Make the dependencies more like a standard Python project and hook up the optional dependencies to setuptools (#4298)

7 files changed, 111 insertions, 158 deletions

diff --git a/README.rst b/README.rst
index 02b3db1bc6..c4df779ac7 100644
--- a/README.rst
+++ b/README.rst
@@ -86,7 +86,7 @@ Synapse is the reference Python/Twisted Matrix homeserver implementation.
 System requirements:
 
 - POSIX-compliant system (tested on Linux & OS X)
-- Python 3.5, 3.6, or 2.7
+- Python 3.5, 3.6, 3.7, or 2.7
 - At least 1GB of free RAM if you want to join large public rooms like #matrix:matrix.org
 
 Installing from source
@@ -148,7 +148,7 @@ To install the Synapse homeserver run::
     source ~/synapse/env/bin/activate
     pip install --upgrade pip
     pip install --upgrade setuptools
-    pip install matrix-synapse
+    pip install matrix-synapse[all]
 
 This installs Synapse, along with the libraries it uses, into a virtual
 environment under ``~/synapse/env``.  Feel free to pick a different directory
@@ -158,7 +158,7 @@ This Synapse installation can then be later upgraded by using pip again with the
 update flag::
 
     source ~/synapse/env/bin/activate
-    pip install -U matrix-synapse
+    pip install -U matrix-synapse[all]
 
 In case of problems, please see the _`Troubleshooting` section below.
 
@@ -826,8 +826,7 @@ to install using pip and a virtualenv::
 
     virtualenv -p python2.7 env
     source env/bin/activate
-    python -m synapse.python_dependencies | xargs pip install
-    pip install lxml mock
+    python -m pip install -e .[all]
 
 This will run a process of downloading and installing all the needed
 dependencies into a virtual env.
@@ -835,7 +834,7 @@ dependencies into a virtual env.
 Once this is done, you may wish to run Synapse's unit tests, to
 check that everything is installed as it should be::
 
-    PYTHONPATH="." trial tests
+    python -m twisted.trial tests
 
 This should end with a 'PASSED' result::
 
diff --git a/changelog.d/4298.feature b/changelog.d/4298.feature
new file mode 100644
index 0000000000..05ad70fe72
--- /dev/null
+++ b/changelog.d/4298.feature
@@ -0,0 +1 @@
+Synapse can now have its conditional/extra dependencies installed by pip. This functionality can be used by using `pip install matrix-synapse[feature]`, where feature is a comma separated list with the possible values "email.enable_notifs", "ldap3", "postgres", "saml2", "url_preview", and "test". If you want to install all optional dependencies, you can use "all" instead.
diff --git a/setup.py b/setup.py
index 00b69c43f5..55b1b10a77 100755
--- a/setup.py
+++ b/setup.py
@@ -84,13 +84,25 @@ version = exec_file(("synapse", "__init__.py"))["__version__"]
 dependencies = exec_file(("synapse", "python_dependencies.py"))
 long_description = read_file(("README.rst",))
 
+REQUIREMENTS = dependencies['REQUIREMENTS']
+CONDITIONAL_REQUIREMENTS = dependencies['CONDITIONAL_REQUIREMENTS']
+
+# Make `pip install matrix-synapse[all]` install all the optional dependencies.
+ALL_OPTIONAL_REQUIREMENTS = set()
+
+for optional_deps in CONDITIONAL_REQUIREMENTS.values():
+    ALL_OPTIONAL_REQUIREMENTS = set(optional_deps) | ALL_OPTIONAL_REQUIREMENTS
+
+CONDITIONAL_REQUIREMENTS["all"] = list(ALL_OPTIONAL_REQUIREMENTS)
+
+
 setup(
     name="matrix-synapse",
     version=version,
     packages=find_packages(exclude=["tests", "tests.*"]),
     description="Reference homeserver for the Matrix decentralised comms protocol",
-    install_requires=dependencies['requirements'](include_conditional=True).keys(),
-    dependency_links=dependencies["DEPENDENCY_LINKS"].values(),
+    install_requires=REQUIREMENTS,
+    extras_require=CONDITIONAL_REQUIREMENTS,
     include_package_data=True,
     zip_safe=False,
     long_description=long_description,
diff --git a/synapse/app/__init__.py b/synapse/app/__init__.py
index c3afcc573b..233bf43fc8 100644
--- a/synapse/app/__init__.py
+++ b/synapse/app/__init__.py
@@ -22,11 +22,11 @@ sys.dont_write_bytecode = True
 
