Force catch_errors into pipeline
This commit adds a hook for WSGI applications (e.g. proxy.server.Application) to modify their WSGI pipelines. This is currently used by the proxy server to ensure that catch_errors is present; if it is missing, it is inserted as the first middleware in the pipeline. This lets us write new, mandatory middlewares for Swift without breaking existing deployments on upgrade. Change-Id: Ibed0f2edb6f80c25be182b3d4544e6a67c5050ad
This commit is contained in:
Samuel Merritt
parent
1bb6563a19
commit
a49fd3d8de
@ -16,6 +16,7 @@
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"""WSGI tools for use with swift."""
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import errno
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import inspect
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import os
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import signal
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import time
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@ -109,7 +110,6 @@ def wrap_conf_type(f):
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appconfig = wrap_conf_type(loadwsgi.appconfig)
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loadapp = wrap_conf_type(loadwsgi.loadapp)
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def monkey_patch_mimetools():
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@ -197,6 +197,111 @@ class RestrictedGreenPool(GreenPool):
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self.waitall()
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class PipelineWrapper(object):
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"""
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This class provides a number of utility methods for
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modifying the composition of a wsgi pipeline.
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"""
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def __init__(self, context):
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self.context = context
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def __contains__(self, entry_point_name):
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try:
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self.index(entry_point_name)
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return True
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except ValueError:
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return False
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def _format_for_display(self, ctx):
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if ctx.entry_point_name:
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return ctx.entry_point_name
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elif inspect.isfunction(ctx.object):
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# ctx.object is a reference to the actual filter_factory
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# function, so we pretty-print that. It's not the nice short
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# entry point, but it beats "<unknown>".
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#
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# These happen when, instead of something like
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#
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# use = egg:swift#healthcheck
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#
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# you have something like this:
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#
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# paste.filter_factory = \
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# swift.common.middleware.healthcheck:filter_factory
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return "%s:%s" % (inspect.getmodule(ctx.object).__name__,
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ctx.object.__name__)
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else:
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# No idea what this is
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return "<unknown context>"
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def __str__(self):
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parts = [self._format_for_display(ctx)
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for ctx in self.context.filter_contexts]
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parts.append(self._format_for_display(self.context.app_context))
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return " ".join(parts)
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def create_filter(self, entry_point_name):
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"""
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Creates a context for a filter that can subsequently be added
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to a pipeline context.
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:param entry_point_name: entry point of the middleware (Swift only)
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:returns: a filter context
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"""
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spec = 'egg:swift#' + entry_point_name
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ctx = loadwsgi.loadcontext(loadwsgi.FILTER, spec,
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global_conf=self.context.global_conf)
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ctx.protocol = 'paste.filter_factory'
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return ctx
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def index(self, entry_point_name):
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"""
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Returns the first index of the given entry point name in the pipeline.
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Raises ValueError if the given module is not in the pipeline.
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"""
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for i, ctx in enumerate(self.context.filter_contexts):
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if ctx.entry_point_name == entry_point_name:
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return i
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raise ValueError("%s is not in pipeline" % (entry_point_name,))
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def insert_filter(self, ctx, index=0):
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"""
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Inserts a filter module into the pipeline context.
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:param ctx: the context to be inserted
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:param index: (optional) index at which filter should be
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inserted in the list of pipeline filters. Default
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is 0, which means the start of the pipeline.
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"""
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self.context.filter_contexts.insert(index, ctx)
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def loadcontext(object_type, uri, name=None, relative_to=None,
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global_conf=None):
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add_conf_type = wrap_conf_type(lambda x: x)
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return loadwsgi.loadcontext(object_type, add_conf_type(uri), name=name,
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relative_to=relative_to,
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global_conf=global_conf)
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def loadapp(conf_file, global_conf):
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"""
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Loads a context from a config file, and if the context is a pipeline
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then presents the app with the opportunity to modify the pipeline.
