Swift and Pdb

1-swift-pdb.md

Using Pdb with Swift does not work because Swift redirects stdin (even in foreground mode). Here we describe how to get it work.

• apply attached patch on Swift source

• wherever you'd call pdb.set_strace() do it like this:

from swift.common.utils import stdio_restore import pdb stdio_restore.raw() pdb.set_trace()

or, for your convenience, as one liner ;) :

```python
from swift.common.utils import stdio_restore; import pdb; stdio_restore.raw(); pdb.set_trace()

• start Swift in foreground:

swift-init main start -n

2-swift-pdb.diff

diff --git a/swift/common/utils.py b/swift/common/utils.py
index 3c8c367..0291dac 100644
--- a/swift/common/utils.py
+++ b/swift/common/utils.py
@@ -1024,6 +1024,45 @@ def drop_privileges(user):
     os.chdir('/')   # in case you need to rmdir on where you started the daemon
     os.umask(0o22)  # ensure files are created with the correct privileges
 
+class _stdio_restore(object):
+
+    tty = os.environ.get("TTY")
+    if tty:
+      _fd = os.open(tty, os.O_RDWR)
+    else:
+      _fd = 2
+    if os.isatty(_fd):
+        enabled = True
+    else:
+        enabled = False
+    alt = [os.fdopen(_fd, 'r'), os.fdopen(_fd, 'w')]
+
+    def __init__(self):
+        self.store = [None, None]
+
+    def raw(self):
+        if not self.store[0]:
+            self.store[0], sys.stdin = sys.stdin, self.alt[0]
+            self.store[1], sys.stdout = sys.stdout, self.alt[1]
+            return True
+
+    def cook(self):
+        if self.store[0]:
+            self.store[0], sys.stdin = None, self.store[0]
+            self.store[1], sys.stdout = None, self.store[1]
+            return True
+
+    def switch(self):
+        self.raw() or self.cook()
+
+    __enter__ = raw
+
+    def __exit__(self, *a, **kw):
+        self.cook()
+
+if _stdio_restore.enabled:
+    stdio_restore = _stdio_restore()
+
 
 def capture_stdio(logger, **kwargs):
     """