Support custom $UNIXTIME directive in place of SOA serial

dzonegit.py

@@ -83,14 +83,26 @@ def get_file_contents(path, revision=None):
     return r.stdout
 
 
-def compile_zone(zonename, zonedata):
+def unixtime_directive(zonedata, unixtime=None):
+    """ Filter binary zone data. Replace $UNIXTIME with current unix time. """
+    if unixtime is None:
+        unixtime = int(time.time())
+    return re.sub(
+        br'\$UNIXTIME\b',
+        str(unixtime).encode("ascii"),
+        zonedata,
+        flags=re.IGNORECASE,
+    )
+
+
+def compile_zone(zonename, zonedata, unixtime=None):
     """ Compile the zone. Return tuple with results."""
     CompileResults = namedtuple(
         "CompileResults", "success, serial, zonehash, stderr",
     )
     r = subprocess.run(
         ["/usr/sbin/named-compilezone", "-o", "-", zonename, "/dev/stdin"],
-        input=zonedata,
+        input=unixtime_directive(zonedata, unixtime),
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
     )
@@ -193,13 +205,14 @@ def get_zone_name(path, zonedata):
 
 def check_updated_zones(against, revision=None, autoupdate_serial=False):
     """ Check whether all updated zone files compile. """
+    unixtime = int(time.time())
     for f in get_altered_files(against, "AMCR", revision):
         if not f.suffix == ".zone":
             continue
         print("Checking file {f}".format(f=f))
         zonedata = get_file_contents(f, revision)
         zname = get_zone_name(f, zonedata)
-        rnew = compile_zone(zname, zonedata)
+        rnew = compile_zone(zname, zonedata, unixtime)
         if not rnew.success:
             raise HookException(
                 "New zone version does not compile",
@@ -208,7 +221,7 @@ def check_updated_zones(against, revision=None, autoupdate_serial=False):
         try:
             zonedata = get_file_contents(f, against)
             zname = get_zone_name(f, zonedata)
-            rold = compile_zone(zname, zonedata)
+            rold = compile_zone(zname, zonedata, unixtime-1)
 
             if (rold.success and rold.zonehash != rnew.zonehash and not
                     is_serial_increased(rold.serial, rnew.serial)):

test_dzonegit.py

@@ -74,6 +74,26 @@ ns.example.com.      60 IN A 192.0.2.1
     assert r.zonehash == r2.zonehash
 
 
+def test_compile_unsmudged_zone():
+    testzone = b"""
+$ORIGIN example.com.
+@       60 IN SOA ns hostmaster (
+                                $UNIXTIME  ; serial
+                                3600       ; refresh (1 hour)
+                                900        ; retry (15 minutes)
+                                1814400    ; expire (3 weeks)
+                                60         ; minimum (1 minute)
+                                )
+        60 IN NS ns
+ns.example.com.      60 IN A 192.0.2.1
+"""
+    replaced = dzonegit.unixtime_directive(testzone)
+    assert b"$UNIXTIME" not in replaced
+    r = dzonegit.compile_zone("example.com", testzone, 123456)
+    assert r.success
+    assert r.serial == str(123456)
+
+
 def test_is_serial_increased():
     assert dzonegit.is_serial_increased(1234567890, "2018010100")
     assert dzonegit.is_serial_increased("2018010100", "4018010100")
@@ -228,6 +248,29 @@ $ORIGIN dummy.
         dzonegit.check_updated_zones("HEAD", autoupdate_serial=True)
     subprocess.call(["git", "add", "dummy.zone"])
     dzonegit.check_updated_zones(dzonegit.get_head())
+    git_dir.join("dummy.zone").write("""
+$ORIGIN dummy.
+@ 60 IN SOA ns hm $UNIXTIME 61 60 60 60
+  60 NS ns.example.org.
+""")
+    subprocess.call(["git", "add", "dummy.zone"])
+    dzonegit.check_updated_zones(dzonegit.get_head())
+    subprocess.call(["git", "commit", "-m", "dummy.zone with $UNIXTIME"])
+    git_dir.join("dummy.zone").write("""
+$ORIGIN dummy.
+@ 60 IN SOA ns hm 1 60 60 60 60
+  60 NS ns.example.org.
+""")
+    subprocess.call(["git", "add", "dummy.zone"])
+    with pytest.raises(ValueError):
+        dzonegit.check_updated_zones(dzonegit.get_head())
+    git_dir.join("dummy.zone").write("""
+$ORIGIN dummy.
+@ 60 IN SOA ns hm $UNIXTIME 60 60 60 60
+  60 NS ns.example.org.
+""")
+    subprocess.call(["git", "add", "dummy.zone"])
+    dzonegit.check_updated_zones(dzonegit.get_head())
     subprocess.call(["git", "commit", "-m", "final dummy.zone"])
     dzonegit.check_updated_zones("HEAD~", "HEAD")