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"""
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ctx = loadcontext(loadwsgi.APP, conf_file, global_conf=global_conf)
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if ctx.object_type.name == 'pipeline':
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# give app the opportunity to modify the pipeline context
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app = ctx.app_context.create()
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func = getattr(app, 'modify_wsgi_pipeline', None)
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if func:
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func(PipelineWrapper(ctx))
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return ctx.create()
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def run_server(conf, logger, sock, global_conf=None):
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# Ensure TZ environment variable exists to avoid stat('/etc/localtime') on
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# some platforms. This locks in reported times to the timezone in which
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@ -38,6 +38,22 @@ from swift.common.swob import HTTPBadRequest, HTTPForbidden, \
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HTTPServerError, HTTPException, Request
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# List of entry points for mandatory middlewares.
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#
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# Fields:
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#
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# "name" (required) is the entry point name from setup.py.
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#
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# "after" (optional) is a list of middlewares that this middleware should come
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# after. Default is for the middleware to go at the start of the pipeline. Any
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# middlewares in the "after" list that are not present in the pipeline will be
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# ignored, so you can safely name optional middlewares to come after. For
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# example, 'after: ["catch_errors", "bulk"]' would install this middleware
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# after catch_errors and bulk if both were present, but if bulk were absent,
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# would just install it after catch_errors.
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required_filters = [{'name': 'catch_errors'}]
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class Application(object):
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"""WSGI application for the proxy server."""
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@ -478,6 +494,37 @@ class Application(object):
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{'type': typ, 'ip': node['ip'], 'port': node['port'],
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'device': node['device'], 'info': additional_info})
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def modify_wsgi_pipeline(self, pipe):
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"""
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Called during WSGI pipeline creation. Modifies the WSGI pipeline
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context to ensure that mandatory middleware is present in the pipeline.
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:param pipe: A PipelineWrapper object
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"""
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pipeline_was_modified = False
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for filter_spec in reversed(required_filters):
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filter_name = filter_spec['name']
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if filter_name not in pipe:
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afters = filter_spec.get('after', [])
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insert_at = 0
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for after in afters:
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try:
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insert_at = max(insert_at, pipe.index(after) + 1)
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except ValueError: # not in pipeline; ignore it
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pass
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self.logger.info(
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'Adding required filter %s to pipeline at position %d' %
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(filter_name, insert_at))
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ctx = pipe.create_filter(filter_name)
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pipe.insert_filter(ctx, index=insert_at)
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pipeline_was_modified = True
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if pipeline_was_modified:
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self.logger.info("Pipeline was modified. New pipeline is \"%s\".",
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pipe)
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else:
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self.logger.debug("Pipeline is \"%s\"", pipe)
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def app_factory(global_conf, **local_conf):
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"""paste.deploy app factory for creating WSGI proxy apps."""
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@ -42,7 +42,7 @@ from swift.common import wsgi, utils, ring
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from test.unit import temptree
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from mock import patch
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from paste.deploy import loadwsgi
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def _fake_rings(tmpdir):
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@ -126,14 +126,11 @@ class TestWSGI(unittest.TestCase):
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swift_dir = TEMPDIR
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[pipeline:main]
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pipeline = catch_errors proxy-server
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pipeline = proxy-server
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[app:proxy-server]
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use = egg:swift#proxy
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conn_timeout = 0.2
