feat: phase 0 of networkx query reader, pagerank algo

partially implement: #28

ng_ai/engines.py

@@ -116,15 +116,35 @@ class NebulaEngine(BaseEngine):
     def __init__(self, config=None):
         self.type = "nebula"
         self.config = config
+
+        # let's make all nx related import here
+        import networkx as nx
+        import ng_nx
+        from ng_nx import NebulaReader as NxReader
+        from ng_nx import NxScanReader, NxWriter
+        from ng_nx.utils import NxConfig, result_to_df
+
+        self.nx = nx
+        self.ng_nx = ng_nx
+        self.nx_reader = NxReader
+        self.nx_writer = NxWriter
+        self.nx_scan_reader = NxScanReader
+        self._nx_config = NxConfig
+
+        self.result_to_df = result_to_df
+
+        self.nx_config = None
         self.parse_config()
 
     def __str__(self):
-        return f"NebulaEngine: {self.config}"
+        return (
+            f"NebulaEngine(NetworkX): {self.config}, "
+            f"nx version: {self.nx.__version__}, "
+            f"ng_nx version: {self.ng_nx.__version__}"
+        )
 
     def parse_config(self):
         """parse and validate config"""
         if self.config is None:
             return
-
-    def prepare(self):
-        pass
+        self.nx_config = self._nx_config(**self.config.__dict__)

ng_ai/nebula_algo.py

@@ -366,6 +366,7 @@ class NebulaGraphAlgorithm:
     def __init__(self, graph):
         self.graph = graph
         self.algorithms = []
+        self.engine = graph.engine
 
     def register_algo(self, func):
         self.algorithms.append(func.__name__)
@@ -384,14 +385,28 @@ def check_engine(self):
         For spark, we need to convert the NebulaGraphObject
             to NebulaDataFrameObject
         """
-        if self.graph.engine.type == "spark":
+        if self.engine.type == "spark":
             raise Exception(
                 "For NebulaGraphObject in spark engine,"
                 "Plz transform it to NebulaDataFrameObject to run algorithm",
                 "For example: df = nebula_graph.to_df; df.algo.pagerank()",
             )
+        if self.engine.type == "networkx":
+            return True
+        else:
+            raise Exception("Unsupported engine type")
 
     @algo
-    def pagerank(self, reset_prob=0.15, max_iter=10):
+    def pagerank(self, reset_prob=0.15, max_iter=10, **kwargs):
         self.check_engine()
-        pass
+        g = self.graph._graph
+        weight = kwargs.get("weight", None)
+        assert type(weight) in [str, type(None)], "weight must be str or None"
+        assert type(reset_prob) == float, "reset_prob must be float"
+        assert type(max_iter) == int, "max_iter must be int"
+        tol = kwargs.get("tol", 1e-06)
+        assert type(tol) == float, "tol must be float"
+
+        return self.engine.nx.pagerank(
+            g, alpha=1 - reset_prob, max_iter=max_iter, tol=tol, weight=weight
+        )

ng_ai/nebula_data.py

@@ -19,9 +19,16 @@ def get_engine(self):
 
     @property
     def algo(self):
-        from ng_ai.nebula_algo import NebulaAlgorithm as NebulaAlgorithmImpl
+        if self.engine.type == "spark":
+            print(
+                "NebulaGraphObject.algo is not supported in spark engine, "
+                "please use NebulaDataFrameObject.algo instead"
+            )
+            raise NotImplementedError
+        if self.engine.type == "nebula":
+            from ng_ai.nebula_algo import NebulaAlgorithm as NebulaAlgorithmImpl
 
-        return NebulaAlgorithmImpl(self)
+            return NebulaAlgorithmImpl(self)
 
     def get_nx_graph(self):
         if self.engine.type == "nebula":
@@ -81,9 +88,16 @@ def get_engine(self):
 
