def parse_action_node(self, action_node: ET.Element):
"""
Action nodes are the mechanism by which a workflow triggers the
execution of a computation/processing task.
Action nodes are required to have an action-choice (map-reduce, etc.),
ok, and error node in the xml.
"""
# The 0th element of the node is the actual action tag.
# In the form of 'action'
action_operation_node = action_node[0]
action_name = action_operation_node.tag
mapper: BaseMapper
if action_name not in self.action_map:
action_name = "unknown"
mapper = DummyMapper(
oozie_node=action_operation_node,
name=action_node.attrib["name"],
dag_name=self.workflow.dag_name,
props=self.props,
)
else:
map_class = self.action_map[action_name]
mapper = map_class(
oozie_node=action_operation_node,
name=action_node.attrib["name"],
props=self.props,
dag_name=self.workflow.dag_name,
action_mapper=self.action_map,
renderer=self.renderer,
input_directory_path=self.workflow.input_directory_path,
output_directory_path=self.workflow.output_directory_path,
jar_files=self.workflow.jar_files,
transformers=self.transformers,
)
oozie_action_node = OozieActionNode(mapper)
ok_node = action_node.find("ok")
if ok_node is None:
raise Exception(f"Missing ok node in {action_node}")
oozie_action_node.downstream_names.append(ok_node.attrib["to"])
error_node = action_node.find("error")
if error_node is None:
raise Exception(f"Missing error node in {action_node}")
oozie_action_node.error_downstream_name = error_node.attrib["to"]
mapper.on_parse_node()
logging.info(
f"Parsed {mapper.name} as Action Node of type {action_name}.")
self.workflow.nodes[mapper.name] = oozie_action_node
def parse_join_node(self, join_node):
"""
Join nodes wait for the corresponding beginning fork node paths to
finish. As the parser we are assuming the Oozie workflow follows the
schema perfectly.
"""
mapper = DummyMapper(oozie_node=join_node,
name=join_node.attrib["name"],
dag_name=self.workflow.dag_name)
p_node = ParsedActionNode(mapper)
p_node.add_downstream_node_name(join_node.attrib["to"])
mapper.on_parse_node()
logging.info(f"Parsed {mapper.name} as Join Node.")
self.workflow.nodes[join_node.attrib["name"]] = p_node
def parse_fork_node(self, root, fork_node):
"""
Fork nodes need to be dummy operators with multiple parallel downstream
tasks.
This parses the fork node, the action nodes that it references and then
the join node at the end.
This will only parse well-formed xml-adhering workflows where all paths
end at the join node.
"""
fork_name = fork_node.attrib["name"]
mapper = DummyMapper(oozie_node=fork_node,
name=fork_name,
dag_name=self.workflow.dag_name)
p_node = ParsedActionNode(mapper)
mapper.on_parse_node()
logging.info(f"Parsed {mapper.name} as Fork Node.")
paths = []
for node in fork_node:
if "path" in node.tag:
# Parse all the downstream tasks that can run in parallel.
curr_name = node.attrib["start"]
paths.append(xml_utils.find_node_by_name(root, curr_name))
self.workflow.nodes[fork_name] = p_node
for path in paths:
p_node.add_downstream_node_name(path.attrib["name"])
logging.info(
f"Added {mapper.name}'s downstream: {path.attrib['name']}")
# Theoretically these will all be action nodes, however I don't
# think that is guaranteed.
# The end of the execution path has not been reached
self.parse_node(root, path)
if path.attrib["name"] not in self.workflow.nodes:
root.remove(path)