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
|
#include "ReadBufferFromWebServer.h"
#include <Common/logger_useful.h>
#include <base/sleep.h>
#include <Core/Types.h>
#include <IO/ReadWriteBufferFromHTTP.h>
#include <IO/WriteBufferFromString.h>
#include <IO/Operators.h>
#include <thread>
namespace DB
{
namespace ErrorCodes
{
extern const int CANNOT_SEEK_THROUGH_FILE;
extern const int SEEK_POSITION_OUT_OF_BOUND;
extern const int LOGICAL_ERROR;
}
ReadBufferFromWebServer::ReadBufferFromWebServer(
const String & url_,
ContextPtr context_,
const ReadSettings & settings_,
bool use_external_buffer_,
size_t read_until_position_)
: ReadBufferFromFileBase(settings_.remote_fs_buffer_size, nullptr, 0)
, log(&Poco::Logger::get("ReadBufferFromWebServer"))
, context(context_)
, url(url_)
, buf_size(settings_.remote_fs_buffer_size)
, read_settings(settings_)
, use_external_buffer(use_external_buffer_)
, read_until_position(read_until_position_)
{
}
std::unique_ptr<ReadBuffer> ReadBufferFromWebServer::initialize()
{
Poco::URI uri(url);
if (read_until_position)
{
if (read_until_position < offset)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Attempt to read beyond right offset ({} > {})", offset, read_until_position - 1);
LOG_DEBUG(log, "Reading with range: {}-{}", offset, read_until_position);
}
else
{
LOG_DEBUG(log, "Reading from offset: {}", offset);
}
const auto & settings = context->getSettingsRef();
const auto & config = context->getConfigRef();
Poco::Timespan http_keep_alive_timeout{config.getUInt("keep_alive_timeout", 20), 0};
auto res = std::make_unique<ReadWriteBufferFromHTTP>(
uri,
Poco::Net::HTTPRequest::HTTP_GET,
ReadWriteBufferFromHTTP::OutStreamCallback(),
ConnectionTimeouts(std::max(Poco::Timespan(settings.http_connection_timeout.totalSeconds(), 0), Poco::Timespan(20, 0)),
settings.http_send_timeout,
std::max(Poco::Timespan(settings.http_receive_timeout.totalSeconds(), 0), Poco::Timespan(20, 0)),
settings.tcp_keep_alive_timeout,
http_keep_alive_timeout),
credentials,
0,
buf_size,
read_settings,
HTTPHeaderEntries{},
&context->getRemoteHostFilter(),
/* delay_initialization */true,
use_external_buffer);
if (read_until_position)
res->setReadUntilPosition(read_until_position);
if (offset)
res->seek(offset, SEEK_SET);
return res;
}
void ReadBufferFromWebServer::setReadUntilPosition(size_t position)
{
read_until_position = position;
impl.reset();
}
bool ReadBufferFromWebServer::nextImpl()
{
if (read_until_position)
{
if (read_until_position == offset)
return false;
if (read_until_position < offset)
throw Exception(ErrorCodes::LOGICAL_ERROR, "Attempt to read beyond right offset ({} > {})", offset, read_until_position - 1);
}
if (impl)
{
if (!use_external_buffer)
{
/**
* impl was initialized before, pass position() to it to make
* sure there is no pending data which was not read, because
* this branch means we read sequentially.
*/
impl->position() = position();
assert(!impl->hasPendingData());
}
}
else
{
impl = initialize();
}
if (use_external_buffer)
{
/**
* use_external_buffer -- means we read into the buffer which
* was passed to us from somewhere else. We do not check whether
* previously returned buffer was read or not, because this branch
* means we are prefetching data, each nextImpl() call we can fill
* a different buffer.
*/
impl->set(internal_buffer.begin(), internal_buffer.size());
assert(working_buffer.begin() != nullptr);
assert(!internal_buffer.empty());
}
auto result = impl->next();
if (result)
{
BufferBase::set(impl->buffer().begin(), impl->buffer().size(), impl->offset());
offset += working_buffer.size();
}
return result;
}
off_t ReadBufferFromWebServer::seek(off_t offset_, int whence)
{
if (impl)
throw Exception(ErrorCodes::CANNOT_SEEK_THROUGH_FILE, "Seek is allowed only before first read attempt from the buffer");
if (whence != SEEK_SET)
throw Exception(ErrorCodes::CANNOT_SEEK_THROUGH_FILE, "Only SEEK_SET mode is allowed");
if (offset_ < 0)
throw Exception(ErrorCodes::SEEK_POSITION_OUT_OF_BOUND, "Seek position is out of bounds. Offset: {}", offset_);
offset = offset_;
return offset;
}
off_t ReadBufferFromWebServer::getPosition()
{
return offset - available();
}
}
|
