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 (
	// 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)

	// 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 disabled by default, but can be enabled by setting
	// the env variable "GRPC_GO_EXPERIMENTAL_CASE_SENSITIVE_BALANCER_REGISTRIES"
	// to "true".
	//
	// TODO: After 2 releases, we will enable the env var by default.
	CaseSensitiveBalancerRegistries = boolFromEnv("GRPC_GO_EXPERIMENTAL_CASE_SENSITIVE_BALANCER_REGISTRIES", false)

	// 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)
)

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)
)

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 is true if gRPC should parse custom Metadata
	// configuring use of an HTTP CONNECT proxy via xDS from cluster resources.
	// 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)
)