69fd0c5119
This diff modifies the construction of a dialer to allow one to insert custom dialer wrappers into the dialers chain. The point of the chain in which we allow custom wrappers is the optimal one for connect, read, and write measurements. This new design is better than the previous netx design since we don't need to construct the whole chain manually now. The work in this diff is part of the effort to make engine/netx just a tiny wrapper around netxlite. See https://github.com/ooni/probe/issues/2121.
78 lines
2.5 KiB
Go
78 lines
2.5 KiB
Go
// Package dialer allows you to create a net.Dialer-compatible
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// DialContext-enabled dialer with error wrapping, optional logging,
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// optional network-events saving, and optional proxying.
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package dialer
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import (
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"net/url"
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"github.com/ooni/probe-cli/v3/internal/bytecounter"
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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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"github.com/ooni/probe-cli/v3/internal/netxlite"
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)
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// Config contains the settings for New.
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type Config struct {
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// ContextByteCounting optionally configures context-based
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// byte counting. By default we don't do that.
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//
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// Use WithExperimentByteCounter and WithSessionByteCounter
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// to assign byte counters to a context. The code will use
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// corresponding, private functions to access the configured
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// byte counters and will notify them about I/O events.
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//
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// Bug
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//
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// This implementation cannot properly account for the bytes that are sent by
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// persistent connections, because they stick to the counters set when the
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// connection was established. This typically means we miss the bytes sent and
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// received when submitting a measurement. Such bytes are specifically not
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// seen by the experiment specific byte counter.
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//
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// For this reason, this implementation may be heavily changed/removed.
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ContextByteCounting bool
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// DialSaver is the optional saver for dialing events. If not
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// set, we will not save any dialing event.
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DialSaver *trace.Saver
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// Logger is the optional logger. If not set, there
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// will be no logging from the new dialer.
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Logger model.DebugLogger
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// ProxyURL is the optional proxy URL.
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ProxyURL *url.URL
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// ReadWriteSaver is like DialSaver but for I/O events.
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ReadWriteSaver *trace.Saver
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}
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// New creates a new Dialer from the specified config and resolver.
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func New(config *Config, resolver model.Resolver) model.Dialer {
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var logger model.DebugLogger = model.DiscardLogger
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if config.Logger != nil {
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logger = config.Logger
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}
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modifiers := []netxlite.DialerWrapper{
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func(dialer model.Dialer) model.Dialer {
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if config.DialSaver != nil {
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dialer = &saverDialer{Dialer: dialer, Saver: config.DialSaver}
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}
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return dialer
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},
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func(dialer model.Dialer) model.Dialer {
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if config.ReadWriteSaver != nil {
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dialer = &saverConnDialer{Dialer: dialer, Saver: config.ReadWriteSaver}
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}
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return dialer
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},
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}
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d := netxlite.NewDialerWithResolver(logger, resolver, modifiers...)
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d = &netxlite.MaybeProxyDialer{ProxyURL: config.ProxyURL, Dialer: d}
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if config.ContextByteCounting {
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d = &bytecounter.ContextAwareDialer{Dialer: d}
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}
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return d
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}
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