disabled by default, but can be
+	// enabled by setting the env variable
+	// GRPC_EXPERIMENTAL_ENABLE_PRIORITY_LB_CHILD_POLICY_CACHE to true.
+	EnablePriorityLBChildPolicyCache = boolFromEnv("GRPC_EXPERIMENTAL_ENABLE_PRIORITY_LB_CHILD_POLICY_CACHE", false)
+
+	// Enable8KBDefaultHeaderListSize indicates that default maximum header list
+	// size is restricted to 8KB. This is disabled by default, but can be enabled
+	// by setting the environment variable
+	// "GRPC_GO_EXPERIMENTAL_ENABLE_8KB_DEFAULT_HEADER_LIST_SIZE" to "true".
+	// When disabled, the default maximum header list size of 16MB is used.
+	//
+	// When enabled, RPCs with a total size of headers exceeding 8KB will fail
+	// unless explicitly configured otherwise by the user.
+	//
+	// TODO: In release v1.82.0, env var will be enabled by default.
+	Enable8KBDefaultHeaderListSize = boolFromEnv("GRPC_GO_EXPERIMENTAL_ENABLE_8KB_DEFAULT_HEADER_LIST_SIZE", false)
+
+	// EnableHTTPFramerReadBufferPooling enables the use of the
+	// readyreader.Reader interface to perform non-memory-pinning reads,
+	// provided the underlying net.Conn supports it. This reduces memory usage
+	// when subchannels are idle.
+	//
+	// This environment variable serves as an escape hatch to disable the
+	// feature if unforeseen issues arise, and it will be removed in a future
+	// release.
+	EnableHTTPFramerReadBufferPooling = boolFromEnv("GRPC_GO_EXPERIMENTAL_HTTP_FRAMER_READ_BUFFER_POOLING", true)
+
+	// ControlBufferThrottleLimit is the maximum number of control frames that can
+	// be queued in the control buffer before throttling is applied. The value
+	// must be between 1 and 10,000, and is set to 100 by default.
+	//
+	// This environment variable serves as an escape hatch to increase the
+	// throttling limit if unforeseen issues arise, and it will be removed in a
+	// future release.
+	//
+	// TODO: Remove this env var once v1.83.0 is released.
+	ControlBufferThrottleLimit = uint64FromEnv("GRPC_GO_EXPERIMENTAL_CONTROL_BUFFER_THROTTLE_LIMIT", 100, 1, 10000)
+
+	// ALTSMaxFrameSize is the maximum frame size for ALTS in bytes.
+	// This can be overridden by setting the environment variable
+	// "GRPC_GO_EXPERIMENTAL_ALTS_MAX_FRAME_SIZE" (min: 4096, max: 512*1024, capped at
+	// 512KiB to match altsWriteBufferMaxSize in
+	// credentials/alts/internal/conn/record.go).
+	ALTSMaxFrameSize = uint64FromEnv("GRPC_GO_EXPERIMENTAL_ALTS_MAX_FRAME_SIZE", 4096, 4096, 512*1024)
+
+	// EnableReceiveBufferCompaction enables the compaction of data buffers
+	// to reduce the number of buffers in the receive buffer.
+	//
+	// This environment variable serves as an escape hatch to disable the
+	// feature if unforeseen issues arise, and it will be removed in a future
+	// release.
+	//
+	// TODO: Remove this env var once v1.85.0 is released.
+	EnableReceiveBufferCompaction = boolFromEnv("GRPC_GO_EXPERIMENTAL_ENABLE_RECEIVE_BUFFER_COMPACTION", true)
+)
+
+func boolFromEnv(envVar string, def bool) bool {
+	if def {
+		// The default is true; return true unless the variable is "false".
+		return !strings.EqualFold(os.Getenv(envVar), "false")
+	}
+	// The default is false; return false unless the variable is "true".
+	return strings.EqualFold(os.Getenv(envVar), "true")
+}
+
+func uint64FromEnv(envVar string, def, min, max uint64) uint64 {
+	v, err := strconv.ParseUint(os.Getenv(envVar), 10, 64)
+	if err != nil {
+		return def
+	}
+	if v < min {
+		return min
+	}
+	if v > max {
+		return max
+	}
+	return v
+}
+
+// GoroutineLabels is a bitfield indicating which goroutine labels are enabled.
