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rocksdb/util/env_hdfs.cc

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// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
#ifdef USE_HDFS
#ifndef ROCKSDB_HDFS_FILE_C
#define ROCKSDB_HDFS_FILE_C
#include <algorithm>
#include <stdio.h>
#include <sys/time.h>
#include <time.h>
#include <iostream>
#include <sstream>
#include "rocksdb/env.h"
#include "rocksdb/status.h"
#include "hdfs/hdfs.h"
#include "hdfs/env_hdfs.h"
//
// This file defines an HDFS environment for rocksdb. It uses the libhdfs
// api to access HDFS. All HDFS files created by one instance of rocksdb
// will reside on the same HDFS cluster.
//
namespace rocksdb {
namespace {
// Log error message
static Status IOError(const std::string& context, int err_number) {
return Status::IOError(context, strerror(err_number));
}
// assume that there is one global logger for now. It is not thread-safe,
// but need not be because the logger is initialized at db-open time.
static Logger* mylog = nullptr;
// Used for reading a file from HDFS. It implements both sequential-read
// access methods as well as random read access methods.
class HdfsReadableFile: virtual public SequentialFile, virtual public RandomAccessFile {
private:
hdfsFS fileSys_;
std::string filename_;
hdfsFile hfile_;
public:
HdfsReadableFile(hdfsFS fileSys, const std::string& fname)
: fileSys_(fileSys), filename_(fname), hfile_(nullptr) {
Log(mylog, "[hdfs] HdfsReadableFile opening file %s\n",
filename_.c_str());
hfile_ = hdfsOpenFile(fileSys_, filename_.c_str(), O_RDONLY, 0, 0, 0);
Log(mylog, "[hdfs] HdfsReadableFile opened file %s hfile_=0x%p\n",
filename_.c_str(), hfile_);
}
virtual ~HdfsReadableFile() {
Log(mylog, "[hdfs] HdfsReadableFile closing file %s\n",
filename_.c_str());
hdfsCloseFile(fileSys_, hfile_);
Log(mylog, "[hdfs] HdfsReadableFile closed file %s\n",
filename_.c_str());
hfile_ = nullptr;
}
bool isValid() {
return hfile_ != nullptr;
}
// sequential access, read data at current offset in file
virtual Status Read(size_t n, Slice* result, char* scratch) {
Status s;
Log(mylog, "[hdfs] HdfsReadableFile reading %s %ld\n",
filename_.c_str(), n);
size_t bytes_read = hdfsRead(fileSys_, hfile_, scratch, (tSize)n);
Log(mylog, "[hdfs] HdfsReadableFile read %s\n", filename_.c_str());
*result = Slice(scratch, bytes_read);
if (bytes_read < n) {
if (feof()) {
// We leave status as ok if we hit the end of the file
} else {
// A partial read with an error: return a non-ok status
s = IOError(filename_, errno);
}
}
return s;
}
// random access, read data from specified offset in file
virtual Status Read(uint64_t offset, size_t n, Slice* result,
char* scratch) const {
Status s;
Log(mylog, "[hdfs] HdfsReadableFile preading %s\n", filename_.c_str());
ssize_t bytes_read = hdfsPread(fileSys_, hfile_, offset,
(void*)scratch, (tSize)n);
Log(mylog, "[hdfs] HdfsReadableFile pread %s\n", filename_.c_str());
*result = Slice(scratch, (bytes_read < 0) ? 0 : bytes_read);
if (bytes_read < 0) {
// An error: return a non-ok status
s = IOError(filename_, errno);
}
return s;
}
virtual Status Skip(uint64_t n) {
Log(mylog, "[hdfs] HdfsReadableFile skip %s\n", filename_.c_str());
// get current offset from file
tOffset current = hdfsTell(fileSys_, hfile_);
if (current < 0) {
return IOError(filename_, errno);
}
// seek to new offset in file
tOffset newoffset = current + n;
int val = hdfsSeek(fileSys_, hfile_, newoffset);
if (val < 0) {
return IOError(filename_, errno);
}
return Status::OK();
}
private:
// returns true if we are at the end of file, false otherwise
bool feof() {
Log(mylog, "[hdfs] HdfsReadableFile feof %s\n", filename_.c_str());
if (hdfsTell(fileSys_, hfile_) == fileSize()) {
return true;
}
return false;
}
// the current size of the file
tOffset fileSize() {
Log(mylog, "[hdfs] HdfsReadableFile fileSize %s\n", filename_.c_str());
hdfsFileInfo* pFileInfo = hdfsGetPathInfo(fileSys_, filename_.c_str());
tOffset size = 0L;
if (pFileInfo != nullptr) {
size = pFileInfo->mSize;
hdfsFreeFileInfo(pFileInfo, 1);
} else {
throw rocksdb::HdfsFatalException("fileSize on unknown file " +
filename_);
}
return size;
}
};
// Appends to an existing file in HDFS.
