64 lines
2.3 KiB
Go
64 lines
2.3 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package tsweb
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import (
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"context"
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"net/http"
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"github.com/google/uuid"
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)
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// RequestID is an opaque identifier for a HTTP request, used to correlate
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// user-visible errors with backend server logs. The RequestID is typically
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// threaded through an HTTP Middleware (WithRequestID) and then can be extracted
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// by HTTP Handlers to include in their logs.
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//
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// RequestID is an opaque identifier for a HTTP request, used to correlate
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// user-visible errors with backend server logs. If present in the context, the
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// RequestID will be printed alongside the message text and logged in the
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// AccessLogRecord.
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//
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// A RequestID has the format "REQ-1{ID}", and the ID should be treated as an
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// opaque string. The current implementation uses a UUID.
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type RequestID string
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// RequestIDHeader is a custom HTTP header that the WithRequestID middleware
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// uses to determine whether to re-use a given request ID from the client
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// or generate a new one.
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const RequestIDHeader = "X-Tailscale-Request-Id"
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// SetRequestID is an HTTP middleware that injects a RequestID in the
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// *http.Request Context. The value of that request id is either retrieved from
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// the RequestIDHeader or a randomly generated one if not exists. Inner
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// handlers can retrieve this ID from the RequestIDFromContext function.
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func SetRequestID(h http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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id := r.Header.Get(RequestIDHeader)
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if id == "" {
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// REQ-1 indicates the version of the RequestID pattern. It is
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// currently arbitrary but allows for forward compatible
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// transitions if needed.
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id = "REQ-1" + uuid.NewString()
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}
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ctx := withRequestID(r.Context(), RequestID(id))
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r = r.WithContext(ctx)
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h.ServeHTTP(w, r)
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})
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}
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type requestIDKey struct{}
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// RequestIDFromContext retrieves the RequestID from context that can be set by
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// the SetRequestID function.
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func RequestIDFromContext(ctx context.Context) RequestID {
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val, _ := ctx.Value(requestIDKey{}).(RequestID)
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return val
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}
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// withRequestID sets the given request id value in the given context.
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func withRequestID(ctx context.Context, rid RequestID) context.Context {
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return context.WithValue(ctx, requestIDKey{}, rid)
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}
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