+type GoroutineLabels uint16
+
+func goroutineLabelsFromEnv(envVar string, def GoroutineLabels) GoroutineLabels {
+	val := def
+	v := os.Getenv(envVar)
+	if strings.EqualFold(v, "all") {
+		return AllGoroutineLabels
+	} else if strings.EqualFold(v, "none") {
+		return 0
+	}
+	for s := range strings.SplitSeq(v, ",") {
+		s = strings.TrimSpace(s)
+		if len(s) == 0 {
+			continue
+		}
+		pre, post, ok := strings.Cut(s, "=")
+		if !ok {
+			// no equals sign
+			continue
+		}
+		post = strings.TrimSpace(post)
+		pre = strings.TrimSpace(pre)
+		bitDesignator := GoroutineLabels(0)
+		switch {
+		case strings.EqualFold(pre, "grpc.method"):
+			bitDesignator = GoroutineLabelServerMethod
+		default:
+			continue
+		}
+		if strings.EqualFold(post, "true") {
+			val |= bitDesignator
+		} else if strings.EqualFold(post, "false") {
+			val &^= bitDesignator
+		}
+	}
+	return val
+}
+
+const (
+	// GoroutineLabelServerMethod sets the grpc.method label on new
+	// server-side gRPC streams.
+	GoroutineLabelServerMethod GoroutineLabels = 1 << iota
+)
+
+// AllGoroutineLabels is an or'd together bitfield of all valid GoroutineLabels
+// constant values (above).
+const AllGoroutineLabels = GoroutineLabelServerMethod

internal/envconfig/envconfig_test.go

@@ -0,0 +1,218 @@
+/*
+ *
+ * Copyright 2022 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package envconfig
+
+import (
+	"os"
+	"testing"
+
+	"google.golang.org/grpc/internal/grpctest"
+)
+
+type s struct {
+	grpctest.Tester
+}
+
+func Test(t *testing.T) {
+	grpctest.RunSubTests(t, s{})
+}
+
+func (s) TestUint64FromEnv(t *testing.T) {
+	var testCases = []struct {
+		name          string
+		val           string
+		def, min, max uint64
+		want          uint64
+	}{
+		{
+			name: "error parsing",
+			val:  "asdf", def: 5, want: 5,
+		}, {
+			name: "unset",
+			val:  "", def: 5, want: 5,
+		}, {
+			name: "too low",
+			val:  "5", min: 10, want: 10,
+		}, {
+			name: "too high",
+			val:  "5", max: 2, want: 2,
+		}, {
+			name: "in range",
+			val:  "17391", def: 13000, min: 12000, max: 18000, want: 17391,
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			const testVar = "testvar"
+			if tc.val == "" {
+				os.Unsetenv(testVar)
+			} else {
+				os.Setenv(testVar, tc.val)
+			}
+			if got := uint64FromEnv(testVar, tc.def, tc.min, tc.max); got != tc.want {
+				t.Errorf("uint64FromEnv(%q(=%q), %v, %v, %v) = %v; want %v", testVar, tc.val, tc.def, tc.min, tc.max, got, tc.want)
+			}
+		})
+	}
+}
+
+func (s) TestBoolFromEnv(t *testing.T) {
+	var testCases = []struct {
+		val  string
+		def  bool
+		want bool
+	}{
+		{val: "", def: true, want: true},
+		{val: "", def: false, want: false},
+		{val: "true", def: true, want: true},
+		{val: "true", def: false, want: true},
+		{val: "false", def: true, want: false},
+		{val: "false", def: false, want: false},
+		{val: "asdf", def: true, want: true},
+		{val: "asdf", def: false, want: false},
+	}
+	for _, tc := range testCases {
+		t.Run("", func(t *testing.T) {
+			const testVar = "testvar"
+			if tc.val == "" {
+				os.Unsetenv(testVar)
+			} else {
+				os.Setenv(testVar, tc.val)
+			}
+			if got := boolFromEnv(testVar, tc.def); got != tc.want {
+				t.Errorf("boolFromEnv(%q(=%q), %v) = %v; want %v", testVar, tc.val, tc.def, got, tc.want)
+			}
+		})
+	}
+}
+
+func (s) TestGoroutineLabelsFromEnv(t *testing.T) {
+	var testCases = []struct {
+		name string
+		val  string
+		def  GoroutineLabels
+		want GoroutineLabels
+	}{
+		{
+			name: "unset_env_non-zero_default",
+			val:  "",
+			def:  GoroutineLabelServerMethod,
+			want: GoroutineLabelServerMethod,
+		}, {
+			name: "unset_env_zero_default",
+			val:  "",
+			def:  0,
+			want: 0,
+		}, {
+			name: "force-enable_zero_default",
+			val:  "grpc.method=true",
+			def:  0,
+			want: GoroutineLabelServerMethod,
+		}, {
+			name: "force-enable_zero_default_all_caps",
+			val:  "grpc.method=TRUE",
+			def:  0,
+			want: GoroutineLabelServerMethod,
+		}, {
+			name: "force-enable_zero_default_with_whitespace",
+			val:  " grpc.method\t= true",
+			def:  0,
+			want: GoroutineLabelServerMethod,
+		}, {
+			name: "force-enable_zero_default_with_other_garbage",
