image pull progress bar (#33)

Add a progress bar that shows uenv image pull progress

Very useful for large images, which take a long enough to download.

install

@@ -172,6 +172,7 @@ run install -v -m644 -D -t "${destdir}/${lib_path}" ${script_path}/lib/datastore
 run install -v -m644 -D -t "${destdir}/${lib_path}" ${script_path}/lib/jfrog.py
 run install -v -m644 -D -t "${destdir}/${lib_path}" ${script_path}/lib/names.py
 run install -v -m644 -D -t "${destdir}/${lib_path}" ${script_path}/lib/oras.py
+run install -v -m644 -D -t "${destdir}/${lib_path}" ${script_path}/lib/progress.py
 run install -v -m644 -D -t "${destdir}/${lib_path}" ${script_path}/lib/record.py
 run install -v -m644 -D -t "${destdir}/${lib_path}" ${script_path}/lib/terminal.py
 

lib/oras.py

@@ -25,21 +25,33 @@ def find_oras() -> str:
     return oras_file
 
 
-def run_command(args):
+def run_command(args, detach=False):
     try:
         command = [find_oras()] + args
 
         terminal.info(f"calling oras: {' '.join(command)}")
-        result = subprocess.run(
-            command,
-            stdout=subprocess.PIPE,  # Capture standard output
-            stderr=subprocess.PIPE,  # Capture standard error
-            check=True,  # Raise exception if command fails
-            encoding='utf-8'  # Decode output from bytes to string
-        )
-
-        # Print standard output
-        terminal.info("Output:\n{result.stdout}")
+        if detach:
+            process = subprocess.Popen(
+                command,
+                stdout=subprocess.PIPE,  # Capture standard output
+                stderr=subprocess.PIPE,  # Capture standard error
+                encoding='utf-8'  # Decode output from bytes to string
+            )
+            return process
+
+        else:
+            result = subprocess.run(
+                command,
+                stdout=subprocess.PIPE,  # Capture standard output
+                stderr=subprocess.PIPE,  # Capture standard error
+                check=True,  # Raise exception if command fails
+                encoding='utf-8'  # Decode output from bytes to string
+            )
+
+            # Print standard output
+            terminal.info("Output:\n{result.stdout}")
+
+            return None
 
     except subprocess.CalledProcessError as e:
         # Print error message along with captured standard error

lib/progress.py

@@ -0,0 +1,35 @@
+import math
+import sys
+from terminal import colorize
+
+def progress_bar(progress: float, width=25, msg="", stream=sys.stdout):
+    progress = min(1., max(0., progress))
+
+    fancy_bar = True
+    filled_slots = math.floor(width * progress)
+    lsep = colorize("[", "yellow")
+    rsep = colorize("]", "yellow")
+    if filled_slots==width:
+        if fancy_bar:
+            bar = colorize("≡"*width, "green")
+        else:
+            bar = colorize("="*width, "green")
+    else:
+        part_slot = (width * progress) - filled_slots
+        empty_slots = width - (filled_slots+1)
+        if fancy_bar:
+            part_width = math.floor(part_slot * 3)
+            part_char = [" ", "-", "="][part_width]
+            bar = colorize("≡"*filled_slots + part_char, "green") + " "*empty_slots
+        else:
+            part_width = math.floor(part_slot * 2)
+            part_char = [" ", "-"][part_width]
+            bar = colorize("="*filled_slots + part_char, "green") + " "*empty_slots
+
+    bar = lsep + bar + rsep
+
+    pc_str = f"{int(100*progress):3d}%"
+
+    # Use '\r' to return to the start of the line
+    stream.write('\r  ' + bar + " " + pc_str + " " + msg)
+    stream.flush()

uenv-image

@@ -12,6 +12,7 @@ import pathlib
 import re
 import sys
 import textwrap
+import time
 
 prefix = pathlib.Path(__file__).parent.resolve()
 libpath = prefix / 'lib'
@@ -22,6 +23,7 @@ import datastore
 import jfrog
 import names
 import oras
+import progress
 import record
 import terminal
 from terminal import colorize
@@ -444,7 +446,36 @@ if __name__ == "__main__":
             if cache.database.get_record(t.sha256).is_empty:
                 terminal.stdout(f"downloading image {t.sha256} {image_size_string(t.size)}")
                 # download the image using oras
-                oras.run_command(["pull", "-o", image_path, source_address])
+                try:
+                    # run the oras command in a separate process so that this process can
+                    # draw a progress bar.
+                    proc = oras.run_command(["pull", "-o", image_path, source_address], detach=True)
+                    total_mb = t.size/(1024*1024)
+                    while proc.poll() is None:
+                        time.sleep(0.25)
+                        sqfs_path = image_path + "/store.squashfs"
+                        if os.path.exists(sqfs_path):
+                            current_size = os.path.getsize(sqfs_path)
+                            current_mb = current_size / (1024*1024)
+                            p = current_mb/total_mb
+                            msg = f"{int(current_mb)}/{int(total_mb)} MB"
+                            progress.progress_bar(p, width=50, msg=msg)
+                    # draw a final complete progress bar
+                    progress.progress_bar(1.0, width=50, msg=f"{int(total_mb)}/{int(total_mb)} MB")
+                except KeyboardInterrupt:
+                    proc.terminate()
+                    terminal.stdout("")
+                    terminal.error(f"image pull cancelled by user.")
+                except Exception as e:
+                    proc.terminate()
+                    terminal.stdout("")
+                    terminal.error(f"image pull failed: {str(e)}")
+                sys.stdout.write("\n")
+                sys.stdout.flush()
+                if proc.returncode == 0:
+                    terminal.info(f"oras download completed successfully\n{proc.stdout}")
+                else:
+                    terminal.error(f"oras download failed {proc.stderr}")
             else:
                 terminal.stdout(f"image {t.sha256} is already available locally")
             # update all the tags associated with the image.
@@ -453,7 +484,7 @@ if __name__ == "__main__":
                 terminal.stdout(f"updating local reference {r.name}/{r.version}:{r.tag}")
                 cache.add_record(r)
 
-            terminal.stdout(f"image available at {image_path}/store.squashfs")
+            terminal.stdout(f"uenv {t.name}/{t.version}:{t.tag} downloaded")
 
         sys.exit(0)