feat: envoy extension - http local rate limit

agent/envoyextensions/builtin/http/localratelimit/copied.go

@@ -0,0 +1,58 @@
+package localratelimit
+
+import (
+	envoy_core_v3 "github.com/envoyproxy/go-control-plane/envoy/config/core/v3"
+	envoy_listener_v3 "github.com/envoyproxy/go-control-plane/envoy/config/listener/v3"
+	envoy_http_v3 "github.com/envoyproxy/go-control-plane/envoy/extensions/filters/network/http_connection_manager/v3"
+	envoy_tls_v3 "github.com/envoyproxy/go-control-plane/envoy/extensions/transport_sockets/tls/v3"
+
+	"google.golang.org/protobuf/proto"
+	"google.golang.org/protobuf/types/known/anypb"
+)
+
+// This is copied from xds and not put into the shared package because I'm not
+// convinced it should be shared.
+
+func makeUpstreamTLSTransportSocket(tlsContext *envoy_tls_v3.UpstreamTlsContext) (*envoy_core_v3.TransportSocket, error) {
+	if tlsContext == nil {
+		return nil, nil
+	}
+	return makeTransportSocket("tls", tlsContext)
+}
+
+func makeTransportSocket(name string, config proto.Message) (*envoy_core_v3.TransportSocket, error) {
+	any, err := anypb.New(config)
+	if err != nil {
+		return nil, err
+	}
+	return &envoy_core_v3.TransportSocket{
+		Name: name,
+		ConfigType: &envoy_core_v3.TransportSocket_TypedConfig{
+			TypedConfig: any,
+		},
+	}, nil
+}
+
+func makeEnvoyHTTPFilter(name string, cfg proto.Message) (*envoy_http_v3.HttpFilter, error) {
+	any, err := anypb.New(cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	return &envoy_http_v3.HttpFilter{
+		Name:       name,
+		ConfigType: &envoy_http_v3.HttpFilter_TypedConfig{TypedConfig: any},
+	}, nil
+}
+
+func makeFilter(name string, cfg proto.Message) (*envoy_listener_v3.Filter, error) {
+	any, err := anypb.New(cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	return &envoy_listener_v3.Filter{
+		Name:       name,
+		ConfigType: &envoy_listener_v3.Filter_TypedConfig{TypedConfig: any},
+	}, nil
+}

