73 lines
2.0 KiB
Go
73 lines
2.0 KiB
Go
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package middleware
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import (
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"context"
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"errors"
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"google.golang.org/grpc/codes"
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"google.golang.org/grpc/peer"
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"google.golang.org/grpc/status"
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"google.golang.org/grpc/tap"
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recovery "github.com/grpc-ecosystem/go-grpc-middleware/recovery"
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"github.com/hashicorp/consul/agent/consul/rate"
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)
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// ServerRateLimiterMiddleware implements a ServerInHandle function to perform
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// RPC rate limiting at the cheapest possible point (before the full request has
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// been decoded).
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func ServerRateLimiterMiddleware(limiter RateLimiter, panicHandler recovery.RecoveryHandlerFunc) tap.ServerInHandle {
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return func(ctx context.Context, info *tap.Info) (_ context.Context, retErr error) {
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// This function is called before unary and stream RPC interceptors, so we
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// must handle our own panics here.
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defer func() {
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if r := recover(); r != nil {
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retErr = panicHandler(r)
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}
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}()
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// Do not rate-limit the xDS service, it handles its own limiting.
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if info.FullMethodName == "/envoy.service.discovery.v3.AggregatedDiscoveryService/DeltaAggregatedResources" {
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return ctx, nil
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}
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peer, ok := peer.FromContext(ctx)
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if !ok {
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// This should never happen!
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return ctx, status.Error(codes.Internal, "gRPC rate limit middleware unable to read peer")
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}
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err := limiter.Allow(rate.Operation{
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Name: info.FullMethodName,
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SourceAddr: peer.Addr,
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// TODO: operation type.
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})
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switch {
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case err == nil:
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return ctx, nil
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case errors.Is(err, rate.ErrRetryElsewhere):
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return ctx, status.Error(codes.ResourceExhausted, err.Error())
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case errors.Is(err, rate.ErrRetryLater):
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return ctx, status.Error(codes.Unavailable, err.Error())
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default:
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return ctx, status.Error(codes.Internal, err.Error())
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}
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}
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}
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//go:generate mockery --name RateLimiter --inpackage
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type RateLimiter interface {
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Allow(rate.Operation) error
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}
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// NullRateLimiter returns a RateLimiter that allows every operation.
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func NullRateLimiter() RateLimiter {
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return nullRateLimiter{}
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}
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type nullRateLimiter struct{}
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func (nullRateLimiter) Allow(rate.Operation) error { return nil }
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