1 files changed, 78 insertions, 0 deletions
diff --git a/services/docker/mail-server/relay/config.ts b/services/docker/mail-server/relay/config.ts
new file mode 100644
index 0000000..77c6e6e
--- /dev/null
+++ b/services/docker/mail-server/relay/config.ts
@@ -0,0 +1,78 @@
+import { createSingleton, transformProperties } from "./util.ts";
+
+export const APP_PREFIX = "crupest";
+export const APP_NAME = "mailserver";
+
+interface ConfigItemDef {
+  env: string;
+  description: string;
+  default?: string;
+  secret?: boolean;
+}
+
+export const CONFIG_DEFS = {
+  mailDomain: {
+    env: "MAIL_DOMAIN",
+    description: "the part after `@` of an address",
+  },
+  dataPath: {
+    env: "DATA_PATH",
+    description: "path to save app persistent data",
+  },
+  awsAccessKeyId: { env: "AWS_USER", description: "aws access key id" },
+  awsSecretAccessKey: {
+    env: "AWS_PASSWORD",
+    description: "aws secret access key",
+    secret: true,
+  },
+  awsMailBucket: {
+    env: "AWS_MAIL_BUCKET",
+    description: "aws s3 bucket saving raw mails",
+    secret: true,
+  },
+} as const satisfies Record<string, ConfigItemDef>;
+
+type ConfigDefs = typeof CONFIG_DEFS;
+type ConfigKey = keyof ConfigDefs;
+type ConfigMap = {
+  [K in ConfigKey]: ConfigItemDef & { value: string };
+};
+
+function getFullEnvKey(key: string): string {
+  return `${APP_PREFIX.toUpperCase()}_${APP_NAME.toUpperCase()}_${key}`;
+}
+
+function resolveAppConfigItem(def: ConfigItemDef): string {
+  const envKey = getFullEnvKey(def.env);
+  const value = Deno.env.get(envKey);
+  if (value != null) return value;
+  if (def.default != null) return def.default;
+  throw new Error(
+    `Required env ${envKey} (${def.description}) is not set.`,
+  );
+}
+
+export class Config {
+  #config = transformProperties(
+    CONFIG_DEFS,
+    (def) => ({ ...def, value: resolveAppConfigItem(def) }),
+  ) as ConfigMap;
+
+  get<K extends ConfigKey>(key: K): ConfigMap[K] {
+    return this.#config[key];
+  }
+
+  getValue(key: ConfigKey): string {
+    return this.get(key).value;
+  }
+
+  [Symbol.for("Deno.customInspect")]() {
+    return Object.entries(this.#config).map(([key, item]) =>
+      `${key} [env: ${getFullEnvKey(item.env)}]: ${
+        item.secret === true ? "***" : item.value
+      }`
+    ).join("\n");
+  }
+}
+
+export const [getConfig, setConfig] = createSingleton<Config>("Config");