Better implementation of 'latest'

- swi file timestamp is unreliable if clock is not set correctly
- extract build timestamp from manifest if available
- extract timestamp-ish string from 'version' file or from swi filename

packages/base/all/initrds/loader-initrd-files/src/bin/swiget

@@ -12,6 +12,9 @@ import subprocess
 import shutil
 import logging
 import tempfile
+import re
+import json
+import zipfile
 
 import onl.install.InstallUtils
 MountContext = onl.install.InstallUtils.MountContext
@@ -24,6 +27,98 @@ OnlMountManager = onl.mounts.OnlMountManager
 import onl.network
 HostInfo = onl.network.HostInfo
 
+SWI_TIMESTAMP_FMT = "%Y-%m-%d.%H:%M"
+
+SWI_TIMESTAMP_RE = re.compile(r"""
+  [0-9][0-9][0-9][0-9] [-] [0-9][0-9] [-] [0-9][0-9]
+  [.]
+  [0-9][0-9] [:] [0-9][0-9]
+""", re.VERBOSE)
+
+SWI_FNAME_TIMESTAMP_FMT = "%Y-%m-%d.%H%M"
+
+SWI_FNAME_TIMESTAMP_RE = re.compile(r"""
+  [0-9][0-9][0-9][0-9] [-] [0-9][0-9] [-] [0-9][0-9]
+  [.]
+  [0-9][0-9] [0-9][0-9]
+""", re.VERBOSE)
+
+def versionSortKey(vstr):
+
+    m = SWI_TIMESTAMP_RE.search(vstr)
+    if m is not None:
+        try:
+            return time.mktime(time.strptime(m.group(0), SWI_TIMESTAMP_FMT))
+        except ValueError:
+            pass
+
+    m = SWI_FNAME_TIMESTAMP_RE.search(vstr)
+    if m is not None:
+        try:
+            return time.mktime(time.strptime(m.group(0), SWI_FNAME_TIMESTAMP_FMT))
+        except ValueError:
+            pass
+
+    return None
+
+def manifestSortKey(mdata):
+
+    mdata = mdata.get('version', {})
+
+    vstr = mdata.get('BUILD_TIMESTAMP', None)
+    if vstr is not None:
+        try:
+            return time.mktime(time.strptime(vstr, SWI_TIMESTAMP_FMT))
+        except ValueError:
+            pass
+
+    vstr = mdata.get('FNAME_BUILD_TIMESTAMP', None)
+    if vstr is not None:
+        try:
+            return time.mktime(time.strptime(vstr, SWI_FNAME_TIMESTAMP_FMT))
+        except ValueError:
+            pass
+
+    return None
+
+def swiSortKey(swiPath):
+
+    try:
+        zf = zipfile.ZipFile(swiPath, "r")
+    except zipfile.BadZipFile:
+        return os.path.getmtime(swiPath)
+
+    try:
+        fd = zf.open("manifest.json", "r")
+    except KeyError:
+        fd = None
+    if fd is not None:
+        data = json.load(fd)
+        fd.close()
+    else:
+        data = {}
+    ts = manifestSortKey(data)
+    if ts is not None: return ts
+
+    try:
+        fd = zf.open("version", "r")
+    except KeyError:
+        fd = None
+    if fd is not None:
+        vstr = fd.read()
+        fd.close()
+    else:
+        vstr = ""
+    ts = versionSortKey(vstr)
+    if ts is not None: return ts
+
+    ts = versionSortKey(swiPath)
+    if ts is not None: return ts
+    # maybe the timestamp is embedded into the filename
+
+    # else, use the filesytem mtime, which is less reliable
+    return os.path.getmtime(swiPath)
+
 class Runner(onl.install.InstallUtils.SubprocessMixin):
 
     def __init__(self, log):
@@ -188,7 +283,7 @@ class Runner(onl.install.InstallUtils.SubprocessMixin):
         def latest(d):
             l = [x for x in os.listdir(d) if x.endswith('.swi')]
             l = [os.path.join(d, x) for x in l]
-            l.sort(key=os.path.getmtime)
+            l.sort(key=swiSortKey)
             return l[-1]
 
         pm = ProcMountsParser()