waitfordb function and package config

.gitignore

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+/node_modules/

index.js

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+#! /usr/bin/env node
+'use strict'
+
+const path = require('path');
+
+const KNEXFILE_DEFAULT = 'knexfile';
+const RETRY_DEFAULT = 10;
+const DELAY_DEFAULT = 1;
+const TESTSQL = 'select 1+1';
+
+const sleep = (time) => new Promise((r) => setTimeout(r, time));
+
+const retry = async (fn, attempts, delaySeconds) => {
+    for (let i = 1; i <= attempts; i++) {
+        try {
+            await fn();
+            return true;
+        } catch (error) {
+            console.warn(`Attempt #${i}/${attempts} failed: ${error.message}`);
+        }
+        if (i < attempts) {
+            await sleep(1000 * delaySeconds);
+        }
+    }
+    return false;
+};
+
+const checkConnection = async (config) => {
+	const knex = require('knex')(config);
+	try {
+		await knex.raw(TESTSQL);
+	} finally {
+		await knex.destroy();
+	}
+}
+
+const checkKnexInstalled = () => {
+	try {
+		require('knex');
+	} catch (e) {
+		return false;
+	}
+	return true;
+}
+
+const waitfordb = async () => {
+	const config = require(path.join(process.cwd(), KNEXFILE_DEFAULT))
+	if (!checkKnexInstalled()) {
+		console.error("ERROR: Knex is not installed. Please run 'npm install knex'");
+		return process.exit(1);
+	}
+
+	const rc = await retry(() => checkConnection(config), RETRY_DEFAULT, DELAY_DEFAULT);
+	if (rc) {
+		console.info('Database connection successful');
+		return process.exit(0);
+	} else {
+		console.error('ERROR: There are no more attempts left, exiting...');
+		return process.exit(1);
+	}
+}
+
+
+waitfordb()
+

package.json

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+{
+  "name": "knex-waitfordb",
+  "version": "1.0.0",
+  "description": "Waiting knex database connection",
+  "license": "Apache-2.0",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/plesk/knex-waitfordb.git"
+  },
+  "bin": {
+    "knex-waitfordb": "index.js"
+  },
+  "dependencies": {}
+}

yarn.lock

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+# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
+# yarn lockfile v1
+
+