parameter: the three parameters are

March 12, 2021 · View on GitHub

Get a CBDClient object that interacts with the Curve cluster

import curvefs

# Get a CBDClient object that interacts with the back-end cluster. Different CBDClient objects can establish connections with different clusters
cbd1 = curvefs.CBDClient()
cbd2 = curvefs.CBDClient()

CBDClient initialization

import curvefs
cbd = curvefs.CBDClient()
  
# parameter: full path of curve-client configuration file
# return: return 0 if initialized successfully, -1 means failed
cbd.Init("/etc/curve/client.conf")

Create file

import curvefs
cbd = curvefs.CBDClient()
cbd.Init("/etc/curve/client.conf")  # subsequent examples omit the initialization process
 
# parameter: the three parameters are
#      file full path
#      user information
#      file size
# return: return 0 if create successfully, otherwise return an error code

# First initialize user information (the control plane interfaces of curvefs have user information verification, and user information needs to be passed in)
user = curvefs.UserInfo_t()
user.owner = "curve"
user.password = ""  # when the password is empty, it can be omitted

# Create a file with Create interface
cbd.Create("/curve", user, 10*1024*1024*1024)
  
# UserInfo definition
typedef struct UserInfo {
    char owner[256];       # username 
    char password[256];    # password
} UserInfo_t;

Get file information

# parameter: the three parameters are
#      filename
#      user information
#      fileInfo[exit parameter]
# return: return 0 if get successfully, otherwise return an error code

# Construct user information
user = curvefs.UserInfo_t()
user.owner = "curve"

# Construct file information
finfo = curvefs.FileInfo_t()

# Get file information
cbd.StatFile("/curve", user, finfo)
print finfo.filetype
print finfo.length
print finfo.ctime
  
# FileInfo definition
typedef struct FileInfo {
    uint64_t      id;          
    uint64_t      parentid;
    int           filetype;   # volume type
    uint64_t      length;     # volume size
    uint64_t      ctime;      # volume create time
    char          filename[256];   # volume name
    char          owner[256];      # volume owner
    int           fileStatus;      # volume status
} FileInfo_t;
 
# File status
#define CURVE_FILE_CREATED            0
#define CURVE_FILE_DELETING           1
#define CURVE_FILE_CLONING            2
#define CURVE_FILE_CLONEMETAINSTALLED 3
#define CURVE_FILE_CLONED             4
#define CURVE_FILE_BEINGCLONED        5

Extend file

# parameter: the three parameters are
#      filename
#      user information
#      file size after extend
# return: return 0 if extend successfully, otherwise return an error code

# Construct user information
user = curvefs.UserInfo_t()
user.owner = "curve"

# Extend
cbd.Extend("/curve", user, 20*1024*1024*1024)

# Get file information after extension
finfo = curvefs.FileInfo_t()
cbd.StatFile("/curve", user, finfo)
print finfo.length

Open/Close file

# Open file
# parameter: the two parameters are
#      filename
#      user information
# return: return fd if open successfully, otherwise return error code

# Construct user information
user = curvefs.UserInfo_t()
user.owner = "user1"

# Open file，return fd
fd = cbd.Open("/tmp1", user)
  
# Close file
# parameter: fd returned when opening the file
# return: return 0 if closed successfully, otherwise return an error code
cbd.Close(fd)

Read and write file

# Write file
# parameter: the four parameters are
#      fd
#      data to write
#      offset
#      date length
# return: return the number of bytes written If write successful, otherwise return an error code

# Construct user information
user = curvefs.UserInfo_t()
user.owner = "user1"

# Open file，return fd
fd = cbd.Open("/tmp1", user)

# Write files (Currently, 4k alignment is required for reading and writing)
cbd.Write(fd, "aaaaaaaa"*512, 0, 4096)
cbd.Write(fd, "bbbbbbbb"*512, 4096, 4096)
  
