SurfSense/surfsense_web/docker-entrypoint.js

/**
 * Runtime environment variable substitution for Next.js Docker images.
 *
 * Next.js inlines NEXT_PUBLIC_* values at build time. The Docker image is built
 * with unique placeholder strings (e.g. __NEXT_PUBLIC_FASTAPI_BACKEND_URL__).
 * This script replaces those placeholders with real values from the container's
 * environment variables before the server starts.
 *
 * Runs once at container startup via docker-entrypoint.sh.
 */

const fs = require("fs");
const path = require("path");

const replacements = [
  [
    "__NEXT_PUBLIC_FASTAPI_BACKEND_URL__",
    process.env.NEXT_PUBLIC_FASTAPI_BACKEND_URL || "http://localhost:8000",
  ],
  [
    "__NEXT_PUBLIC_ELECTRIC_URL__",
    process.env.NEXT_PUBLIC_ELECTRIC_URL || "http://localhost:5133",
  ],
  [
    "__NEXT_PUBLIC_FASTAPI_BACKEND_AUTH_TYPE__",
    process.env.NEXT_PUBLIC_FASTAPI_BACKEND_AUTH_TYPE || "LOCAL",
  ],
  [
    "__NEXT_PUBLIC_ETL_SERVICE__",
    process.env.NEXT_PUBLIC_ETL_SERVICE || "DOCLING",
  ],
  [
    "__NEXT_PUBLIC_DEPLOYMENT_MODE__",
    process.env.NEXT_PUBLIC_DEPLOYMENT_MODE || "self-hosted",
  ],
  [
    "__NEXT_PUBLIC_ELECTRIC_AUTH_MODE__",
    process.env.NEXT_PUBLIC_ELECTRIC_AUTH_MODE || "insecure",
  ],
];

let filesProcessed = 0;
let filesModified = 0;

function walk(dir) {
  let entries;
  try {
    entries = fs.readdirSync(dir, { withFileTypes: true });
  } catch {
    return;
  }
  for (const entry of entries) {
    const full = path.join(dir, entry.name);
    if (entry.isDirectory()) {
      walk(full);
    } else if (entry.name.endsWith(".js")) {
      filesProcessed++;
      let content = fs.readFileSync(full, "utf8");
      let changed = false;
      for (const [placeholder, value] of replacements) {
        if (content.includes(placeholder)) {
          content = content.replaceAll(placeholder, value);
          changed = true;
        }
      }
      if (changed) {
        fs.writeFileSync(full, content);
        filesModified++;
      }
    }
  }
}

console.log("[entrypoint] Replacing environment variable placeholders...");
for (const [placeholder, value] of replacements) {
  console.log(`  ${placeholder} -> ${value}`);
}

walk(path.join(__dirname, ".next"));

const serverJs = path.join(__dirname, "server.js");
if (fs.existsSync(serverJs)) {
  let content = fs.readFileSync(serverJs, "utf8");
  let changed = false;
  filesProcessed++;
  for (const [placeholder, value] of replacements) {
    if (content.includes(placeholder)) {
      content = content.replaceAll(placeholder, value);
      changed = true;
    }
  }
  if (changed) {
    fs.writeFileSync(serverJs, content);
    filesModified++;
  }
}

console.log(
  `[entrypoint] Done. Scanned ${filesProcessed} files, modified ${filesModified}.`
);