docker: forward NEXT_PUBLIC_POSTHOG_TOKEN into the build stage#21
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Docker silently drops --build-arg values without a matching ARG declaration, so the PostHog token never reached next build and was never inlined into the client bundles — posthog.init() guard stayed undefined in prod.
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Summary
PostHog wasn't loading on prod (www.buildcanada.com). Root cause: the Dockerfile's builder stage never declared
ARG NEXT_PUBLIC_POSTHOG_TOKEN, and Docker silently drops--build-argvalues without a matchingARG. The token therefore never reachednext build, so it was never inlined into the client bundles — theposthog.init()guard ininstrumentation-client.tsevaluatedundefinedin the browser and init never ran.Verified against the deployed bundles: the compiled init is still a runtime
process.envlookup (empty polyfill in the browser) and nophc_token string exists anywhere in the chunks, whileNEXT_PUBLIC_SITE_URL(which does have an ARG) took effect on the same rebuild.Changes
ARG NEXT_PUBLIC_POSTHOG_TOKEN+ENVforwarding in the builder stage so the deploy's existing--build-argactually reachesnext build.Testing
After this merges and prod rebuilds (with
--build-arg NEXT_PUBLIC_POSTHOG_TOKEN=phc_...passed):phc_token should appear inlined in the instrumentation chunkposthog.__loaded === truein the prod console, events visible in PostHog