+			val:  "grpc.method=true,foobar",
+			def:  0,
+			want: GoroutineLabelServerMethod,
+		}, {
+			name: "force-enable_mixed_case_zero_default_with_other_garbage",
+			val:  "grpc.method=tRuE,foobar",
+			def:  0,
+			want: GoroutineLabelServerMethod,
+		}, {
+			name: "force-disable_zero_default",
+			val:  "grpc.method=false",
+			def:  0,
+			want: 0,
+		}, {
+			name: "force-disable_non-zero_default",
+			val:  "grpc.method=false",
+			def:  GoroutineLabelServerMethod,
+			want: 0,
+		}, {
+			name: "force-disable_non-zero_default_all_caps",
+			val:  "grpc.method=FALSE",
+			def:  GoroutineLabelServerMethod,
+			want: 0,
+		}, {
+			name: "force-disable_non-zero_default_mixed_case",
+			val:  "grpc.method=fAlSe",
+			def:  GoroutineLabelServerMethod,
+			want: 0,
+		}, {
+			name: "unknown_val_no_equal",
+			val:  "grpc.unknown.garbage",
+			def:  GoroutineLabelServerMethod,
+			want: GoroutineLabelServerMethod,
+		}, {
+			name: "unknown_val",
+			val:  "grpc.unknown.garbage=fooble",
+			def:  GoroutineLabelServerMethod,
+			want: GoroutineLabelServerMethod,
+		}, {
+			name: "all_with_empty_default",
+			val:  "all",
+			def:  0,
+			want: AllGoroutineLabels,
+		}, {
+			name: "all_with_server_method_default",
+			val:  "all",
+			def:  GoroutineLabelServerMethod,
+			want: AllGoroutineLabels,
+		}, {
+			name: "none_with_empty_default",
+			val:  "none",
+			def:  0,
+			want: 0,
+		}, {
+			name: "none_with_server_method_default",
+			val:  "none",
+			def:  GoroutineLabelServerMethod,
+			want: 0,
+		}, {
+			name: "unparseable_rhs",
+			val:  "grpc.method=quux",
+			def:  GoroutineLabelServerMethod,
+			want: GoroutineLabelServerMethod,
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			const testVar = "testvar"
+			if tc.val == "" {
+				os.Unsetenv(testVar)
+			} else {
+				os.Setenv(testVar, tc.val)
+			}
+			if got := goroutineLabelsFromEnv(testVar, tc.def); got != tc.want {
+				t.Errorf("goroutineLabelsFromEnv(%q(=%q), %v) = %v; want %v", testVar, tc.val, tc.def, got, tc.want)
+			}
+		})
+	}
+
+}

internal/envconfig/observability.go

@@ -0,0 +1,42 @@
+/*
+ *
+ * Copyright 2022 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package envconfig
+
+import "os"
+
+const (
+	envObservabilityConfig     = "GRPC_GCP_OBSERVABILITY_CONFIG"
+	envObservabilityConfigFile = "GRPC_GCP_OBSERVABILITY_CONFIG_FILE"
+)
+
+var (
+	// ObservabilityConfig is the json configuration for the gcp/observability
+	// package specified directly in the envObservabilityConfig env var.
+	//
+	// This is used in the 1.0 release of gcp/observability, and thus must not be
+	// deleted or changed.
+	ObservabilityConfig = os.Getenv(envObservabilityConfig)
+	// ObservabilityConfigFile is the json configuration for the
+	// gcp/observability specified in a file with the location specified in
+	// envObservabilityConfigFile env var.
+	//
+	// This is used in the 1.0 release of gcp/observability, and thus must not be
+	// deleted or changed.
+	ObservabilityConfigFile = os.Getenv(envObservabilityConfigFile)
+)

internal/envconfig/xds.go

@@ -0,0 +1,106 @@
+/*
+ *
+ * Copyright 2020 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package envconfig
+
+import (
+	"os"
+)
+
+const (
+	// XDSBootstrapFileNameEnv is the env variable to set bootstrap file name.
+	// Do not use this and read from env directly. Its value is read and kept in
+	// variable XDSBootstrapFileName.
+	//
+	// When both bootstrap FileName and FileContent are set, FileName is used.
+	XDSBootstrapFileNameEnv = "GRPC_XDS_BOOTSTRAP"
+	// XDSBootstrapFileContentEnv is the env variable to set bootstrap file
+	// content. Do not use this and read from env directly. Its value is read
+	// and kept in variable XDSBootstrapFileContent.
+	//
+	// When both bootstrap FileName and FileContent are set, FileName is used.
+	XDSBootstrapFileContentEnv = "GRPC_XDS_BOOTSTRAP_CONFIG"
+)
+
+var (
+	// XDSBootstrapFileName holds the name of the file which contains xDS
+	// bootstrap configuration. Users can specify the location of the bootstrap
+	// file by setting the environment variable "GRPC_XDS_BOOTSTRAP".
