Setuptools entry_points plugins

docs/index.rst

@@ -7,6 +7,7 @@ Welcome to the Let's Encrypt client documentation!
    intro
    using
    contributing
+   plugins
 
 .. toctree::
    :maxdepth: 1

docs/plugins.rst

@@ -0,0 +1,5 @@
+=======
+Plugins
+=======
+
+You can find an example in ``examples/plugins/`` directory.

examples/plugins/letsencrypt_example_plugins.py

@@ -0,0 +1,16 @@
+"""Example Let's Encrypt plugins."""
+import zope.interface
+
+from letsencrypt.client import interfaces
+
+
+class Authenticator(object):
+    zope.interface.implements(interfaces.IAuthenticator)
+
+    description = 'Example Authenticator plugin'
+
+    def __init__(self, config):
+        self.config = config
+
+    # Implement all methods from IAuthenticator, remembering to add
+    # "self" as first argument, e.g. def prepare(self)...

examples/plugins/setup.py

@@ -0,0 +1,16 @@
+from setuptools import setup
+
+
+setup(
+    name='letsencrypt-example-plugins',
+    package='letsencrypt_example_plugins.py',
+    install_requires=[
+        'letsencrypt',
+        'zope.interface',
+    ],
+    entry_points={
+        'letsencrypt.authenticators': [
+            'example = letsencrypt_example_plugins:Authenticator',
+        ],
+    },
+)

letsencrypt/client/client.py

@@ -1,11 +1,15 @@
 """ACME protocol client class and helper functions."""
 import logging
 import os
+import pkg_resources
 import sys
 
 import Crypto.PublicKey.RSA
 import M2Crypto
 
+import zope.interface.exceptions
+import zope.interface.verify
+
 from letsencrypt.acme import messages
 from letsencrypt.acme.jose import util as jose_util
 
@@ -13,6 +17,7 @@ from letsencrypt.client import auth_handler
 from letsencrypt.client import client_authenticator
 from letsencrypt.client import crypto_util
 from letsencrypt.client import errors
+from letsencrypt.client import interfaces
 from letsencrypt.client import le_util
 from letsencrypt.client import network
 from letsencrypt.client import reverter
@@ -23,6 +28,28 @@ from letsencrypt.client.display import ops as display_ops
 from letsencrypt.client.display import enhancements
 
 
+SETUPTOOLS_AUTHENTICATORS_ENTRY_POINT = 'letsencrypt.authenticators'
+"""Setuptools entry point group name for Authenticator plugins."""
+
+
+def init_auths(config):
+    """Find (setuptools entry points) and initialize Authenticators."""
+    auths = {}
+    for entrypoint in pkg_resources.iter_entry_points(
+            SETUPTOOLS_AUTHENTICATORS_ENTRY_POINT):
+        auth_cls = entrypoint.load()
+        auth = auth_cls(config)
+        try:
+            zope.interface.verify.verifyObject(interfaces.IAuthenticator, auth)
+        except zope.interface.exceptions.BrokenImplementation:
+            logging.debug(
+                '"%s" object does not provide IAuthenticator, skipping',
+                entrypoint.name)
+        else:
+            auths[auth] = entrypoint.name
+    return auths
+
+
 class Client(object):
     """ACME protocol client.
 

letsencrypt/client/standalone_authenticator.py

@@ -33,7 +33,7 @@ class StandaloneAuthenticator(object):
 
     description = "Standalone Authenticator"
 
-    def __init__(self):
+    def __init__(self, unused_config):
         self.child_pid = None
         self.parent_pid = os.getpid()
         self.subproc_state = None

letsencrypt/client/tests/standalone_authenticator_test.py

@@ -51,7 +51,7 @@ class ChallPrefTest(unittest.TestCase):
     def setUp(self):
         from letsencrypt.client.standalone_authenticator import \
             StandaloneAuthenticator
-        self.authenticator = StandaloneAuthenticator()
+        self.authenticator = StandaloneAuthenticator(None)
 
     def test_chall_pref(self):
         self.assertEqual(self.authenticator.get_chall_pref("example.com"),
@@ -63,7 +63,7 @@ class SNICallbackTest(unittest.TestCase):
     def setUp(self):
         from letsencrypt.client.standalone_authenticator import \
             StandaloneAuthenticator
-        self.authenticator = StandaloneAuthenticator()
+        self.authenticator = StandaloneAuthenticator(None)
         test_key = pkg_resources.resource_string(
             __name__, "testdata/rsa256_key.pem")
         key = le_util.Key("foo", test_key)
@@ -106,7 +106,7 @@ class ClientSignalHandlerTest(unittest.TestCase):
     def setUp(self):
         from letsencrypt.client.standalone_authenticator import \
             StandaloneAuthenticator
-        self.authenticator = StandaloneAuthenticator()
+        self.authenticator = StandaloneAuthenticator(None)
         self.authenticator.tasks = {"foononce.acme.invalid": "stuff"}
         self.authenticator.child_pid = 12345
 
