01a513a496
This diff refactors the DNSTransport model to receive in input a DNSQuery and return in output a DNSResponse. The design of DNSQuery and DNSResponse takes into account the use case of a transport using getaddrinfo, meaning that we don't need to serialize and deserialize messages when using getaddrinfo. The current codebase does not use a getaddrinfo transport, but I wrote one such a transport in the Websteps Winter 2021 prototype (https://github.com/bassosimone/websteps-illustrated/). The design conversation that lead to producing this diff is https://github.com/ooni/probe/issues/2099
88 lines
2.1 KiB
Go
88 lines
2.1 KiB
Go
package resolver
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import (
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"context"
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"time"
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"github.com/ooni/probe-cli/v3/internal/engine/netx/trace"
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"github.com/ooni/probe-cli/v3/internal/model"
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)
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// SaverResolver is a resolver that saves events
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type SaverResolver struct {
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model.Resolver
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Saver *trace.Saver
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}
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// LookupHost implements Resolver.LookupHost
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func (r SaverResolver) LookupHost(ctx context.Context, hostname string) ([]string, error) {
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start := time.Now()
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r.Saver.Write(trace.Event{
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Address: r.Resolver.Address(),
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Hostname: hostname,
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Name: "resolve_start",
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Proto: r.Resolver.Network(),
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Time: start,
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})
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addrs, err := r.Resolver.LookupHost(ctx, hostname)
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stop := time.Now()
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r.Saver.Write(trace.Event{
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Addresses: addrs,
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Address: r.Resolver.Address(),
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Duration: stop.Sub(start),
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Err: err,
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Hostname: hostname,
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Name: "resolve_done",
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Proto: r.Resolver.Network(),
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Time: stop,
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})
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return addrs, err
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}
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// SaverDNSTransport is a DNS transport that saves events
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type SaverDNSTransport struct {
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model.DNSTransport
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Saver *trace.Saver
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}
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// RoundTrip implements RoundTripper.RoundTrip
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func (txp SaverDNSTransport) RoundTrip(
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ctx context.Context, query model.DNSQuery) (model.DNSResponse, error) {
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start := time.Now()
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txp.Saver.Write(trace.Event{
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Address: txp.Address(),
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DNSQuery: txp.maybeQueryBytes(query),
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Name: "dns_round_trip_start",
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Proto: txp.Network(),
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Time: start,
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})
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response, err := txp.DNSTransport.RoundTrip(ctx, query)
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stop := time.Now()
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txp.Saver.Write(trace.Event{
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Address: txp.Address(),
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DNSQuery: txp.maybeQueryBytes(query),
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DNSReply: txp.maybeResponseBytes(response),
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Duration: stop.Sub(start),
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Err: err,
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Name: "dns_round_trip_done",
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Proto: txp.Network(),
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Time: stop,
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})
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return response, err
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}
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func (txp SaverDNSTransport) maybeQueryBytes(query model.DNSQuery) []byte {
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data, _ := query.Bytes()
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return data
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}
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func (txp SaverDNSTransport) maybeResponseBytes(response model.DNSResponse) []byte {
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if response == nil {
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return nil
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}
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return response.Bytes()
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}
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var _ model.Resolver = SaverResolver{}
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var _ model.DNSTransport = SaverDNSTransport{}
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