Jeff Kaufman
35dd83397e
We want people to be able to install ngx_pagespeed like any other nginx module. If PSOL were a full-fledged library with a stable interface we could simply say "install PSOL" which might be as easy as `apt-get install psol-dev`, but it's not. Instead we directly include a precompiled binary library along with its headers. By building the binaries on something sufficiently old (Centos 5.4) they should work pretty much everywhere someone might think to run ngx_pagespeed, but building from source is still a documented option if they don't. Headers and binaries are from trunk of r2338, as documented in the READMEs.
112 lines
3.9 KiB
C++
112 lines
3.9 KiB
C++
/*
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* Copyright 2012 Google Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// Author: nikhilmadan@google.com (Nikhil Madan)
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#ifndef NET_INSTAWEB_HTTP_PUBLIC_RATE_CONTROLLER_H_
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#define NET_INSTAWEB_HTTP_PUBLIC_RATE_CONTROLLER_H_
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#include <map>
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#include "net/instaweb/util/public/basictypes.h"
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#include "net/instaweb/util/public/ref_counted_ptr.h"
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#include "net/instaweb/util/public/scoped_ptr.h"
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#include "net/instaweb/util/public/string.h"
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namespace net_instaweb {
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class AbstractMutex;
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class AsyncFetch;
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class MessageHandler;
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class Statistics;
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class ThreadSystem;
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class TimedVariable;
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class UrlAsyncFetcher;
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class Variable;
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// Controller which limits the number of outgoing fetches per domain. If the
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// fetch is for a user-facing request, this sends the request out anyway and
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// updates the count for number of outgoing fetches.
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// For non-user facing requests, this checks that the number of outgoing fetches
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// for this domain is less than the limit. If less than the limit, it sends
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// the fetch out and updates the count. If greater than the per-domain limit,
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// and if the global queue size is within the limit, it queues the request up.
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// However, if the global queue size is above the limit, it drops the request.
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// If a request is dropped, the response will have HttpAttributes::kXPsaLoadShed
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// set on the response headers.
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//
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// Note: this requires working statistics to work.
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class RateController {
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public:
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static const char kQueuedFetchCount[];
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static const char kDroppedFetchCount[];
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static const char kCurrentGlobalFetchQueueSize[];
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RateController(int max_global_queue_size,
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int per_host_outgoing_request_threshold,
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int per_host_queued_request_threshold,
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ThreadSystem* thread_system,
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Statistics* statistics);
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virtual ~RateController();
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// Applies our shaping policies, and either (eventually) asks fetcher to
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// fetch the given URL or drops it.
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void Fetch(UrlAsyncFetcher* fetcher,
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const GoogleString& url,
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MessageHandler* message_handler,
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AsyncFetch* fetch);
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// Initializes statistics variables associated with this class.
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static void InitStats(Statistics* statistics);
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private:
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class HostFetchInfo;
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class CustomFetch;
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friend class CustomFetch;
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typedef RefCountedPtr<HostFetchInfo> HostFetchInfoPtr;
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typedef std::map<GoogleString, HostFetchInfoPtr*> HostFetchInfoMap;
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// Delete the fetch info from fetch_info_map_ if possible.
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void DeleteFetchInfoIfPossible(const HostFetchInfoPtr& fetch_info);
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// The maximum permissible size of the global queue.
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const int max_global_queue_size_;
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// The maximum number of outgoing requests allowed per host.
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const int per_host_outgoing_request_threshold_;
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// The maximum number of queued requests allowed per host.
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const int per_host_queued_request_threshold_;
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ThreadSystem* thread_system_;
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// Map containing per-host information tracking outgoing and queued fetches.
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HostFetchInfoMap fetch_info_map_;
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scoped_ptr<AbstractMutex> mutex_;
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TimedVariable* queued_fetch_count_;
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TimedVariable* dropped_fetch_count_;
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// Using a variable here, since we want to be able to track this in the server
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// statistics.
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Variable* current_global_fetch_queue_size_;
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DISALLOW_COPY_AND_ASSIGN(RateController);
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};
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} // namespace net_instaweb
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#endif // NET_INSTAWEB_HTTP_PUBLIC_RATE_CONTROLLER_H_
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