class HdfsWritableFile: public WritableFile {
private:
hdfsFS fileSys_;
std::string filename_;
hdfsFile hfile_;
public:
HdfsWritableFile(hdfsFS fileSys, const std::string& fname)
: fileSys_(fileSys), filename_(fname) , hfile_(nullptr) {
Log(mylog, "[hdfs] HdfsWritableFile opening %s\n", filename_.c_str());
hfile_ = hdfsOpenFile(fileSys_, filename_.c_str(), O_WRONLY, 0, 0, 0);
Log(mylog, "[hdfs] HdfsWritableFile opened %s\n", filename_.c_str());
assert(hfile_ != nullptr);
}
virtual ~HdfsWritableFile() {
if (hfile_ != nullptr) {
Log(mylog, "[hdfs] HdfsWritableFile closing %s\n", filename_.c_str());
hdfsCloseFile(fileSys_, hfile_);
Log(mylog, "[hdfs] HdfsWritableFile closed %s\n", filename_.c_str());
hfile_ = nullptr;
}
}
// If the file was successfully created, then this returns true.
// Otherwise returns false.
bool isValid() {
return hfile_ != nullptr;
}
// The name of the file, mostly needed for debug logging.
const std::string& getName() {
return filename_;
}
virtual Status Append(const Slice& data) {
Log(mylog, "[hdfs] HdfsWritableFile Append %s\n", filename_.c_str());
const char* src = data.data();
size_t left = data.size();
size_t ret = hdfsWrite(fileSys_, hfile_, src, left);
Log(mylog, "[hdfs] HdfsWritableFile Appended %s\n", filename_.c_str());
if (ret != left) {
return IOError(filename_, errno);
}
return Status::OK();
}
virtual Status Flush() {
return Status::OK();
}
virtual Status Sync() {
Status s;
Log(mylog, "[hdfs] HdfsWritableFile Sync %s\n", filename_.c_str());
if (hdfsFlush(fileSys_, hfile_) == -1) {
return IOError(filename_, errno);
}
if (hdfsSync(fileSys_, hfile_) == -1) {
return IOError(filename_, errno);
}
Log(mylog, "[hdfs] HdfsWritableFile Synced %s\n", filename_.c_str());
return Status::OK();
}
// This is used by HdfsLogger to write data to the debug log file
virtual Status Append(const char* src, size_t size) {
if (hdfsWrite(fileSys_, hfile_, src, size) != (tSize)size) {
return IOError(filename_, errno);
}
return Status::OK();
}
virtual Status Close() {
Log(mylog, "[hdfs] HdfsWritableFile closing %s\n", filename_.c_str());
if (hdfsCloseFile(fileSys_, hfile_) != 0) {
return IOError(filename_, errno);
}
Log(mylog, "[hdfs] HdfsWritableFile closed %s\n", filename_.c_str());
hfile_ = nullptr;
return Status::OK();
}
};
// The object that implements the debug logs to reside in HDFS.
