feat: configuration loader.

src/config-loader.ts

@@ -1,29 +1,68 @@
-import { AppConfig } from "./app-config.model";
-import { debug } from "console";
+import { AppConfig } from "./app-config.model.js";
 import { Etcd3 } from "etcd3";
 import { load } from "js-yaml";
 import { hostname } from "os";
-import { getEtcdInstance } from "./etcd-connection";
+import { getEtcdInstance } from "./etcd-connection.js";
+import { readFile } from "fs/promises";
+import debug from "debug";
 
-class ConfigLoader {
+export class ConfigLoader {
   private etcd: Etcd3;
 
   private readonly currHost = hostname();
   private readonly configKeyPrefix = "share/config";
+  private readonly logger = debug("fennec:config:loader");
 
-  constructor(config: AppConfig) {
+  constructor(config?: AppConfig) {
     this.etcd = getEtcdInstance(config);
   }
 
-  async loadConfig(configKey: string): Promise<any> {
-    const str = await this.etcd
-      .get(`${this.configKeyPrefix}/${this.currHost}/${configKey}`)
-      .string();
+  async loadConfig<T extends Object>(configKey?: string): Promise<any> {
+    const config = await (await import("find-up"))
+      .findUp(["config,yml", "config.yaml"])
+      .then((path) => {
+        if (path) {
+          return readFile(path, "utf8").then((str) => load(str));
+        } else {
+          return undefined;
+        }
+      });
 
-    if (!str) {
-      debug("config-loader", `No config found for ${configKey}`);
-      return null;
+    if (configKey === undefined) {
+      if (process.env.CONFIG_KEY) {
+        configKey = process.env.CONFIG_KEY;
+      } else if (process.env.config_key) {
+        configKey = process.env.config_key;
+      } else {
+        configKey = await (
+          await import("find-up")
+        )
+          .findUp("package.json")
+          .then((path) => {
+            if (path) {
+              return readFile(path, "utf8");
+            } else {
+              throw new Error(
+                "Fallback to using package name as configuration name"
+              );
+            }
+          })
+          .then((json) => JSON.parse(json)?.name as string);
+      }
     }
-    return load(str);
+    const etcdConfigKey = `${this.configKeyPrefix}/${this.currHost}/${configKey}`;
+    const str = await this.etcd.get(etcdConfigKey).string();
+
+    if (!str || !config) {
+      this.logger(
+        `Not define configuration.
+ - Put configuration in %s
+ - Provide configuration key in CONFIG_KEY environment variable
+ - Create "config.yml" file in current working directory (CWD)`,
+        etcdConfigKey
+      );
+      throw new Error(`Not define configuration.`);
+    }
+    return Object.assign(config, load(str)) as T;
   }
 }

src/etcd-connection.ts

@@ -1,14 +1,14 @@
 import { Etcd3 } from "etcd3";
-import { AppConfig } from "./app-config.model";
-function connectEtcd(config: AppConfig) {
+import { AppConfig } from "./app-config.model.js";
+function connectEtcd(config?: AppConfig) {
   return new Etcd3({
-    ...config.etcd,
+    ...(config?.etcd ?? { hosts: ["http://rpi:2379"] }),
   });
 }
 
 let instance: Etcd3;
 
-export function getEtcdInstance(config: AppConfig) {
+export function getEtcdInstance(config?: AppConfig) {
   if (!instance) {
     instance = connectEtcd(config);
   }

src/index.ts

@@ -1,4 +1,4 @@
-export * from "./app-config.model";
-export * from "./config-loader";
-export * from "./etcd-connection";
-export * from "./service-register";
+export * from "./app-config.model.js";
+export * from "./config-loader.js";
+export * from "./etcd-connection.js";
+export * from "./service-register.js";

src/service-register.ts

@@ -1,7 +1,7 @@
-import { AppConfig } from "./app-config.model";
+import { AppConfig } from "./app-config.model.js";
 import { Etcd3 } from "etcd3";
 import { hostname } from "os";
-import { getEtcdInstance } from "./etcd-connection";
+import { getEtcdInstance } from "./etcd-connection.js";
 import debug from "debug";
 
 export class ServiceRegister {
@@ -12,7 +12,7 @@ export class ServiceRegister {
 
   private readonly logger = debug("fennec:config:register");
 
-  constructor(config: AppConfig) {
+  constructor(config?: AppConfig) {
     this.etcd = getEtcdInstance(config);
   }