From 3ff4d8b29750234c2f3170371acd2cdbd0d6fd3f Mon Sep 17 00:00:00 2001
From: shayan tabatabaee <shayan.ta69@gmail.com>
Date: Fri, 15 Nov 2019 11:56:19 +0330
Subject: [PATCH] fix: Add pause event to dateFile logger

---
 lib/appenders/dateFile.js |  8 +++++++-
 test/tap/pause-test.js    | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/lib/appenders/dateFile.js b/lib/appenders/dateFile.js
index d4578c2..5ab8a03 100644
--- a/lib/appenders/dateFile.js
+++ b/lib/appenders/dateFile.js
@@ -28,8 +28,14 @@ function appender(
     options
   );
 
+  logFile.on("drain", () => {
+    process.emit("log4js:pause", false);
+  });
+
   const app = function (logEvent) {
-    logFile.write(layout(logEvent, timezoneOffset) + eol, 'utf8');
+    if (!logFile.write(layout(logEvent, timezoneOffset) + eol, "utf8")) {
+      process.emit("log4js:pause", true);
+    }
   };
 
   app.shutdown = function (complete) {
diff --git a/test/tap/pause-test.js b/test/tap/pause-test.js
index f6db91c..e260040 100644
--- a/test/tap/pause-test.js
+++ b/test/tap/pause-test.js
@@ -33,5 +33,37 @@ tap.test("Drain event test", batch => {
     t.end();
   });
 
+
+  batch.test("Should emit pause event and resume when logging in a date file with high frequency", (t) => {
+    // Generate date file logger with 5MB of highWaterMark config
+    log4js.configure({
+      appenders: {
+        file: { type: "dateFile", filename: "logs/date-file-drain.log", highWaterMark: 5 * 1024 * 1024 }
+      },
+      categories: {
+        default: { appenders: ["file"], level: "debug" }
+      }
+    });
+
+    let onPause = false;
+    let onResume = false;
+
+    process.on("log4js:pause", value => {
+      if (value) {
+        onPause = true;
+      } else {
+        onResume = true;
+      }
+    });
+
+    const logger = log4js.getLogger();
+    while (onPause === false && onResume === false) {
+      if (onPause === false)
+        logger.info("This is a test for emitting drain event in date file logger");
+    }
+    t.end();
+
+  });
+
   batch.end();
 });