123 lines
3.3 KiB
Go
123 lines
3.3 KiB
Go
// Copyright (C) 2019 Storj Labs, Inc.
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// See LICENSE for copying information.
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package transport
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import (
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"context"
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"net"
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"time"
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"google.golang.org/grpc"
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"storj.io/storj/internal/memory"
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"storj.io/storj/pkg/identity"
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"storj.io/storj/pkg/pb"
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)
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// SimulatedNetwork allows creating connections that try to simulated realistic network conditions.
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type SimulatedNetwork struct {
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DialLatency time.Duration
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BytesPerSecond memory.Size
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}
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// NewClient wraps an exiting client with the simulated network params.
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func (network *SimulatedNetwork) NewClient(client Client) Client {
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return &slowTransport{
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client: client,
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network: network,
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}
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}
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// slowTransport is a slow version of transport
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type slowTransport struct {
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client Client
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network *SimulatedNetwork
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}
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// DialNode dials a node with latency
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func (client *slowTransport) DialNode(ctx context.Context, node *pb.Node, opts ...grpc.DialOption) (*grpc.ClientConn, error) {
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return client.client.DialNode(ctx, node, append(client.network.DialOptions(), opts...)...)
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}
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// DialAddress dials an address with latency
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func (client *slowTransport) DialAddress(ctx context.Context, address string, opts ...grpc.DialOption) (*grpc.ClientConn, error) {
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return client.client.DialAddress(ctx, address, append(client.network.DialOptions(), opts...)...)
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}
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// Identity for slowTransport
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func (client *slowTransport) Identity() *identity.FullIdentity {
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return client.client.Identity()
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}
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// WithObservers calls WithObservers for slowTransport
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func (client *slowTransport) WithObservers(obs ...Observer) *Transport {
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return client.client.WithObservers(obs...)
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}
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// DialOptions returns options such that it will use simulated network parameters
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func (network *SimulatedNetwork) DialOptions() []grpc.DialOption {
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return []grpc.DialOption{grpc.WithContextDialer(network.GRPCDialContext)}
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}
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// GRPCDialContext implements DialContext that is suitable for `grpc.WithContextDialer`
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func (network *SimulatedNetwork) GRPCDialContext(ctx context.Context, address string) (net.Conn, error) {
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timer := time.NewTimer(network.DialLatency)
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defer timer.Stop()
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select {
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case <-ctx.Done():
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return nil, ctx.Err()
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case <-timer.C:
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}
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conn, err := (&net.Dialer{}).DialContext(ctx, "tcp", address)
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if err != nil {
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return conn, err
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}
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if network.BytesPerSecond == 0 {
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return conn, err
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}
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return &simulatedConn{network, conn}, nil
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}
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// simulatedConn implements slow reading and writing to the connection
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//
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// This does not handle read deadline and write deadline properly.
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type simulatedConn struct {
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network *SimulatedNetwork
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net.Conn
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}
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// delay sleeps specified amount of time
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func (conn *simulatedConn) delay(actualWait time.Duration, bytes int) {
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expectedWait := time.Duration(bytes * int(time.Second) / conn.network.BytesPerSecond.Int())
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if actualWait < expectedWait {
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time.Sleep(expectedWait - actualWait)
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}
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}
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// Read reads data from the connection.
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func (conn *simulatedConn) Read(b []byte) (n int, err error) {
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start := time.Now()
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n, err = conn.Conn.Read(b)
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if err == context.Canceled {
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return n, err
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}
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conn.delay(time.Since(start), n)
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return n, err
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}
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// Write writes data to the connection.
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func (conn *simulatedConn) Write(b []byte) (n int, err error) {
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start := time.Now()
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n, err = conn.Conn.Write(b)
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if err == context.Canceled {
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return n, err
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}
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conn.delay(time.Since(start), n)
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return n, err
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}
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