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[filter:catch_errors]
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use = egg:swift#catch_errors
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"""
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contents = dedent(config)
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with temptree(['proxy-server.conf']) as t:
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@ -143,7 +140,7 @@ class TestWSGI(unittest.TestCase):
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_fake_rings(t)
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app, conf, logger, log_name = wsgi.init_request_processor(
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conf_file, 'proxy-server')
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# verify pipeline is catch_errors -> proxy-servery
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# verify pipeline is catch_errors -> proxy-server
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expected = swift.common.middleware.catch_errors.CatchErrorMiddleware
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self.assert_(isinstance(app, expected))
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self.assert_(isinstance(app.app, swift.proxy.server.Application))
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@ -179,14 +176,15 @@ class TestWSGI(unittest.TestCase):
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}
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# strip indent from test config contents
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config_dir = dict((f, dedent(c)) for (f, c) in config_dir.items())
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with temptree(*zip(*config_dir.items())) as conf_root:
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conf_dir = os.path.join(conf_root, 'proxy-server.conf.d')
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with open(os.path.join(conf_dir, 'swift.conf'), 'w') as f:
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f.write('[DEFAULT]\nswift_dir = %s' % conf_root)
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_fake_rings(conf_root)
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app, conf, logger, log_name = wsgi.init_request_processor(
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conf_dir, 'proxy-server')
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# verify pipeline is catch_errors -> proxy-servery
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with mock.patch('swift.proxy.server.Application.modify_wsgi_pipeline'):
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with temptree(*zip(*config_dir.items())) as conf_root:
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conf_dir = os.path.join(conf_root, 'proxy-server.conf.d')
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with open(os.path.join(conf_dir, 'swift.conf'), 'w') as f:
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f.write('[DEFAULT]\nswift_dir = %s' % conf_root)
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_fake_rings(conf_root)
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app, conf, logger, log_name = wsgi.init_request_processor(
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conf_dir, 'proxy-server')
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# verify pipeline is catch_errors -> proxy-server
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expected = swift.common.middleware.catch_errors.CatchErrorMiddleware
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self.assert_(isinstance(app, expected))
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self.assert_(isinstance(app.app, swift.proxy.server.Application))
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@ -333,12 +331,14 @@ class TestWSGI(unittest.TestCase):
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with open(conf_file, 'w') as f:
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f.write(contents.replace('TEMPDIR', t))
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_fake_rings(t)
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with patch('swift.common.wsgi.wsgi') as _wsgi:
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with patch('swift.common.wsgi.eventlet') as _eventlet:
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conf = wsgi.appconfig(conf_file)
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logger = logging.getLogger('test')
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sock = listen(('localhost', 0))
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wsgi.run_server(conf, logger, sock)
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with mock.patch('swift.proxy.server.Application.'
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'modify_wsgi_pipeline'):
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with mock.patch('swift.common.wsgi.wsgi') as _wsgi:
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with mock.patch('swift.common.wsgi.eventlet') as _eventlet:
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conf = wsgi.appconfig(conf_file)
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logger = logging.getLogger('test')
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sock = listen(('localhost', 0))
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wsgi.run_server(conf, logger, sock)
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self.assertEquals('HTTP/1.0',
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_wsgi.HttpProtocol.default_request_version)
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self.assertEquals(30, _wsgi.WRITE_TIMEOUT)
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@ -379,14 +379,16 @@ class TestWSGI(unittest.TestCase):
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with open(os.path.join(conf_dir, 'swift.conf'), 'w') as f:
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f.write('[DEFAULT]\nswift_dir = %s' % conf_root)
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_fake_rings(conf_root)
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with patch('swift.common.wsgi.wsgi') as _wsgi:
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with patch('swift.common.wsgi.eventlet') as _eventlet:
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with patch.dict('os.environ', {'TZ': ''}):
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conf = wsgi.appconfig(conf_dir)
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logger = logging.getLogger('test')
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sock = listen(('localhost', 0))
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wsgi.run_server(conf, logger, sock)
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self.assert_(os.environ['TZ'] is not '')
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with mock.patch('swift.proxy.server.Application.'
