utils: add tiptorrent.py

Utility and wrapper functions related to the usage of tiptorrent.
To be used by the image restore command.

src/utils/tiptorrent.py

@@ -0,0 +1,90 @@
+import hashlib
+import logging
+import os
+import shlex
+import shutil
+import subprocess
+import urllib.request
+
+def _compute_md5(path, bs=2**20):
+    m = hashlib.md5()
+    with open(path, 'rb') as f:
+        while True:
+            buf = f.read(bs)
+            if not buf:
+                break
+            m.update(buf)
+    return m.hexdigest()
+
+
+def tip_fetch_csum(tip_addr, image_name):
+    """
+    """
+    url = f'http://{tip_addr}:9999/{image_name}.img.full.sum'
+    with urllib.request.urlopen(f'{url}') as resp:
+        r = resp.readline().rstrip().decode('utf-8')
+    return r
+
+
+def tip_write_csum(image_name):
+    """
+    TODO: Check for CACHE partition
+    """
+    image_path = f'/opt/opengnsys/cache/opt/opengnsys/images/{image_name}.img'
+
+    if not os.path.exists(image_path):
+        logging.error('Invalid image path')
+        raise ValueError('Invalid image path for tiptorrent checksum writing')
+
+    filename = image_path + ".full.sum"
+    csum = _compute_md5(image_path)
+    with open(filename, 'w') as f:
+        f.write(csum)
+
+    return csum
+
+
+def tip_check_csum(tip_addr, image_name):
+    """
+    """
+    image_path = f'/opt/opengnsys/cache/opt/opengnsys/images/{image_name}.img'
+    if not os.path.exists(image_path):
+        logging.error('Invalid image path')
+        raise ValueError('Invalid image path for tiptorrent image csum comparison')
+
+    cache_csum = _compute_md5(image_path)
+    remote_csum = tip_fetch_csum(tip_addr, image_name)
+    logging.debug(f'cache_csum: {cache_csum}')
+    logging.debug(f'remote_csum: {remote_csum}')
+    return cache_csum == remote_csum
+
+
+def tip_client_get(tip_addr, image_name):
+    """
+    tiptorrent-client wrapper
+
+    TODO: Check if CACHE partition is present
+    """
+    logging.info(f'Fetching image {image_name} from tiptorrent server at {tip_addr}')
+    cmd = f'tiptorrent-client {tip_addr} {image_name}.img'
+    logfile = open('/tmp/command.log', 'wb', 0)
+
+    try:
+        proc = subprocess.Popen(shlex.split(cmd),
+                                stdout=subprocess.PIPE,
+                                stderr=subprocess.PIPE,
+                                cwd='/opt/opengnsys/cache/opt/opengnsys/images/')
+        out, err = proc.communicate()
+    except:
+        logging.error('Exception when running software inventory subprocess')
+        raise ValueError('Error: Incorrect command value')
+    finally:
+        logging.debug(f'tip_client_get out: {out}')
+        logging.debug(f'tip_client_get err: {err}')
+        logfile.close()
+
+    if proc.returncode != 0:
+        logging.error(f'Error fetching image {image_name} via tiptorrent')
+    else:
+        logging.info('tiptorrent transfer completed, writing checksum')
+        tip_write_csum(image_name)