 try:
     python_dependencies.check_requirements()
-except python_dependencies.MissingRequirementError as e:
+except python_dependencies.DependencyException as e:
     message = "\n".join([
-        "Missing Requirement: %s" % (str(e),),
+        "Missing Requirements: %s" % (", ".join(e.dependencies),),
         "To install run:",
-        "    pip install --upgrade --force \"%s\"" % (e.dependency,),
+        "    pip install --upgrade --force %s" % (" ".join(e.dependencies),),
         "",
     ])
     sys.stderr.writelines(message)
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index f2064f9d0c..f3ac3d19f0 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -322,9 +322,6 @@ def setup(config_options):
 
     synapse.config.logger.setup_logging(config, use_worker_options=False)
 
-    # check any extra requirements we have now we have a config
-    check_requirements(config)
-
     events.USE_FROZEN_DICTS = config.use_frozen_dicts
 
     tls_server_context_factory = context_factory.ServerContextFactory(config)
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index 72a92cc462..2c65ef5856 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -15,175 +15,121 @@
 # limitations under the License.
 
 import logging
-from distutils.version import LooseVersion
+
+from pkg_resources import DistributionNotFound, VersionConflict, get_distribution
 
 logger = logging.getLogger(__name__)
 
-# this dict maps from python package name to a list of modules we expect it to
-# provide.
-#
-# the key is a "requirement specifier", as used as a parameter to `pip
-# install`[1], or an `install_requires` argument to `setuptools.setup` [2].
+
+# REQUIREMENTS is a simple list of requirement specifiers[1], and must be
+# installed. It is passed to setup() as install_requires in setup.py.
 #
-# the value is a sequence of strings; each entry should be the name of the
-# python module, optionally followed by a version assertion which can be either
-# ">=<ver>" or "==<ver>".
+# CONDITIONAL_REQUIREMENTS is the optional dependencies, represented as a dict
+# of lists. The dict key is the optional dependency name and can be passed to
+# pip when installing. The list is a series of requirement specifiers[1] to be
+# installed when that optional dependency requirement is specified. It is passed
+# to setup() as extras_require in setup.py
 #
 # [1] https://pip.pypa.io/en/stable/reference/pip_install/#requirement-specifiers.
-# [2] https://setuptools.readthedocs.io/en/latest/setuptools.html#declaring-dependencies
-REQUIREMENTS = {
-    "jsonschema>=2.5.1": ["jsonschema>=2.5.1"],
-    "frozendict>=1": ["frozendict"],
-    "unpaddedbase64>=1.1.0": ["unpaddedbase64>=1.1.0"],
-    "canonicaljson>=1.1.3": ["canonicaljson>=1.1.3"],
-    "signedjson>=1.0.0": ["signedjson>=1.0.0"],
-    "pynacl>=1.2.1": ["nacl>=1.2.1", "nacl.bindings"],
-    "service_identity>=16.0.0": ["service_identity>=16.0.0"],
-    "Twisted>=17.1.0": ["twisted>=17.1.0"],
-    "treq>=15.1": ["treq>=15.1"],
 
