From 359e40363933c5013e260132ad110acbcca395a8 Mon Sep 17 00:00:00 2001
From: Andrey Goncharov <aigoncharov@fb.com>
Date: Thu, 9 Dec 2021 09:47:01 -0800
Subject: [PATCH] Disable idb stdout buffering for logs

Summary:
Changelog: Disable idb stdout buffering for logs. Show logs on iOS devices without buffering.

Currently, idb buffers log output if it's redirected to a non-TTY. It is the default behavior for Python (read more about it [here](https://eklitzke.org/stdout-buffering)).
It leads to users seeing logs only in large chunks because the size of the buffer is substantial.
Setting PYTHONUNBUFFERED to a non-empty string disables Python output buffering.

Reviewed By: lblasa

Differential Revision: D32984711

fbshipit-source-id: 3e0a889b6b60b6d266f4a0c1894db937868c7433
---
 .../src/devices/ios/IOSBridge.tsx                    |  6 +++++-
 .../src/devices/ios/__tests__/IOSBridge.node.tsx     | 12 ++++++++++--
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/desktop/flipper-server-core/src/devices/ios/IOSBridge.tsx b/desktop/flipper-server-core/src/devices/ios/IOSBridge.tsx
index 1cc0c80a3..df230a792 100644
--- a/desktop/flipper-server-core/src/devices/ios/IOSBridge.tsx
+++ b/desktop/flipper-server-core/src/devices/ios/IOSBridge.tsx
@@ -70,7 +70,11 @@ export function idbStartLogListener(
   return child_process.spawn(
     idbPath,
     ['log', '--udid', udid, '--', ...getLogExtraArgs(deviceType)],
-    {},
+    {
+      env: {
+        PYTHONUNBUFFERED: '1',
+      },
+    },
   );
 }
 
diff --git a/desktop/flipper-server-core/src/devices/ios/__tests__/IOSBridge.node.tsx b/desktop/flipper-server-core/src/devices/ios/__tests__/IOSBridge.node.tsx
index 10ee78e74..8239a0eea 100644
--- a/desktop/flipper-server-core/src/devices/ios/__tests__/IOSBridge.node.tsx
+++ b/desktop/flipper-server-core/src/devices/ios/__tests__/IOSBridge.node.tsx
@@ -67,7 +67,11 @@ test('uses idb when present and xcode detected', async () => {
       '--debug',
       '--info',
     ],
-    {},
+    {
+      env: {
+        PYTHONUNBUFFERED: '1',
+      },
+    },
   );
 });
 
@@ -85,7 +89,11 @@ test('uses idb when present and xcode detected and physical device connected', a
       '--',
       // no further args; not supported by idb atm
     ],
-    {},
+    {
+      env: {
+        PYTHONUNBUFFERED: '1',
+      },
+    },
   );
 });