class HdfsLogger : public Logger {
private:
HdfsWritableFile* file_;
uint64_t (*gettid_)(); // Return the thread id for the current thread
public:
HdfsLogger(HdfsWritableFile* f, uint64_t (*gettid)())
: file_(f), gettid_(gettid) {
Log(mylog, "[hdfs] HdfsLogger opened %s\n",
file_->getName().c_str());
}
virtual ~HdfsLogger() {
Log(mylog, "[hdfs] HdfsLogger closed %s\n",
file_->getName().c_str());
delete file_;
if (mylog != nullptr && mylog == this) {
mylog = nullptr;
}
}
virtual void Logv(const char* format, va_list ap) {
const uint64_t thread_id = (*gettid_)();
// We try twice: the first time with a fixed-size stack allocated buffer,
// and the second time with a much larger dynamically allocated buffer.
char buffer[500];
for (int iter = 0; iter < 2; iter++) {
char* base;
int bufsize;
if (iter == 0) {
bufsize = sizeof(buffer);
base = buffer;
} else {
bufsize = 30000;
base = new char[bufsize];
}
char* p = base;
char* limit = base + bufsize;
struct timeval now_tv;
gettimeofday(&now_tv, nullptr);
const time_t seconds = now_tv.tv_sec;
struct tm t;
localtime_r(&seconds, &t);
p += snprintf(p, limit - p,
"%04d/%02d/%02d-%02d:%02d:%02d.%06d %llx ",
t.tm_year + 1900,
t.tm_mon + 1,
t.tm_mday,
t.tm_hour,
t.tm_min,
t.tm_sec,
static_cast<int>(now_tv.tv_usec),
static_cast<long long unsigned int>(thread_id));
// Print the message
if (p < limit) {
va_list backup_ap;
va_copy(backup_ap, ap);
p += vsnprintf(p, limit - p, format, backup_ap);
va_end(backup_ap);
}
// Truncate to available space if necessary
if (p >= limit) {
if (iter == 0) {
continue; // Try again with larger buffer
} else {
p = limit - 1;
}
}
// Add newline if necessary
if (p == base || p[-1] != '\n') {
*p++ = '\n';
}
assert(p <= limit);
file_->Append(base, p-base);
file_->Flush();
if (base != buffer) {
delete[] base;
}
break;
}
}
};
} // namespace
// Finally, the hdfs environment
// open a file for sequential reading
Status HdfsEnv::NewSequentialFile(const std::string& fname,
SequentialFile** result) {
HdfsReadableFile* f = new HdfsReadableFile(fileSys_, fname);
if (f == nullptr) {
*result = nullptr;
return IOError(fname, errno);
}
*result = dynamic_cast<SequentialFile*>(f);
return Status::OK();
}
// open a file for random reading
Status HdfsEnv::NewRandomAccessFile(const std::string& fname,
RandomAccessFile** result) {
HdfsReadableFile* f = new HdfsReadableFile(fileSys_, fname);
if (f == nullptr) {
*result = nullptr;
return IOError(fname, errno);
}
*result = dynamic_cast<RandomAccessFile*>(f);
return Status::OK();
}
// create a new file for writing
Status HdfsEnv::NewWritableFile(const std::string& fname,
WritableFile** result) {
Status s;
HdfsWritableFile* f = new HdfsWritableFile(fileSys_, fname);
if (f == nullptr || !f->isValid()) {
*result = nullptr;
return IOError(fname, errno);
}
*result = dynamic_cast<WritableFile*>(f);
return Status::OK();
}
Status HdfsEnv::NewRandomRWFile(const std::string& fname,
unique_ptr<RandomRWFile>* result,
const EnvOptions& options) {
return Status::NotSupported("NewRandomRWFile not supported on HdfsEnv");
}
bool HdfsEnv::FileExists(const std::string& fname) {
int value = hdfsExists(fileSys_, fname.c_str());
if (value == 0) {
return true;
}
return false;
}
Status HdfsEnv::GetChildren(const std::string& path,
std::vector<std::string>* result) {
int value = hdfsExists(fileSys_, path.c_str());
switch (value) {
case 0: {
int numEntries = 0;
hdfsFileInfo* pHdfsFileInfo = 0;
pHdfsFileInfo = hdfsListDirectory(fileSys_, path.c_str(), &numEntries);