+REQUIREMENTS = [
+    "jsonschema>=2.5.1",
+    "frozendict>=1",
+    "unpaddedbase64>=1.1.0",
+    "canonicaljson>=1.1.3",
+    "signedjson>=1.0.0",
+    "pynacl>=1.2.1",
+    "service_identity>=16.0.0",
+    "Twisted>=17.1.0",
+    "treq>=15.1",
     # Twisted has required pyopenssl 16.0 since about Twisted 16.6.
-    "pyopenssl>=16.0.0": ["OpenSSL>=16.0.0"],
-
-    "pyyaml>=3.11": ["yaml"],
-    "pyasn1>=0.1.9": ["pyasn1"],
-    "pyasn1-modules>=0.0.7": ["pyasn1_modules"],
-    "daemonize>=2.3.1": ["daemonize"],
-    "bcrypt>=3.1.0": ["bcrypt>=3.1.0"],
-    "pillow>=3.1.2": ["PIL"],
-    "sortedcontainers>=1.4.4": ["sortedcontainers"],
-    "psutil>=2.0.0": ["psutil>=2.0.0"],
-    "pymacaroons-pynacl>=0.9.3": ["pymacaroons"],
-    "msgpack-python>=0.4.2": ["msgpack"],
-    "phonenumbers>=8.2.0": ["phonenumbers"],
-    "six>=1.10": ["six"],
-
+    "pyopenssl>=16.0.0",
+    "pyyaml>=3.11",
+    "pyasn1>=0.1.9",
+    "pyasn1-modules>=0.0.7",
+    "daemonize>=2.3.1",
+    "bcrypt>=3.1.0",
+    "pillow>=3.1.2",
+    "sortedcontainers>=1.4.4",
+    "psutil>=2.0.0",
+    "pymacaroons-pynacl>=0.9.3",
+    "msgpack-python>=0.4.2",
+    "phonenumbers>=8.2.0",
+    "six>=1.10",
     # prometheus_client 0.4.0 changed the format of counter metrics
     # (cf https://github.com/matrix-org/synapse/issues/4001)
-    "prometheus_client>=0.0.18,<0.4.0": ["prometheus_client"],
-
+    "prometheus_client>=0.0.18,<0.4.0",
     # we use attr.s(slots), which arrived in 16.0.0
-    "attrs>=16.0.0": ["attr>=16.0.0"],
-    "netaddr>=0.7.18": ["netaddr"],
-}
+    "attrs>=16.0.0",
+    "netaddr>=0.7.18",
+]
 
 CONDITIONAL_REQUIREMENTS = {
-    "email.enable_notifs": {
-        "Jinja2>=2.8": ["Jinja2>=2.8"],
-        "bleach>=1.4.2": ["bleach>=1.4.2"],
-    },
-    "matrix-synapse-ldap3": {
-        "matrix-synapse-ldap3>=0.1": ["ldap_auth_provider"],
-    },
-    "postgres": {
-        "psycopg2>=2.6": ["psycopg2"]
-    },
-    "saml2": {
-        "pysaml2>=4.5.0": ["saml2"],
-    },
+    "email.enable_notifs": ["Jinja2>=2.8", "bleach>=1.4.2"],
+    "matrix-synapse-ldap3": ["matrix-synapse-ldap3>=0.1"],
+    "postgres": ["psycopg2>=2.6"],
+    "saml2": ["pysaml2>=4.5.0"],
+    "url_preview": ["lxml>=3.5.0"],
+    "test": ["mock>=2.0"],
 }
 
 
-def requirements(config=None, include_conditional=False):
-    reqs = REQUIREMENTS.copy()
-    if include_conditional:
-        for _, req in CONDITIONAL_REQUIREMENTS.items():
-            reqs.update(req)
-    return reqs
+def list_requirements():
+    deps = set(REQUIREMENTS)
+    for opt in CONDITIONAL_REQUIREMENTS.values():
+        deps = set(opt) | deps
 
+    return list(deps)
 
-def github_link(project, version, egg):
-    return "https://github.com/%s/tarball/%s/#egg=%s" % (project, version, egg)
 
+class DependencyException(Exception):
+    @property
+    def dependencies(self):
+        for i in self.args[0]:
+            yield '"' + i + '"'
 
-DEPENDENCY_LINKS = {
-}
 
+def check_requirements(_get_distribution=get_distribution):
+
+    deps_needed = []
+    errors = []
 
