remote: T5650: Resize-aware progressbar implementation

1 files changed, 70 insertions, 0 deletions

diff --git a/python/vyos/progressbar.py b/python/vyos/progressbar.py
new file mode 100644
index 000000000..1793c445b
--- /dev/null
+++ b/python/vyos/progressbar.py
@@ -0,0 +1,70 @@
+# Copyright 2023 VyOS maintainers and contributors <maintainers@vyos.io>
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library.  If not, see <http://www.gnu.org/licenses/>.
+
+import math
+import os
+import signal
+import subprocess
+import sys
+
+from vyos.utils.io import print_error
+
+class Progressbar:
+    def __init__(self, step=None):
+        self.total = 0.0
+        self.step = step
+    def __enter__(self):
+        # Recalculate terminal width with every window resize.
+        signal.signal(signal.SIGWINCH, lambda signum, frame: self._update_cols())
+        # Disable line wrapping to prevent the staircase effect.
+        subprocess.run(['tput', 'rmam'], check=False)
+        self._update_cols()
+        # Print an empty progressbar with entry.
+        self.progress(0, 1)
+        return self
+    def __exit__(self, exc_type, kexc_val, exc_tb):
+        # Revert to the default SIGWINCH handler (ie nothing).
+        signal.signal(signal.SIGWINCH, signal.SIG_DFL)
+        # Reenable line wrapping.
+        subprocess.run(['tput', 'smam'], check=False)
+    def _update_cols(self):
+        # `os.get_terminal_size()' is fast enough for our purposes.
+        self.col = max(os.get_terminal_size().columns - 15, 20)
+    def increment(self):
+        """
+        Stateful progressbar taking the step fraction at init and no input at
+        callback (for FTP)
+        """
+        if self.step:
+            if self.total < 1.0:
+                self.total += self.step
+            if self.total >= 1.0:
+                self.total = 1.0
+                # Ignore superfluous calls caused by fuzzy FTP size calculations.
+                self.step = None
+            self.progress(self.total, 1.0)
+    def progress(self, done, total):
+        """
+        Stateless progressbar taking no input at init and current progress with
+        final size at callback (for SSH)
+        """
+        if done <= total:
+            length = math.ceil(self.col * done / total)
+            percentage = str(math.ceil(100 * done / total)).rjust(3)
+            # Carriage return at the end will make sure the line will get overwritten.
+            print_error(f'[{length * "#"}{(self.col - length) * "_"}] {percentage}%', end='\r')
+        # Print a newline to make sure the full progressbar doesn't get overwritten by the next line.
+        if done == total:
+            print_error()