0007. Per-domain runtime configuration through a PHP front controller

• Status: Accepted (retroactive)
• Date: 2024-02-14

Context and Problem Statement

The API supports multi-domain (multi-tenant) deployments, where each domain has its own API URL, Sentry DSN and so on. With the approach in 0006 one container could serve only one configuration, because the values are written into index.html once at start.

Considered Options

Not recorded.

Decision Outcome

The runtime image switched from httpd to php:apache, and config/php/index.php became the entry point: it reads index.html, looks up the request’s HTTP_HOST and injects that domain’s variables before returning the page. First version (PR #1002): a mounted env_config.php with a $domains array. September 2024 (PR #1091): configuration comes from env vars instead — MULTI_DOMAINS=a.com,b.com plus variables prefixed with the upper-cased domain (dots/dashes → _, e.g. A_COM_REACT_APP_API_URL). Today every REACT_APP_* / VITE_APP_* value (per-domain or global) is written as window.<KEY>="…" at the <!-- inject env variables --> marker that config/config.ts emits, and REACT_APP_SENTRY_RELEASE is derived from the image’s /version file (January 2025, #1110/#1111).

Consequences

• Good: one container serves many tenants; config stays in env vars, in line with the API’s stateless config.
• Bad: a PHP runtime is now in the admin image only to template one HTML file.
• Bad: two injection mechanisms coexist (sed in entrypoint.sh and index.php).

Evidence

• a73e752e 2024-02-14 “Migratin to new version of Ant Design Pro… (#1002)” (PR body: “adding support for multidomain”) — admin/config/php/index.php, admin/Dockerfile (FROM php:apache), admin/config/php/env_config.php.
• 61e623a9 2024-09-27 “Update index.php (#1091)” — MULTI_DOMAINS env parsing.
• 9465a5b0 / 07e11a67 2025-01-02 “Feature/variables update (#1110/#1111)” — admin/config/php/index.php, admin/config/config.ts, admin/src/services/sentry.ts.