From 97ae802247062676bb2bd9469237e470f6606429 Mon Sep 17 00:00:00 2001
From: gbischof <bisc8233@gmail.com>
Date: Tue, 15 Sep 2020 11:14:05 -0400
Subject: [PATCH 1/2] copy discover_handlers from databroker

---
 event_model/__init__.py | 44 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/event_model/__init__.py b/event_model/__init__.py
index 4eedb9d2d..0351826fd 100644
--- a/event_model/__init__.py
+++ b/event_model/__init__.py
@@ -2211,3 +2211,47 @@ def default(self, obj):
                 return obj.item()
             return obj.tolist()
         return json.JSONEncoder.default(self, obj)
+
+def discover_handlers(entrypoint_group_name='databroker.handlers',
+                      skip_failures=True):
+    """
+    Discover handlers via entrypoints.
+    Parameters
+    ----------
+    entrypoint_group_name: str
+        Default is 'databroker.handlers', the "official" databroker entrypoint
+        for handlers.
+    skip_failures: boolean
+        True by default. Errors loading a handler class are converted to
+        warnings if this is True.
+    Returns
+    -------
+    handler_registry: dict
+        A suitable default handler registry
+    """
+    group = entrypoints.get_group_named(entrypoint_group_name)
+    group_all = entrypoints.get_group_all(entrypoint_group_name)
+    if len(group_all) != len(group):
+        # There are some name collisions. Let's go digging for them.
+        for name, matches in itertools.groupby(group_all, lambda ep: ep.name):
+            matches = list(matches)
+            if len(matches) != 1:
+                winner = group[name]
+                warnings.warn(
+                    f"There are {len(matches)} entrypoints for the "
+                    f"databroker handler spec {name!r}. "
+                    f"They are {matches}. The match {winner} has won the race.")
+    handler_registry = {}
+    for name, entrypoint in group.items():
+        try:
+            handler_class = entrypoint.load()
+        except Exception as exc:
+            if skip_failures:
+                warnings.warn(f"Skipping {entrypoint!r} which failed to load. "
+                              f"Exception: {exc!r}")
+                continue
+            else:
+                raise
+        handler_registry[name] = handler_class
+
+    return handler_registry

From 5127f236c7973ba0a8ddd9c8fb0bcfedb473fa4d Mon Sep 17 00:00:00 2001
From: gbischof <bisc8233@gmail.com>
Date: Tue, 15 Sep 2020 11:17:35 -0400
Subject: [PATCH 2/2] import entrypoints

---
 event_model/__init__.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/event_model/__init__.py b/event_model/__init__.py
index 0351826fd..3532a4eac 100644
--- a/event_model/__init__.py
+++ b/event_model/__init__.py
@@ -3,6 +3,7 @@
 from distutils.version import LooseVersion
 import copy
 import json
+import entrypoints
 from enum import Enum
 from functools import partial
 import itertools