Coffee journaling on ATProto (alpha)
alpha.arabica.social
coffee
feat: improved multi-request otel tracing
authored by
Patrick Dewey
and committed by
tangled.org
3ed1099c
75e29b74
+38
+26
internal/web/bff/tracing.go
+26
internal/web/bff/tracing.go
···
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package bff
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import (
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"context"
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"fmt"
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"go.opentelemetry.io/otel/trace"
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)
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// Traceparent returns the W3C traceparent header value for the current span,
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// or an empty string if no active trace exists. This is intended to be called
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// from templ templates so that client-side requests (HTMX) can propagate the
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// trace context back to the server.
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func Traceparent(ctx context.Context) string {
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sc := trace.SpanFromContext(ctx).SpanContext()
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if !sc.HasTraceID() || !sc.HasSpanID() {
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return ""
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}
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flags := "00"
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if sc.IsSampled() {
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flags = "01"
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}
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return fmt.Sprintf("00-%s-%s-%s", sc.TraceID(), sc.SpanID(), flags)
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}
+12
internal/web/components/layout.templ
+12
internal/web/components/layout.templ
···
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// Increase history cache size to prevent cache misses
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htmx.config.historyCacheSize = 20;
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// Propagate W3C traceparent to HTMX requests so sub-requests
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// (e.g. /api/feed, /api/popular-recipes) share the page's trace
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var tp = document.querySelector('meta[name="traceparent"]');
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if (tp) {
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document.body.addEventListener('htmx:configRequest', function(evt) {
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evt.detail.headers['traceparent'] = tp.content;
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});
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}
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// Show session-expired modal on 401 responses
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document.body.addEventListener('htmx:afterRequest', function(evt) {
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if (evt.detail.xhr && evt.detail.xhr.status === 401) {
···
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<script src="/static/js/data-cache.js?v=0.3.0"></script>
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<script src="/static/js/sw-register.js?v=0.2.0"></script>
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</head>
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if tp := bff.Traceparent(ctx); tp != "" {
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<meta name="traceparent" content={ tp }/>
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}
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<body
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class="min-h-full flex flex-col"
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style="background-color: var(--page-bg); color: var(--page-text);"