     @property
     def algo(self):
-        from ng_ai.nebula_algo import NebulaAlgorithm as NebulaAlgorithmImpl
+        if self.engine.type == "spark":
+            from ng_ai.nebula_algo import NebulaAlgorithm as NebulaAlgorithmImpl
 
-        return NebulaAlgorithmImpl(self)
+            return NebulaAlgorithmImpl(self)
+        else:
+            print(
+                "NebulaDataFrameObject.algo is not supported in nebula engine, "
+                "please use NebulaGraphObject.algo instead"
+            )
+            raise NotImplementedError
 
     def to_spark_df(self):
         if self.engine.type == "spark":
@@ -103,14 +117,11 @@ def to_pandas_df(self):
             raise NotImplementedError
 
     def to_networkx(self):
-        if self.engine.type == "nebula":
-            return nx.from_pandas_edgelist(self.data, "src", "dst")
-        else:
-            # for now the else case will be spark, to networkx is not supported
-            raise Exception(
-                "For NebulaDataFrameObject in spark engine,"
-                "convert to networkx graph is not supported",
-            )
+        # for now the else case will be spark, to networkx is not supported
+        raise Exception(
+            "For NebulaDataFrameObject in spark engine,"
+            "convert to networkx graph is not supported",
+        )
 
     def to_graphx(self):
         if self.engine.type == "spark":
@@ -128,4 +139,9 @@ def to_graph(self):
         return NebulaGraphObject(self)
 
     def show(self, *keywords, **kwargs):
-        return self.data.show(*keywords, **kwargs)
+        if self.engine.type == "spark":
+            self.data.show(*keywords, **kwargs)
+        elif self.engine.type == "nebula":
+            print(self.data)
+        else:
+            raise NotImplementedError

ng_ai/nebula_reader.py

@@ -5,6 +5,8 @@
 from ng_ai.config import NebulaGraphConfig
 from ng_ai.nebula_data import NebulaDataFrameObject
 
+DEFAULT_NEBULA_QUERY_LIMIT = 1000
+
 
 class NebulaReaderBase(object):
     def __init__(self, engine=None, config=None, **kwargs):
@@ -54,22 +56,52 @@ def __init__(self, config: NebulaGraphConfig, **kwargs):
         self.engine = NebulaEngine(config)
         self.raw_df = None
         self.df = None
+        self.reader = None
 
     def scan(self, **kwargs):
         # Implement the scan method specific to Nebula engine
         raise NotImplementedError
 
     def query(self, **kwargs):
-        # Implement the query method specific to Nebula engine
-        raise NotImplementedError
+        limit = kwargs.get("limit", DEFAULT_NEBULA_QUERY_LIMIT)
+        assert type(limit) == int, "limit should be an integer"
+        assert "space" in kwargs, "space is required"
+        space = kwargs["space"]
+        assert "edges" in kwargs, "edges is required"
+        edges = kwargs["edges"]
+        assert type(edges) == list, "edges should be a list"
+        length_of_edges = len(edges)
+        props = kwargs.get("props", [[]] * length_of_edges)
+        assert type(props) == list, "props should be a list"
+        assert (
+            len(props) == length_of_edges
+        ), "length of props should be equal to length of edges"
+        for prop in props:
+            assert type(prop) == list, "props should be a list of list"
+            for item in prop:
+                assert type(item) == str, "props should be a list of list of string"
+
+        self.reader = NebulaReader(
+            space=space,
+            edges=edges,
+            properties=props,
+            nebula_config=self.engine._nx_config,
+            limit=limit,
+        )
+
+        return self.reader
 
     def load(self, **kwargs):
         # Implement the load method specific to Nebula engine
         raise NotImplementedError
 
     def read(self, **kwargs):
-        # Implement the read method specific to Nebula engine
-        raise NotImplementedError
+        if self.reader is None:
+            raise Exception(
+                "reader is not initialized, please call query or scan first"
+            )
+        self._graph = self.reader.read()
+        return self._graph
 
     def show(self, **kwargs):
         # Implement the show method specific to Nebula engine