if (numEntries >= 0) {
for(int i = 0; i < numEntries; i++) {
char* pathname = pHdfsFileInfo[i].mName;
char* filename = rindex(pathname, '/');
if (filename != nullptr) {
result->push_back(filename+1);
}
}
if (pHdfsFileInfo != nullptr) {
hdfsFreeFileInfo(pHdfsFileInfo, numEntries);
}
} else {
// numEntries < 0 indicates error
Log(mylog, "hdfsListDirectory call failed with error ");
throw HdfsFatalException("hdfsListDirectory call failed negative error.\n");
}
break;
}
case 1: // directory does not exist, exit
break;
default: // anything else should be an error
Log(mylog, "hdfsListDirectory call failed with error ");
throw HdfsFatalException("hdfsListDirectory call failed with error.\n");
}
return Status::OK();
}
Status HdfsEnv::DeleteFile(const std::string& fname) {
if (hdfsDelete(fileSys_, fname.c_str()) == 0) {
return Status::OK();
}
return IOError(fname, errno);
};
Status HdfsEnv::CreateDir(const std::string& name) {
if (hdfsCreateDirectory(fileSys_, name.c_str()) == 0) {
return Status::OK();
}
return IOError(name, errno);
};
Status HdfsEnv::CreateDirIfMissing(const std::string& name) {
const int value = hdfsExists(fileSys_, name.c_str());
// Not atomic. state might change b/w hdfsExists and CreateDir.
if (value == 0) {
return Status::OK();
} else {
return CreateDir(name);
}
};
Status HdfsEnv::DeleteDir(const std::string& name) {
return DeleteFile(name);
};
Status HdfsEnv::GetFileSize(const std::string& fname, uint64_t* size) {
*size = 0L;
hdfsFileInfo* pFileInfo = hdfsGetPathInfo(fileSys_, fname.c_str());
if (pFileInfo != nullptr) {
*size = pFileInfo->mSize;
hdfsFreeFileInfo(pFileInfo, 1);
return Status::OK();
}
return IOError(fname, errno);
}
Status HdfsEnv::GetFileModificationTime(const std::string& fname,
uint64_t* time) {
hdfsFileInfo* pFileInfo = hdfsGetPathInfo(fileSys_, fname.c_str());
if (pFileInfo != nullptr) {
*time = static_cast<uint64_t>(pFileInfo->mLastMod);
hdfsFreeFileInfo(pFileInfo, 1);
return Status::OK();
}
return IOError(fname, errno);
}
// The rename is not atomic. HDFS does not allow a renaming if the
// target already exists. So, we delete the target before attemting the
// rename.
Status HdfsEnv::RenameFile(const std::string& src, const std::string& target) {
hdfsDelete(fileSys_, target.c_str());
if (hdfsRename(fileSys_, src.c_str(), target.c_str()) == 0) {
return Status::OK();
}
return IOError(src, errno);
}
Status HdfsEnv::LockFile(const std::string& fname, FileLock** lock) {
// there isn's a very good way to atomically check and create
// a file via libhdfs
*lock = nullptr;
return Status::OK();
}
Status HdfsEnv::UnlockFile(FileLock* lock) {
return Status::OK();
}
Status HdfsEnv::NewLogger(const std::string& fname,
shared_ptr<Logger>* result) {
HdfsWritableFile* f = new HdfsWritableFile(fileSys_, fname);
if (f == nullptr || !f->isValid()) {
*result = nullptr;
return IOError(fname, errno);
}
HdfsLogger* h = new HdfsLogger(f, &HdfsEnv::gettid);
*result = h;
if (mylog == nullptr) {
// mylog = h; // uncomment this for detailed logging
}
return Status::OK();
}
} // namespace rocksdb
#endif // ROCKSDB_HDFS_FILE_C
#else // USE_HDFS
// dummy placeholders used when HDFS is not available
#include "rocksdb/env.h"
#include "hdfs/env_hdfs.h"
namespace rocksdb {
Status HdfsEnv::NewSequentialFile(const std::string& fname,
unique_ptr<SequentialFile>* result,
const EnvOptions& options) {
return Status::NotSupported("Not compiled with hdfs support");
}
}
#endif