WIP on async - test failure due to closed event loop

redis_om/model/render_tree.py

@@ -0,0 +1,75 @@
+"""
+This code adapted from the library "pptree," Copyright (c) 2017 Clément Michard
+and released under the MIT license: https://github.com/clemtoy/pptree
+"""
+import io
+
+
+def render_tree(
+    current_node,
+    nameattr="name",
+    left_child="left",
+    right_child="right",
+    indent="",
+    last="updown",
+    buffer=None,
+):
+    """Print a tree-like structure, `current_node`.
+
+    This is a mostly-direct-copy of the print_tree() function from the ppbtree
+    module of the pptree library, but instead of printing to standard out, we
+    write to a StringIO buffer, then use that buffer to accumulate written lines
+    during recursive calls to render_tree().
+    """
+    if buffer is None:
+        buffer = io.StringIO()
+    if hasattr(current_node, nameattr):
+        name = lambda node: getattr(node, nameattr)  # noqa: E731
+    else:
+        name = lambda node: str(node)  # noqa: E731
+
+    up = getattr(current_node, left_child, None)
+    down = getattr(current_node, right_child, None)
+
+    if up is not None:
+        next_last = "up"
+        next_indent = "{0}{1}{2}".format(
+            indent, " " if "up" in last else "|", " " * len(str(name(current_node)))
+        )
+        render_tree(
+            up, nameattr, left_child, right_child, next_indent, next_last, buffer
+        )
+
+    if last == "up":
+        start_shape = "┌"
+    elif last == "down":
+        start_shape = "└"
+    elif last == "updown":
+        start_shape = " "
+    else:
+        start_shape = "├"
+
+    if up is not None and down is not None:
+        end_shape = "┤"
+    elif up:
+        end_shape = "┘"
+    elif down:
+        end_shape = "┐"
+    else:
+        end_shape = ""
+
+    print(
+        "{0}{1}{2}{3}".format(indent, start_shape, name(current_node), end_shape),
+        file=buffer,
+    )
+
+    if down is not None:
+        next_last = "down"
+        next_indent = "{0}{1}{2}".format(
+            indent, " " if "down" in last else "|", " " * len(str(name(current_node)))
+        )
+        render_tree(
+            down, nameattr, left_child, right_child, next_indent, next_last, buffer
+        )
+
+    return f"\n{buffer.getvalue()}"