# Read file
# parameter: the four parameters are
#      fd
#      null string
#      offset
#      data length to read
# return: return read data if read successfully, otherwise return an error code

# The read content is returned by the return value, buf is not needed, you can pass in an empty string
cbd.Read(fd，"", 0, 4096)

# Close file
cbd.Close(fd)

Note: The current python api does not support asynchronous reading and writing

Delete file

# parameter: the two parameters are
#      filename
#      user information
# return: return 0 if delete successfully, otherwise return an error code

# Construct user information
user = curvefs.UserInfo_t()
user.owner = "curve"

# Delete file
cbd.Unlink("/curve", user)

Recover file

# parameter: the three parameters are
#      filename
#      user information
#      file id (optional, default is 0)
# return: return 0 if recover successfully, otherwise return an error code

# Construct user information
user = curvefs.UserInfo_t()
user.owner = "curve"

# Recover file
cbd.Recover("/curve", user, 0)

Rename file

# parameter: the three parameters are
#      user information
#      old filename
#      new filename
# return: return 0 if rename successfully,  otherwise return an error code

# Construct user information
user = curvefs.UserInfo_t()
user.owner = "curve"

# Rename
cbd.Rename(user, "/curve", "/curve-new")

Create a directory

# parameter: the two parameters are
#      directory path
#      user information
# return: return 0 if create successfully,  otherwise return an error code

# Construct user information
user = curvefs.UserInfo_t()
user.owner = "curve"
# Create directory
cbd.Mkdir("/curvedir", user)

Delete directory

# parameter: the two parameters are
#      directory path
#      user information
# return: return 0 if create successfully,  otherwise return an error code
  
# Construct user information
user = curvefs.UserInfo_t()
user.owner = "curve"

# Delete directory
cbd.Rmdir("/curvedir", user)

List the files in the directory

# parameter: the two parameters are
#      directory path
#      user information
# return: files in the directory (only filename)
files = cbd.Listdir("/test", user)
for f in files:
    print f

Get the cluster ID

# Determine whether this get is successful by the return value
# success: return cluster ID
# fail: return null string
clusterId = cbd.GetClusterId()
print clusterId
# c355675a-f4d2-4729-b80a-5a7bcc749d1c

Clean CBDClient object

cbd.UnInit()

Error code

Code	Message	description
0	OK	success
-1	EXISTS	file or directory exists
-2	FAILED	fail
-3	DISABLEDIO	disable io
-4	AUTHFAIL	authentication failed
-5	DELETING	deleting
-6	NOTEXIST	file not exist
-7	UNDER_SNAPSHOT	under snapshot
-8	NOT_UNDERSNAPSHOT	not under snapshot
-9	DELETE_ERROR	delete error
-10	NOT_ALLOCATE	segment not allocated
-11	NOT_SUPPORT	operation not supported
-12	NOT_EMPTY	directory not empty
-13	NO_SHRINK_BIGGER_FILE	no shrinkage
-14	SESSION_NOTEXISTS	session not exist
-15	FILE_OCCUPIED	file occupied
-16	PARAM_ERROR	parameter error
-17	INTERNAL_ERROR	internal error
-18	CRC_ERROR	CRC error
-19	INVALID_REQUEST	parameter invalid
-20	DISK_FAIL	disk fail
-21	NO_SPACE	no space
-22	NOT_ALIGNED	io not aligned
-23	BAD_FD	file is being closed, fd unavailable
-24	LENGTH_NOT_SUPPORT	file length is not supported
-25	SESSION_NOT_EXIST	session not exist, duplicate with -14
-26	STATUS_NOT_MATCH	status error
-27	DELETE_BEING_CLONED	delete the file being cloned
-28	CLIENT_NOT_SUPPORT_SNAPSHOT	this version of client not support snapshot
-29	SNAPSHOT_FROZEN	snapshot is disabled
-100	UNKNOWN	unknown error