Add a file that just deals with handling modules and part data

1 files changed, 101 insertions, 0 deletions

diff --git a/cloudinit/handling.py b/cloudinit/handling.py
new file mode 100644
index 00000000..553abe4f
--- /dev/null
+++ b/cloudinit/handling.py
@@ -0,0 +1,101 @@
+import os
+
+from cloudinit import importer
+from cloudinit import log as logging
+from cloudinit.constants import (PER_INSTANCE, PER_ALWAYS)
+
+LOG = logging.getLogger(__name__)
+
+
+class InternalPartHandler:
+    freq = PER_INSTANCE
+    mtypes = []
+    handler_version = 1
+    handler = None
+
+    def __init__(self, handler, mtypes, frequency, version=2):
+        self.handler = handler
+        self.mtypes = mtypes
+        self.frequency = frequency
+        self.handler_version = version
+
+    def __repr__(self):
+        return("InternalPartHandler: [%s]" % self.mtypes)
+
+    def list_types(self):
+        return(self.mtypes)
+
+    def handle_part(self, data, ctype, filename, payload, frequency):
+        return(self.handler(data, ctype, filename, payload, frequency))
+
+
+def handler_register(mod, part_handlers, data, frequency=PER_INSTANCE):
+    if not hasattr(mod, "handler_version"):
+        setattr(mod, "handler_version", 1)
+
+    for mtype in mod.list_types():
+        part_handlers[mtype] = mod
+
+    handler_call_begin(mod, data, frequency)
+    return mod
+
+
+def handler_call_begin(mod, data, frequency):
+    handler_handle_part(mod, data, "__begin__", None, None, frequency)
+
+
+def handler_call_end(mod, data, frequency):
+    handler_handle_part(mod, data, "__end__", None, None, frequency)
+
+
+def handler_handle_part(mod, data, ctype, filename, payload, frequency):
+    # only add the handler if the module should run
+    modfreq = getattr(mod, "frequency", PER_INSTANCE)
+    if not (modfreq == PER_ALWAYS or
+            (frequency == PER_INSTANCE and modfreq == PER_INSTANCE)):
+        return
+    try:
+        if mod.handler_version == 1:
+            mod.handle_part(data, ctype, filename, payload)
+        else:
+            mod.handle_part(data, ctype, filename, payload, frequency)
+    except:
+        util.logexc(log)
+        traceback.print_exc(file=sys.stderr)
+
+
+def partwalker_handle_handler(pdata, _ctype, _filename, payload):
+    curcount = pdata['handlercount']
+    modname = 'part-handler-%03d' % curcount
+    frequency = pdata['frequency']
+
+    modfname = modname + ".py"
+    util.write_file(os.path.join(pdata['handlerdir'], modfname), payload, 0600)
+
+    try:
+        mod = importer.import_module(modname)
+        handler_register(mod, pdata['handlers'], pdata['data'], frequency)
+        pdata['handlercount'] = curcount + 1
+    except:
+        LOG.exception("Could not import module %s", modname)
+
+
+def partwalker_callback(pdata, ctype, filename, payload):
+    # data here is the part_handlers array and then the data to pass through
+    if ctype == "text/part-handler":
+        if 'handlercount' not in pdata:
+            pdata['handlercount'] = 0
+        partwalker_handle_handler(pdata, ctype, filename, payload)
+        return
+    if ctype not in pdata['handlers']:
+        if ctype == "text/x-not-multipart":
+            # Extract the first line or 24 bytes for displaying in the log
+            start = payload.split("\n", 1)[0][:24]
+            if start < payload:
+                details = "starting '%s...'" % start.encode("string-escape")
+            else:
+                details = repr(payload)
+            LOG.warning("Unhandled non-multipart userdata %s", details)
+        return
+    handler_handle_part(pdata['handlers'][ctype], pdata['data'],
+        ctype, filename, payload, pdata['frequency'])