agent/envoyextensions/builtin/http/localratelimit/ratelimit.go

@@ -0,0 +1,198 @@
+package localratelimit
+
+import (
+	"errors"
+	"fmt"
+	"time"
+
+	envoy_cluster_v3 "github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3"
+	envoy_core_v3 "github.com/envoyproxy/go-control-plane/envoy/config/core/v3"
+	envoy_listener_v3 "github.com/envoyproxy/go-control-plane/envoy/config/listener/v3"
+	envoy_route_v3 "github.com/envoyproxy/go-control-plane/envoy/config/route/v3"
+	envoy_ratelimit "github.com/envoyproxy/go-control-plane/envoy/extensions/filters/http/local_ratelimit/v3"
+	envoy_http_v3 "github.com/envoyproxy/go-control-plane/envoy/extensions/filters/network/http_connection_manager/v3"
+	envoy_type_v3 "github.com/envoyproxy/go-control-plane/envoy/type/v3"
+	envoy_resource_v3 "github.com/envoyproxy/go-control-plane/pkg/resource/v3"
+	"github.com/golang/protobuf/ptypes/wrappers"
+	"github.com/hashicorp/go-multierror"
+	"github.com/mitchellh/mapstructure"
+	"google.golang.org/protobuf/types/known/durationpb"
+
+	"github.com/hashicorp/consul/api"
+	"github.com/hashicorp/consul/envoyextensions/extensioncommon"
+)
+
+type ratelimit struct {
+	ProxyType string
+
+	// Token bucket of the rate limit
+	MaxTokens     *int
+	TokensPerFill *int
+	FillInterval  *int
+
+	// Percent of requests to be rate limited
+	FilterEnabled  *uint32
+	FilterEnforced *uint32
+}
+
+var _ extensioncommon.BasicExtension = (*ratelimit)(nil)
+
+// Constructor follows a specific function signature required for the extension registration.
+func Constructor(ext api.EnvoyExtension) (extensioncommon.EnvoyExtender, error) {
+	var r ratelimit
+	if name := ext.Name; name != api.BuiltinLocalRatelimitExtension {
+		return nil, fmt.Errorf("expected extension name 'ratelimit' but got %q", name)
+	}
+
+	if err := r.fromArguments(ext.Arguments); err != nil {
+		return nil, err
+	}
+
+	return &extensioncommon.BasicEnvoyExtender{
+		Extension: &r,
+	}, nil
+}
+
+func (r *ratelimit) fromArguments(args map[string]interface{}) error {
+	if err := mapstructure.Decode(args, r); err != nil {
+		return fmt.Errorf("error decoding extension arguments: %v", err)
+	}
+	return r.validate()
+}
+
+func (r *ratelimit) validate() error {
+	var resultErr error
+
+	// NOTE: Envoy requires FillInterval value must be greater than 0.
+	// If unset, it is considered as 0.
+	if r.FillInterval == nil {
+		resultErr = multierror.Append(resultErr, fmt.Errorf("FillInterval(in second) is missing"))
+	} else if *r.FillInterval <= 0 {
+		resultErr = multierror.Append(resultErr, fmt.Errorf("FillInterval(in second) must be greater than 0, got %d", *r.FillInterval))
+	}
+
+	// NOTE: Envoy requires MaxToken value must be greater than 0.
+	// If unset, it is considered as 0.
+	if r.MaxTokens == nil {
+		resultErr = multierror.Append(resultErr, fmt.Errorf("MaxTokens is missing"))
+	} else if *r.MaxTokens <= 0 {
+		resultErr = multierror.Append(resultErr, fmt.Errorf("MaxTokens must be greater than 0, got %d", r.MaxTokens))
+	}
+
+	// TokensPerFill is allowed to unset. In this case, envoy
+	// uses its default value, which is 1.
+	if r.TokensPerFill != nil && *r.TokensPerFill <= 0 {
+		resultErr = multierror.Append(resultErr, fmt.Errorf("TokensPerFill must be greater than 0, got %d", *r.TokensPerFill))
+	}
+
+	if err := validateProxyType(r.ProxyType); err != nil {
+		resultErr = multierror.Append(resultErr, err)
+	}
+
+	return resultErr
+}
+
+// CanApply determines if the extension can apply to the given extension configuration.
+func (p *ratelimit) CanApply(config *extensioncommon.RuntimeConfig) bool {
+	// rate limit is only applied to the service itself since the limit is
+	// aggregated from all downstream connections.
+	return string(config.Kind) == p.ProxyType && !config.IsUpstream()
+}
+
+// PatchRoute does nothing.
+func (p ratelimit) PatchRoute(_ *extensioncommon.RuntimeConfig, route *envoy_route_v3.RouteConfiguration) (*envoy_route_v3.RouteConfiguration, bool, error) {
+	return route, false, nil
+}
+
+// PatchCluster does nothing.
+func (p ratelimit) PatchCluster(_ *extensioncommon.RuntimeConfig, c *envoy_cluster_v3.Cluster) (*envoy_cluster_v3.Cluster, bool, error) {
+	return c, false, nil
+}
+
+// PatchFilter inserts a http local rate_limit filter at the head of
+// envoy.filters.network.http_connection_manager filters
+func (p ratelimit) PatchFilter(_ *extensioncommon.RuntimeConfig, filter *envoy_listener_v3.Filter) (*envoy_listener_v3.Filter, bool, error) {
+	if filter.Name != "envoy.filters.network.http_connection_manager" {
+		return filter, false, nil
+	}
+	if typedConfig := filter.GetTypedConfig(); typedConfig == nil {
+		return filter, false, errors.New("error getting typed config for http filter")
+	}
+
+	config := envoy_resource_v3.GetHTTPConnectionManager(filter)
+	if config == nil {
+		return filter, false, errors.New("error unmarshalling filter")
+	}
+
+	tokenBucket := envoy_type_v3.TokenBucket{}
+
+	if p.TokensPerFill != nil {
+		tokenBucket.TokensPerFill = &wrappers.UInt32Value{
+			Value: uint32(*p.TokensPerFill),
+		}
+	}
+	if p.MaxTokens != nil {
+		tokenBucket.MaxTokens = uint32(*p.MaxTokens)
+	}
+
+	if p.FillInterval != nil {
+		tokenBucket.FillInterval = durationpb.New(time.Duration(*p.FillInterval) * time.Second)
+	}
+
+	var FilterEnabledDefault *envoy_core_v3.RuntimeFractionalPercent
+	if p.FilterEnabled != nil {
+		FilterEnabledDefault = &envoy_core_v3.RuntimeFractionalPercent{
+			DefaultValue: &envoy_type_v3.FractionalPercent{
+				Numerator:   *p.FilterEnabled,
+				Denominator: envoy_type_v3.FractionalPercent_HUNDRED,
+			},
+		}
+	}
+
+	var FilterEnforcedDefault *envoy_core_v3.RuntimeFractionalPercent
+	if p.FilterEnforced != nil {
+		FilterEnforcedDefault = &envoy_core_v3.RuntimeFractionalPercent{
+			DefaultValue: &envoy_type_v3.FractionalPercent{
+				Numerator:   *p.FilterEnforced,
+				Denominator: envoy_type_v3.FractionalPercent_HUNDRED,
+			},
+		}
+	}
+
+	ratelimitHttpFilter, err := makeEnvoyHTTPFilter(
+		"envoy.filters.http.local_ratelimit",
+		&envoy_ratelimit.LocalRateLimit{
+			TokenBucket:    &tokenBucket,
+			StatPrefix:     "local_ratelimit",
+			FilterEnabled:  FilterEnabledDefault,
+			FilterEnforced: FilterEnforcedDefault,
+		},
+	)
+
+	if err != nil {
+		return filter, false, err
+	}
+
+	changedFilters := make([]*envoy_http_v3.HttpFilter, 0, len(config.HttpFilters)+1)
+
+	// The ratelimitHttpFilter is inserted as the first element of the http
+	// filter chain.
+	changedFilters = append(changedFilters, ratelimitHttpFilter)
+	changedFilters = append(changedFilters, config.HttpFilters...)
+	config.HttpFilters = changedFilters
+
+	newFilter, err := makeFilter("envoy.filters.network.http_connection_manager", config)
+	if err != nil {
+		return filter, false, errors.New("error making new filter")
+	}
+
+	return newFilter, true, nil
+}
+
+func validateProxyType(t string) error {
+	if t != "connect-proxy" {
+		return fmt.Errorf("unexpected ProxyType %q", t)
+	}
+
+	return nil
+}