@@ -135,7 +135,7 @@ class SubprocSignalHandlerTest(unittest.TestCase):
     def setUp(self):
         from letsencrypt.client.standalone_authenticator import \
             StandaloneAuthenticator
-        self.authenticator = StandaloneAuthenticator()
+        self.authenticator = StandaloneAuthenticator(None)
         self.authenticator.tasks = {"foononce.acme.invalid": "stuff"}
         self.authenticator.child_pid = 12345
         self.authenticator.parent_pid = 23456
@@ -187,7 +187,7 @@ class AlreadyListeningTest(unittest.TestCase):
     def setUp(self):
         from letsencrypt.client.standalone_authenticator import \
             StandaloneAuthenticator
-        self.authenticator = StandaloneAuthenticator()
+        self.authenticator = StandaloneAuthenticator(None)
 
     @mock.patch("letsencrypt.client.standalone_authenticator.psutil."
                 "net_connections")
@@ -290,7 +290,7 @@ class PerformTest(unittest.TestCase):
     def setUp(self):
         from letsencrypt.client.standalone_authenticator import \
             StandaloneAuthenticator
-        self.authenticator = StandaloneAuthenticator()
+        self.authenticator = StandaloneAuthenticator(None)
 
         test_key = pkg_resources.resource_string(
             __name__, "testdata/rsa256_key.pem")
@@ -367,7 +367,7 @@ class StartListenerTest(unittest.TestCase):
     def setUp(self):
         from letsencrypt.client.standalone_authenticator import \
             StandaloneAuthenticator
-        self.authenticator = StandaloneAuthenticator()
+        self.authenticator = StandaloneAuthenticator(None)
 
     @mock.patch("letsencrypt.client.standalone_authenticator."
                 "Crypto.Random.atfork")
@@ -402,7 +402,7 @@ class DoParentProcessTest(unittest.TestCase):
     def setUp(self):
         from letsencrypt.client.standalone_authenticator import \
             StandaloneAuthenticator
-        self.authenticator = StandaloneAuthenticator()
+        self.authenticator = StandaloneAuthenticator(None)
 
     @mock.patch("letsencrypt.client.standalone_authenticator.signal.signal")
     @mock.patch("letsencrypt.client.standalone_authenticator."
@@ -452,7 +452,7 @@ class DoChildProcessTest(unittest.TestCase):
     def setUp(self):
         from letsencrypt.client.standalone_authenticator import \
             StandaloneAuthenticator
-        self.authenticator = StandaloneAuthenticator()
+        self.authenticator = StandaloneAuthenticator(None)
         test_key = pkg_resources.resource_string(
             __name__, "testdata/rsa256_key.pem")
         key = le_util.Key("foo", test_key)
@@ -545,7 +545,7 @@ class CleanupTest(unittest.TestCase):
     def setUp(self):
         from letsencrypt.client.standalone_authenticator import \
             StandaloneAuthenticator
-        self.authenticator = StandaloneAuthenticator()
+        self.authenticator = StandaloneAuthenticator(None)
         self.achall = achallenges.DVSNI(
             chall=challenges.DVSNI(r="whee", nonce="foononce"),
             domain="foo.example.com", key="key")
@@ -575,7 +575,7 @@ class MoreInfoTest(unittest.TestCase):
     def setUp(self):
         from letsencrypt.client.standalone_authenticator import (
             StandaloneAuthenticator)
-        self.authenticator = StandaloneAuthenticator()
+        self.authenticator = StandaloneAuthenticator(None)
 
     def test_more_info(self):
         """Make sure exceptions aren't raised."""
@@ -587,7 +587,7 @@ class InitTest(unittest.TestCase):
     def setUp(self):
         from letsencrypt.client.standalone_authenticator import (
             StandaloneAuthenticator)
-        self.authenticator = StandaloneAuthenticator()
+        self.authenticator = StandaloneAuthenticator(None)
 
     def test_prepare(self):
         """Make sure exceptions aren't raised.

letsencrypt/scripts/main.py

@@ -136,12 +136,10 @@ def main():  # pylint: disable=too-many-branches, too-many-statements
     if not args.eula:
         display_eula()
 
-    all_auths = [
-        configurator.ApacheConfigurator(config),
-        standalone.StandaloneAuthenticator(),
-    ]
+    all_auths = client.init_auths(config)
+    logging.debug('Initialized authenticators: %s', all_auths)
     try:
-        auth = client.determine_authenticator(all_auths)
+        auth = client.determine_authenticator(all_auths.keys())
     except errors.LetsEncryptClientError:
         logging.critical("No authentication mechanisms were found on your "
                          "system.")

setup.py

@@ -119,6 +119,12 @@ setup(
             'letsencrypt = letsencrypt.scripts.main:main',
             'jws = letsencrypt.acme.jose.jws:CLI.run',
         ],
+        'letsencrypt.authenticators': [
+            'apache = letsencrypt.client.apache.configurator'
+            ':ApacheConfigurator',
+            'standalone = letsencrypt.client.standalone_authenticator'
+            ':StandaloneAuthenticator',
+        ],
     },
 
     zip_safe=False,