Use SOURCE_DATE_EPOCH for metadata timestamps

This include .buildinfo, .treeinfo and .discinfo.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
(cherry picked from commit 876ec52215)

src/pylorax/buildstamp.py

@@ -23,6 +23,7 @@ import logging
 logger = logging.getLogger("pylorax.buildstamp")
 
 import datetime
+import os
 
 
 class BuildStamp(object):
@@ -34,6 +35,10 @@ class BuildStamp(object):
         self.isfinal = isfinal
         self.variant = variant
 
+        if 'SOURCE_DATE_EPOCH' in os.environ:
+            now = datetime.datetime.utcfromtimestamp(
+                int(os.environ['SOURCE_DATE_EPOCH']))
+        else:
             now = datetime.datetime.now()
         now = now.strftime("%Y%m%d%H%M")
         self.uuid = "{0}.{1}".format(now, buildarch)

src/pylorax/discinfo.py

@@ -22,6 +22,7 @@
 import logging
 logger = logging.getLogger("pylorax.discinfo")
 
+import os
 import time
 
 
@@ -32,8 +33,13 @@ class DiscInfo(object):
         self.basearch = basearch
 
     def write(self, outfile):
+        if 'SOURCE_DATE_EPOCH' in os.environ:
+            timestamp = int(os.environ['SOURCE_DATE_EPOCH'])
+        else:
+            timestamp = time.time()
+
         logger.info("writing .discinfo file")
         with open(outfile, "w") as fobj:
-            fobj.write("{0:f}\n".format(time.time()))
+            fobj.write("{0:f}\n".format(timestamp))
             fobj.write("{0.release}\n".format(self))
             fobj.write("{0.basearch}\n".format(self))

src/pylorax/treeinfo.py

@@ -23,6 +23,7 @@ import logging
 logger = logging.getLogger("pylorax.treeinfo")
 
 import configparser
+import os
 import time
 
 
@@ -33,8 +34,13 @@ class TreeInfo(object):
 
         self.c = configparser.ConfigParser()
 
+        if 'SOURCE_DATE_EPOCH' in os.environ:
+            timestamp = os.environ['SOURCE_DATE_EPOCH']
+        else:
+            timestamp = str(time.time())
+
         section = "general"
-        data = {"timestamp": str(time.time()),
+        data = {"timestamp": timestamp,
                 "family": product,
                 "version": version,
                 "name": "%s-%s" % (product, version),