From 4d8df242b6599757b93eb6056e43fa786a830a57 Mon Sep 17 00:00:00 2001
From: Rick Nitsche <rick@phas.ubc.ca>
Date: Fri, 20 Nov 2020 18:21:51 -0800
Subject: [PATCH] feat(config): support endpoints grouped by dirs

---
 coco/config.py | 85 +++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 64 insertions(+), 21 deletions(-)

diff --git a/coco/config.py b/coco/config.py
index 2958f2b5..7a73d2c3 100644
--- a/coco/config.py
+++ b/coco/config.py
@@ -182,9 +182,14 @@ def load_config(path=None):
     if not any_exist:
         raise RuntimeError("No configuration files available.")
 
+    # Validate config
     _validate_and_resolve(config)
 
-    _load_endpoint_config(config)
+    # Load the endpoints
+    endpoint_tree = load_endpoint_tree(Path(config["endpoint_dir"]))
+
+    # We only record the endpoint list per se, not the whole top-level group
+    config["endpoints"] = endpoint_tree["endpoints"]
 
     return config
 
@@ -270,31 +275,69 @@ def _validate_and_resolve(config):
         raise RuntimeError("Config missing required values.")
 
 
-def _load_endpoint_config(config):
-    """Load the endpoint config.
+def load_endpoint(_file, group):
+    """Read an endpoint from disk.
 
-    The config is injected into the passed in config object.
+    Returns the parsed endpoint config entry.
     """
-    config["endpoints"] = []
+    # A file called "__meta.conf" (two underscores) can be used to set metadata
+    # about the containing endpoint group.
+    meta = _file.name == "__meta.conf"
+
+    # Only accept files ending in .conf as endpoint configs.
+    # Endpoint config files starting with an underscore (_) are disabled (except
+    # a __meta.conf file).
+    if meta or (_file.suffix == ".conf" and not _file.name.startswith("_")):
+        logger.debug(f"Loading endpoint config {_file}.")
 
-    endpoint_dir = Path(config["endpoint_dir"])
+        with _file.open("r") as fh:
+            try:
+                conf = yaml.safe_load(fh)
+            except yaml.YAMLError as exc:
+                logger.error(f"Failure reading YAML file {_file}: {exc}")
 
-    for endpoint_file in endpoint_dir.iterdir():
-        # Only accept files ending in .conf as endpoint configs.
-        # Endpoint config files starting with an underscore (_) are disabled.
-        if endpoint_file.suffix == ".conf" and not endpoint_file.name.startswith("_"):
-            logger.debug(f"Loading endpoint config {endpoint_file}.")
+        # Extra endpoint metadata
+        conf["meta"] = meta
+        conf["tree"] = False
 
-            # Remove .conf from the config file name to get the name of the endpoint
-            name = endpoint_file.stem
+        # Remove .conf from the config file name to get the name of the endpoint
+        conf["name"] = _file.stem
 
-            with endpoint_file.open("r") as fh:
-                try:
-                    conf = yaml.safe_load(fh)
-                except yaml.YAMLError as exc:
-                    logger.error(f"Failure reading YAML file {endpoint_file}: {exc}")
+        # TODO: validate the endpoint config in here
+        return conf
 
-            conf["name"] = name
 
-            # TODO: validate the endpoint config in here
-            config["endpoints"].append(conf)
+def load_endpoint_tree(path):
+    """Iterate over a directory `path` in the endpoint tree.
+
+    Returns an endpoint tree config for the directory,
+    containing the endpoints and subtrees found within.
+    """
+    tree = {
+        "name": path.name,
+        "tree": True,
+        "description": "Unremarkable endpoint tree",
+        "endpoints": [],
+    }
+    for dir_entry in path.iterdir():
+        if dir_entry.is_dir():
+            # Parse the subtree
+            subtree = load_endpoint_tree(dir_entry)
+
+            # The subtree is only added if it's not empty
+            if subtree["endpoints"]:
+                tree["endpoints"].append(subtree)
+        else:
+            endpoint = load_endpoint(dir_entry)
+
+            if endpoint["meta"]:
+                # If this was a _meta.conf file, merge (select) data into the
+                # tree config
+                for key in ["description"]:
+                    if key in endpoint:
+                        tree[key] = endpoint[key]
+            else:
+                # otherwise, append to this tree's endpoint list.
+                tree["endpoints"].append(load_endpoint(dir_entry))
+
+    return tree