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'modify_wsgi_pipeline'):
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with mock.patch('swift.common.wsgi.wsgi') as _wsgi:
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with mock.patch('swift.common.wsgi.eventlet') as _eventlet:
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with mock.patch.dict('os.environ', {'TZ': ''}):
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conf = wsgi.appconfig(conf_dir)
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logger = logging.getLogger('test')
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sock = listen(('localhost', 0))
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wsgi.run_server(conf, logger, sock)
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self.assert_(os.environ['TZ'] is not '')
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self.assertEquals('HTTP/1.0',
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_wsgi.HttpProtocol.default_request_version)
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@ -667,5 +669,229 @@ class TestWSGIContext(unittest.TestCase):
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self.assertRaises(StopIteration, iterator.next)
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class TestPipelineWrapper(unittest.TestCase):
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def setUp(self):
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config = """
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[DEFAULT]
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swift_dir = TEMPDIR
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[pipeline:main]
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pipeline = healthcheck catch_errors tempurl proxy-server
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[app:proxy-server]
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use = egg:swift#proxy
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conn_timeout = 0.2
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[filter:catch_errors]
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use = egg:swift#catch_errors
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[filter:healthcheck]
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use = egg:swift#healthcheck
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[filter:tempurl]
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paste.filter_factory = swift.common.middleware.tempurl:filter_factory
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"""
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contents = dedent(config)
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with temptree(['proxy-server.conf']) as t:
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conf_file = os.path.join(t, 'proxy-server.conf')
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with open(conf_file, 'w') as f:
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f.write(contents.replace('TEMPDIR', t))
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ctx = wsgi.loadcontext(loadwsgi.APP, conf_file, global_conf={})
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self.pipe = wsgi.PipelineWrapper(ctx)
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def _entry_point_names(self):
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# Helper method to return a list of the entry point names for the
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# filters in the pipeline.
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return [c.entry_point_name for c in self.pipe.context.filter_contexts]
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def test_insert_filter(self):
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original_modules = ['healthcheck', 'catch_errors', None]
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self.assertEqual(self._entry_point_names(), original_modules)
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self.pipe.insert_filter(self.pipe.create_filter('catch_errors'))
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expected_modules = ['catch_errors', 'healthcheck',
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'catch_errors', None]
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self.assertEqual(self._entry_point_names(), expected_modules)
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def test_str(self):
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self.assertEqual(
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str(self.pipe),
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"healthcheck catch_errors " +
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"swift.common.middleware.tempurl:filter_factory proxy")
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def test_str_unknown_filter(self):
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self.pipe.context.filter_contexts[0].entry_point_name = None
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self.pipe.context.filter_contexts[0].object = 'mysterious'
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self.assertEqual(
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str(self.pipe),
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"<unknown context> catch_errors " +
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"swift.common.middleware.tempurl:filter_factory proxy")
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class TestPipelineModification(unittest.TestCase):
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def pipeline_modules(self, app):
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# This is rather brittle; it'll break if a middleware stores its app
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# anywhere other than an attribute named "app", but it works for now.
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pipe = []
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for _ in xrange(1000):
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pipe.append(app.__class__.__module__)
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if not hasattr(app, 'app'):
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break
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app = app.app
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return pipe
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def test_load_app(self):
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config = """
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[DEFAULT]
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swift_dir = TEMPDIR
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[pipeline:main]
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pipeline = healthcheck proxy-server
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[app:proxy-server]
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use = egg:swift#proxy
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conn_timeout = 0.2
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[filter:catch_errors]
