summaryrefslogtreecommitdiff
path: root/indra/newview/llhttpretrypolicy.cpp
blob: c5692554c66782484843a3515d106892a83acb8c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
/**
 * @file llhttpretrypolicy.h
 * @brief Header for a retry policy class intended for use with http responders.
 *
 * $LicenseInfo:firstyear=2013&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2013, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "llviewerprecompiledheaders.h"
#include "llhttpretrypolicy.h"

namespace
{
    // Moved from httpconstants.h... only used in this file.
    bool isHttpServerErrorStatus(S32 status)
    {
        // Status 499 is sometimes used for re-interpreted status 2xx errors.
        // Allow retry of these, since we don't have enough information in this
        // context to know if this will always fail.
        if (HTTP_INTERNAL_ERROR == status) return true;

        // Check for status 5xx.
        return((500 <= status) && (status < 600));
    }
}

LLAdaptiveRetryPolicy::LLAdaptiveRetryPolicy(F32 min_delay, F32 max_delay, F32 backoff_factor, U32 max_retries, bool retry_on_4xx):
    mMinDelay(min_delay),
    mMaxDelay(max_delay),
    mBackoffFactor(backoff_factor),
    mMaxRetries(max_retries),
    mRetryOn4xx(retry_on_4xx)
{
    init();
}

void LLAdaptiveRetryPolicy::init()
{
    mDelay = mMinDelay;
    mRetryCount = 0;
    mShouldRetry = true;
}

void LLAdaptiveRetryPolicy::reset()
{
    init();
}

bool LLAdaptiveRetryPolicy::getRetryAfter(const LLSD& headers, F32& retry_header_time)
{
    return (headers.has(HTTP_IN_HEADER_RETRY_AFTER)
            && getSecondsUntilRetryAfter(headers[HTTP_IN_HEADER_RETRY_AFTER].asStringRef(), retry_header_time));
}

bool LLAdaptiveRetryPolicy::getRetryAfter(const LLCore::HttpHeaders::ptr_t &headers, F32& retry_header_time)
{
    if (headers)
    {
        const std::string *retry_value = headers->find(HTTP_IN_HEADER_RETRY_AFTER.c_str());
        if (retry_value &&
            getSecondsUntilRetryAfter(*retry_value, retry_header_time))
        {
            return true;
        }
    }
    return false;
}

void LLAdaptiveRetryPolicy::onSuccess()
{
    init();
}

void LLAdaptiveRetryPolicy::onFailure(S32 status, const LLSD& headers)
{
    F32 retry_header_time{};
    bool has_retry_header_time = getRetryAfter(headers,retry_header_time);
    onFailureCommon(status, has_retry_header_time, retry_header_time);
}

void LLAdaptiveRetryPolicy::onFailure(const LLCore::HttpResponse *response)
{
    F32 retry_header_time{};
    const LLCore::HttpHeaders::ptr_t headers = response->getHeaders();
    bool has_retry_header_time = getRetryAfter(headers,retry_header_time);
    onFailureCommon(response->getStatus().getType(), has_retry_header_time, retry_header_time);
}

void LLAdaptiveRetryPolicy::onFailureCommon(S32 status, bool has_retry_header_time, F32 retry_header_time)
{
    if (!mShouldRetry)
    {
        LL_INFOS() << "keep on failing" << LL_ENDL;
        return;
    }
    if (mRetryCount > 0)
    {
        mDelay = llclamp(mDelay*mBackoffFactor,mMinDelay,mMaxDelay);
    }
    // Honor server Retry-After header.
    // Status 503 may ask us to wait for a certain amount of time before retrying.
    F32 wait_time = mDelay;
    if (has_retry_header_time)
    {
        wait_time = retry_header_time;
    }

    if (mRetryCount>=mMaxRetries)
    {
        LL_INFOS() << "Too many retries " << mRetryCount << ", will not retry" << LL_ENDL;
        mShouldRetry = false;
    }
    if (!mRetryOn4xx && !isHttpServerErrorStatus(status))
    {
        LL_INFOS() << "Non-server error " << status << ", will not retry" << LL_ENDL;
        mShouldRetry = false;
    }
    if (mShouldRetry)
    {
        LL_INFOS() << "Retry count " << mRetryCount << " should retry after " << wait_time << LL_ENDL;
        mRetryTimer.reset();
        mRetryTimer.setTimerExpirySec(wait_time);
    }
    mRetryCount++;
}


bool LLAdaptiveRetryPolicy::shouldRetry(F32& seconds_to_wait) const
{
    if (mRetryCount == 0)
    {
        // Called shouldRetry before any failure.
        seconds_to_wait = F32_MAX;
        return false;
    }
    seconds_to_wait = mShouldRetry ? (F32) mRetryTimer.getRemainingTimeF32() : F32_MAX;
    return mShouldRetry;
}

// Moved from httpconstants.  Only used by this file.
// Parses 'Retry-After' header contents and returns seconds until retry should occur.
/*static*/
bool LLAdaptiveRetryPolicy::getSecondsUntilRetryAfter(const std::string& retry_after, F32& seconds_to_wait)
{
    // *TODO:  This needs testing!   Not in use yet.
    // Examples of Retry-After headers:
    // Retry-After: Fri, 31 Dec 1999 23:59:59 GMT
    // Retry-After: 120

    // Check for number of seconds version, first:
    char* end = 0;
    // Parse as double
    double seconds = std::strtod(retry_after.c_str(), &end);
    if (end != 0 && *end == 0)
    {
        // Successful parse
        seconds_to_wait = (F32)seconds;
        return true;
    }

    // Parse rfc1123 date.
    time_t date = curl_getdate(retry_after.c_str(), NULL);
    if (-1 == date) return false;

    seconds_to_wait = (F32)((F64)date - LLTimer::getTotalSeconds());

    return true;
}