+	//
+	// When both bootstrap FileName and FileContent are set, FileName is used.
+	XDSBootstrapFileName = os.Getenv(XDSBootstrapFileNameEnv)
+	// XDSBootstrapFileContent holds the content of the xDS bootstrap
+	// configuration. Users can specify the bootstrap config by setting the
+	// environment variable "GRPC_XDS_BOOTSTRAP_CONFIG".
+	//
+	// When both bootstrap FileName and FileContent are set, FileName is used.
+	XDSBootstrapFileContent = os.Getenv(XDSBootstrapFileContentEnv)
+
+	// C2PResolverTestOnlyTrafficDirectorURI is the TD URI for testing.
+	C2PResolverTestOnlyTrafficDirectorURI = os.Getenv("GRPC_TEST_ONLY_GOOGLE_C2P_RESOLVER_TRAFFIC_DIRECTOR_URI")
+
+	// XDSDualstackEndpointsEnabled is true if gRPC should read the
+	// "additional addresses" in the xDS endpoint resource.
+	XDSDualstackEndpointsEnabled = boolFromEnv("GRPC_EXPERIMENTAL_XDS_DUALSTACK_ENDPOINTS", true)
+
+	// XDSSystemRootCertsEnabled is true when xDS enabled gRPC clients can use
+	// the system's default root certificates for TLS certificate validation.
+	// For more details, see:
+	// https://github.com/grpc/proposal/blob/master/A82-xds-system-root-certs.md.
+	XDSSystemRootCertsEnabled = boolFromEnv("GRPC_EXPERIMENTAL_XDS_SYSTEM_ROOT_CERTS", false)
+
+	// XDSSPIFFEEnabled controls if SPIFFE Bundle Maps can be used as roots of
+	// trust.  For more details, see:
+	// https://github.com/grpc/proposal/blob/master/A87-mtls-spiffe-support.md
+	XDSSPIFFEEnabled = boolFromEnv("GRPC_EXPERIMENTAL_XDS_MTLS_SPIFFE", false)
+
+	// XDSHTTPConnectEnabled controls support for dynamic HTTP CONNECT proxying
+	// configured via the xDS control plane. For more details, see:
+	// https://github.com/grpc/proposal/blob/master/A86-xds-http-connect.md
+	XDSHTTPConnectEnabled = boolFromEnv("GRPC_EXPERIMENTAL_XDS_HTTP_CONNECT", false)
+
+	// XDSBootstrapCallCredsEnabled controls if call credentials can be used in
+	// xDS bootstrap configuration via the `call_creds` field. For more details,
+	// see: https://github.com/grpc/proposal/blob/master/A97-xds-jwt-call-creds.md
+	XDSBootstrapCallCredsEnabled = boolFromEnv("GRPC_EXPERIMENTAL_XDS_BOOTSTRAP_CALL_CREDS", false)
+
+	// XDSSNIEnabled controls if gRPC should send SNI information in xDS
+	// configured TLS handshakes. For more details, see:
+	// https://github.com/grpc/proposal/blob/master/A101-SNI-setting-and-SNI-SAN-validation.md
+	XDSSNIEnabled = boolFromEnv("GRPC_EXPERIMENTAL_XDS_SNI", false)
+
+	// XDSORCAToLRSPropEnabled controls whether ORCA metrics are explicitly
+	// filtered and prefix-propagated to the LRS server. For more details, see:
+	// https://github.com/grpc/proposal/blob/master/A85-lrs-custom-metrics-changes.md
+	XDSORCAToLRSPropEnabled = boolFromEnv("GRPC_EXPERIMENTAL_XDS_ORCA_LRS_PROPAGATION", true)
+
+	// XDSClientExtProcEnabled indicates whether ExtProc filter is enabled on
+	// the client side. For more details, see:
+	// https://github.com/grpc/proposal/blob/master/A93-xds-ext-proc.md
+	XDSClientExtProcEnabled = boolFromEnv("GRPC_EXPERIMENTAL_XDS_EXT_PROC_ON_CLIENT", false)
+
+	// GCPAuthenticationFilterEnabled enables the xDS GCP Authentication
+	// filter. For more details, see:
+	// https://github.com/grpc/proposal/blob/master/A83-xds-gcp-authn-filter.md
+	GCPAuthenticationFilterEnabled = boolFromEnv("GRPC_EXPERIMENTAL_XDS_GCP_AUTHENTICATION_FILTER", false)
+
+	// XDSClientExtAuthzEnabled indicates whether the external authorization
+	// filter is enabled on the client side. For more details, see:
+	// https://github.com/grpc/proposal/blob/master/A92-xds-ext-authz.md
+	XDSClientExtAuthzEnabled = boolFromEnv("GRPC_EXPERIMENTAL_XDS_EXT_AUTHZ_ON_CLIENT", false)
+)