upgrade-zulip: Archive release tarballs at /home/zulip/archives.

A common issue when doing a Zulip upgrade is trying to pass
upgrade-zulip a tarball path under /root, which doesn't work because
the Zulip user doesn't have permission to read the tarball.  We
could fix this by just unpacking the tarballs as root, but it seemed
like a nicer approach would be to archive the release tarballs
somewhere readable by the Zulip user (/home/zulip/archives) and unpack
them from there.

Fixes #208.

README.prod.md

@@ -343,14 +343,10 @@ upgrade.
 
 * To upgrade to a new version of the zulip server, download the
   appropriate release tarball from
-  https://www.zulip.com/dist/releases/ to a path readable by the zulip
-  user (e.g. /home/zulip), and then run as root:
+  https://www.zulip.com/dist/releases/ and then run as root:
   ```
   /home/zulip/deployments/current/scripts/upgrade-zulip zulip-server-VERSION.tar.gz
   ```
-  Be sure to download to a path readable by the Zulip user (see
-  https://github.com/zulip/zulip/issues/208 for details on this
-  issue) but then run the upgrade as root.
 
   The upgrade process will shut down the service, run `apt-get
   upgrade`, a puppet apply, and any database migrations, and then

scripts/lib/upgrade-zulip

@@ -1,16 +1,18 @@
 #!/usr/bin/env python2.7
 import os
+import shutil
 import sys
 import subprocess
 import logging
 import shutil
 import time
 
+TARBALL_ARCHIVE_PATH="/home/zulip/archives"
 os.environ["PYTHONUNBUFFERED"] = "y"
 
 sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..'))
 from zulip_tools import DEPLOYMENTS_DIR, LOCK_DIR, FAIL, WARNING, ENDC, \
-    su_to_zulip
+    mkdir_p, su_to_zulip
 
 logging.basicConfig(format="%(asctime)s upgrade-zulip: %(message)s",
                     level=logging.INFO)
@@ -46,9 +48,20 @@ if not got_lock:
     sys.exit(1)
 
 try:
+    # Copy the release tarball to an archival path that's readable by
+    # the Zulip user, and then unpack it from that directory, so that
+    # we can unpack using the Zulip user even if the original path was
+    # not readable by the Zulip user.
+    logging.info("Archiving the tarball under %s" % (TARBALL_ARCHIVE_PATH,))
+    mkdir_p(TARBALL_ARCHIVE_PATH)
+    archived_tarball_path = os.path.join(TARBALL_ARCHIVE_PATH, os.path.basename(tarball_path))
+    shutil.copy(tarball_path, archived_tarball_path)
+    subprocess.check_output(["chown", "-R", "zulip:zulip", TARBALL_ARCHIVE_PATH])
+
     logging.info("Unpacking the tarball")
     unpack_zulip = os.path.realpath(os.path.join(os.path.dirname(__file__), 'unpack-zulip'))
-    deploy_path = subprocess.check_output([unpack_zulip, tarball_path], preexec_fn=su_to_zulip)
+    deploy_path = subprocess.check_output([unpack_zulip, archived_tarball_path],
+                                          preexec_fn=su_to_zulip)
 
     # Chdir to deploy_path and then run upgrade-zulip-stage-2 from the
     # new version of Zulip (having the upgrade logic run from the new

zulip_tools.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python2.7
 from __future__ import print_function
+import errno
 import os
 import sys
 import datetime
@@ -29,3 +30,13 @@ if __name__ == '__main__':
     cmd = sys.argv[1]
     if cmd == 'make_deploy_path':
         print(make_deploy_path())
+
+def mkdir_p(path):
+    # Python doesn't have an analog to `mkdir -p` < Python 3.2.
+    try:
+        os.makedirs(path)
+    except OSError, e:
+        if e.errno == errno.EEXIST and os.path.isdir(path):
+            pass
+        else:
+            raise