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use = egg:swift#catch_errors
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[filter:healthcheck]
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use = egg:swift#healthcheck
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"""
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def modify_func(app, pipe):
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new = pipe.create_filter('catch_errors')
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pipe.insert_filter(new)
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contents = dedent(config)
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with temptree(['proxy-server.conf']) as t:
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conf_file = os.path.join(t, 'proxy-server.conf')
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with open(conf_file, 'w') as f:
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f.write(contents.replace('TEMPDIR', t))
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_fake_rings(t)
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with mock.patch(
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'swift.proxy.server.Application.modify_wsgi_pipeline',
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modify_func):
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app = wsgi.loadapp(conf_file, global_conf={})
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exp = swift.common.middleware.catch_errors.CatchErrorMiddleware
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self.assertTrue(isinstance(app, exp), app)
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exp = swift.common.middleware.healthcheck.HealthCheckMiddleware
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self.assertTrue(isinstance(app.app, exp), app.app)
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exp = swift.proxy.server.Application
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self.assertTrue(isinstance(app.app.app, exp), app.app.app)
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def test_proxy_unmodified_wsgi_pipeline(self):
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# Make sure things are sane even when we modify nothing
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config = """
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[DEFAULT]
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swift_dir = TEMPDIR
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[pipeline:main]
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pipeline = catch_errors proxy-server
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[app:proxy-server]
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use = egg:swift#proxy
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conn_timeout = 0.2
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[filter:catch_errors]
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use = egg:swift#catch_errors
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"""
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contents = dedent(config)
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with temptree(['proxy-server.conf']) as t:
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conf_file = os.path.join(t, 'proxy-server.conf')
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with open(conf_file, 'w') as f:
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f.write(contents.replace('TEMPDIR', t))
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_fake_rings(t)
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app = wsgi.loadapp(conf_file, global_conf={})
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self.assertEqual(self.pipeline_modules(app),
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['swift.common.middleware.catch_errors',
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'swift.proxy.server'])
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def test_proxy_modify_wsgi_pipeline(self):
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config = """
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[DEFAULT]
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swift_dir = TEMPDIR
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[pipeline:main]
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pipeline = healthcheck proxy-server
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[app:proxy-server]
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use = egg:swift#proxy
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conn_timeout = 0.2
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[filter:healthcheck]
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use = egg:swift#healthcheck
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"""
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|
||||
contents = dedent(config)
|
||||
with temptree(['proxy-server.conf']) as t:
|
||||
conf_file = os.path.join(t, 'proxy-server.conf')
|
||||
with open(conf_file, 'w') as f:
|
||||
f.write(contents.replace('TEMPDIR', t))
|
||||
_fake_rings(t)
|
||||
app = wsgi.loadapp(conf_file, global_conf={})
|
||||
|
||||
self.assertEqual(self.pipeline_modules(app)[0],
|
||||
'swift.common.middleware.catch_errors')
|
||||
|
||||
def test_proxy_modify_wsgi_pipeline_ordering(self):
|
||||
config = """
|
||||
[DEFAULT]
|
||||
swift_dir = TEMPDIR
|
||||
|
||||
[pipeline:main]
|
||||
pipeline = healthcheck proxy-logging bulk tempurl proxy-server
|
||||
|
||||
[app:proxy-server]
|
||||
use = egg:swift#proxy
|
||||
conn_timeout = 0.2
|
||||
|
||||
[filter:healthcheck]
|
||||
use = egg:swift#healthcheck
|
||||
|
||||
[filter:proxy-logging]
|
||||
use = egg:swift#proxy_logging
|
||||
|
||||
[filter:bulk]
|
||||
use = egg:swift#bulk
|
||||
|
||||
[filter:tempurl]
|
||||
use = egg:swift#tempurl
|
||||
"""
|
||||
|
||||
new_req_filters = [
|
||||
# not in pipeline, no afters
|
||||
{'name': 'catch_errors'},
|
||||
# already in pipeline
|
||||
{'name': 'proxy_logging',
|
||||
'after': ['catch_errors']},
|
||||
# not in pipeline, comes after more than one thing
|
||||
{'name': 'container_quotas',
|
||||
'after': ['catch_errors', 'bulk']}]
|
||||
|
||||
contents = dedent(config)
|
||||
with temptree(['proxy-server.conf']) as t:
|
||||
conf_file = os.path.join(t, 'proxy-server.conf')
|
||||
with open(conf_file, 'w') as f:
|
||||
f.write(contents.replace('TEMPDIR', t))
|
||||
_fake_rings(t)
|
||||
with mock.patch.object(swift.proxy.server, 'required_filters',
|
||||
new_req_filters):
|
||||
app = wsgi.loadapp(conf_file, global_conf={})
|
||||
|
||||
self.assertEqual(self.pipeline_modules(app), [
|
||||
'swift.common.middleware.catch_errors',
|
||||
'swift.common.middleware.healthcheck',
|
||||
'swift.common.middleware.proxy_logging',
|
||||
'swift.common.middleware.bulk',
|
||||
'swift.common.middleware.container_quotas',
|
||||
'swift.common.middleware.tempurl',
|
||||
'swift.proxy.server'])
|
||||
|
||||
|
||||
if __name__ == '__main__':
|
||||
unittest.main()
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user