-class MissingRequirementError(Exception):
-    def __init__(self, message, module_name, dependency):
-        super(MissingRequirementError, self).__init__(message)
-        self.module_name = module_name
-        self.dependency = dependency
-
-
-def check_requirements(config=None):
-    """Checks that all the modules needed by synapse have been correctly
-    installed and are at the correct version"""
-    for dependency, module_requirements in (
-            requirements(config, include_conditional=False).items()):
-        for module_requirement in module_requirements:
-            if ">=" in module_requirement:
-                module_name, required_version = module_requirement.split(">=")
-                version_test = ">="
-            elif "==" in module_requirement:
-                module_name, required_version = module_requirement.split("==")
-                version_test = "=="
-            else:
-                module_name = module_requirement
-                version_test = None
-
-            try:
-                module = __import__(module_name)
-            except ImportError:
-                logging.exception(
-                    "Can't import %r which is part of %r",
-                    module_name, dependency
-                )
-                raise MissingRequirementError(
-                    "Can't import %r which is part of %r"
-                    % (module_name, dependency), module_name, dependency
-                )
-            version = getattr(module, "__version__", None)
-            file_path = getattr(module, "__file__", None)
-            logger.info(
-                "Using %r version %r from %r to satisfy %r",
-                module_name, version, file_path, dependency
+    # Check the base dependencies exist -- they all must be installed.
+    for dependency in REQUIREMENTS:
+        try:
+            _get_distribution(dependency)
+        except VersionConflict as e:
+            deps_needed.append(dependency)
+            errors.append(
+                "Needed %s, got %s==%s"
+                % (dependency, e.dist.project_name, e.dist.version)
             )
+        except DistributionNotFound:
+            deps_needed.append(dependency)
+            errors.append("Needed %s but it was not installed" % (dependency,))
 
-            if version_test == ">=":
-                if version is None:
-                    raise MissingRequirementError(
-                        "Version of %r isn't set as __version__ of module %r"
-                        % (dependency, module_name), module_name, dependency
-                    )
-                if LooseVersion(version) < LooseVersion(required_version):
-                    raise MissingRequirementError(
-                        "Version of %r in %r is too old. %r < %r"
-                        % (dependency, file_path, version, required_version),
-                        module_name, dependency
-                    )
-            elif version_test == "==":
-                if version is None:
-                    raise MissingRequirementError(
-                        "Version of %r isn't set as __version__ of module %r"
-                        % (dependency, module_name), module_name, dependency
-                    )
-                if LooseVersion(version) != LooseVersion(required_version):
-                    raise MissingRequirementError(
-                        "Unexpected version of %r in %r. %r != %r"
-                        % (dependency, file_path, version, required_version),
-                        module_name, dependency
-                    )
+    # Check the optional dependencies are up to date. We allow them to not be
+    # installed.
+    OPTS = sum(CONDITIONAL_REQUIREMENTS.values(), [])
 
+    for dependency in OPTS:
+        try:
+            _get_distribution(dependency)
+        except VersionConflict:
+            deps_needed.append(dependency)
+            errors.append("Needed %s but it was not installed" % (dependency,))
+        except DistributionNotFound:
+            # If it's not found, we don't care
+            pass
 
-def list_requirements():
-    result = []
-    linked = []
-    for link in DEPENDENCY_LINKS.values():
-        egg = link.split("#egg=")[1]
-        linked.append(egg.split('-')[0])
-        result.append(link)
-    for requirement in requirements(include_conditional=True):
-        is_linked = False
-        for link in linked:
-            if requirement.replace('-', '_').startswith(link):
-                is_linked = True
-        if not is_linked:
-            result.append(requirement)
-    return result
+    if deps_needed:
+        for e in errors:
+            logging.exception(e)
+
+        raise DependencyException(deps_needed)
 
 
 if __name__ == "__main__":
     import sys
+
     sys.stdout.writelines(req + "\n" for req in list_requirements())
diff --git a/tox.ini b/tox.ini
index f5f07cb690..a0f5486829 100644
--- a/tox.ini
+++ b/tox.ini
@@ -9,9 +9,6 @@ deps =
     junitxml
     coverage
 
-    # needed by some of the tests
-    lxml
-
     # cyptography 2.2 requires setuptools >= 18.5
     #
     # older versions of virtualenv (?) give us a virtualenv with the same
@@ -33,6 +30,7 @@ setenv =
 [testenv]
 deps =
     {[base]deps}
+extras = all
 
 whitelist_externals =
     sh