The communication protocol of FastDFS is TCP/IP, the package composes of header and body which may be empty.
header format:
@ TRACKER_PROTO_PKG_LEN_SIZE bytes package length
@ 1 byte command
@ 1 byte status
note:
# TRACKER_PROTO_PKG_LEN_SIZE (8) bytes number buff is Big-Endian bytes
body format:
1. common command(普通命令)
* FDFS_PROTO_CMD_QUIT（终止连接）
# function: notify server connection will be closed
# request body: none (no body part)
# response: none (no header and no body)
2. storage server to tracker server command（SS与TS 间的命令）
* the reponse command is TRACKER_PROTO_CMD_STORAGE_RESP
* TRACKER_PROTO_CMD_STORAGE_JOIN（SS加入TS）
# function: storage join to tracker
# request body:
@ FDFS_GROUP_NAME_MAX_LEN + 1 bytes: group name
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: storage port
# response body: n * (1 + FDFS_IPADDR_SIZE) bytes, n >= 0. One storage entry format:
@ 1 byte: storage server status
@ FDFS_IPADDR_SIZE bytes: storage server ip address
# memo: return all storage servers in the group only when storage servers changed or return none
* TRACKER_PROTO_CMD_STORAGE_BEAT（SS向TS发送heart beat）
# function: heart beat
# request body: none or storage stat info
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: total upload count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: success upload count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: total set metadata count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: success set metadata count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: total delete count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: success delete count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: total download count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: success download count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: total get metadata count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: success get metadata count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: last source update timestamp
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: last sync update timestamp
# response body: same to command TRACKER_PROTO_CMD_STORAGE_JOIN
# memo: storage server sync it's stat info to tracker server only when storage stat info changed
* TRACKER_PROTO_CMD_STORAGE_REPORT（报告磁盘使用情况）
# function: report disk usage
# request body:
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: total space in MB
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: free space in MB
# response body: same to command TRACKER_PROTO_CMD_STORAGE_JOIN
* TRACKER_PROTO_CMD_STORAGE_REPLICA_CHG（复制新加入的SS）
# function: replica new storage servers which maybe not exist in the tracker server
# request body: n * (1 + FDFS_IPADDR_SIZE) bytes, n >= 1. One storage entry format:
@ 1 byte: storage server status
@ FDFS_IPADDR_SIZE bytes: storage server ip address
# response body: none
* TRACKER_PROTO_CMD_STORAGE_SYNC_SRC_REQ（当加入新的SS时，同步SS）
# function: source
storage require sync. when add a new storage server, the existed
storage servers in the same group will ask the tracker server to tell
the source storage server which will sync old data to it
# request body:
@ FDFS_IPADDR_SIZE bytes: dest storage server (new storage server) ip address
# response body: none or
@ FDFS_IPADDR_SIZE bytes: source storage server ip address
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: sync until timestamp
# memo: if the dest storage server not do need sync from one of storage servers in the group, the response body is emtpy
* TRACKER_PROTO_CMD_STORAGE_SYNC_DEST_REQ（新加入的SS请求同步）
# function: dest storage server (new storage server) require sync
# request body: none
# response body: none or
@ FDFS_IPADDR_SIZE bytes: source storage server ip address
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: sync until timestamp
# memo: if the dest storage server not do need sync from one of storage servers in the group, the response body is emtpy
* TRACKER_PROTO_CMD_STORAGE_SYNC_NOTIFY（新加入的SS同步通知）
# function: new storage server sync notify
# request body:
@ FDFS_IPADDR_SIZE bytes: source storage server ip address
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: sync until timestamp
# response body: same to command TRACKER_PROTO_CMD_STORAGE_JOIN
3. client to tracker server command（Client与TS之间的命令）
* the reponse command of following 2 commands is TRACKER_PROTO_CMD_SERVER_RESP
* TRACKER_PROTO_CMD_SERVER_LIST_GROUP（列出所有的组）
# function: list all groups
# request body: none
# response body: n group entries, n >= 0, the format of each entry:
@ FDFS_GROUP_NAME_MAX_LEN+1 bytes: group name
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: free disk storage in MB
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: storage server count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: storage server port
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: active server count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: current write server index
* TRACKER_PROTO_CMD_SERVER_LIST_STORAGE（列出一个组的SS信息）
# function: list storage servers of a group
# request body:
@ FDFS_GROUP_NAME_MAX_LEN bytes: the group name to query
# response body: n storage entries, n >= 0, the format of each entry:
@ 1 byte: status
@ FDFS_IPADDR_SIZE byte: ip address
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: total space in MB
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: free space in MB
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: total upload count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: success upload count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: total set metadata count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: success set metadata count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: total delete count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: success delete count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: total download count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: success download count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: total get metadata count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: success get metadata count
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: last source update timestamp
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: last sync update timestamp
* the reponse command of following 2 commands is TRACKER_PROTO_CMD_SERVICE_RESP
* TRACKER_PROTO_CMD_SERVICE_QUERY_STORE（询问让哪个SS存储文件）
# function: query which storage server to store file
# request body: none
# response body:
@ FDFS_GROUP_NAME_MAX_LEN bytes: group name
@ FDFS_IPADDR_SIZE - 1 bytes: storage server ip address
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: storage server port
* TRACKER_PROTO_CMD_SERVICE_QUERY_FETCH（询问从哪个SS下载文件）
# function: query which storage server to download the file
# request body:
@ FDFS_GROUP_NAME_MAX_LEN bytes: group name
@ filename bytes: filename
# response body:
@ FDFS_GROUP_NAME_MAX_LEN bytes: group name
@ FDFS_IPADDR_SIZE - 1 bytes: storage server ip address
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: storage server port
4. storage server to storage server command（SS之间的命令）
* the reponse command is STORAGE_PROTO_CMD_RESP
* STORAGE_PROTO_CMD_SYNC_CREATE_FILE（同步新创建的文件）
# function: sync new created file
# request body:
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: filename bytes
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: file size/bytes
@ FDFS_GROUP_NAME_MAX_LEN bytes: group name
@ filename bytes : filename
@ file size bytes: file content
# response body: none
* STORAGE_PROTO_CMD_SYNC_DELETE_FILE（同步被删除的文件）
# function: sync deleted file
# request body:
@ FDFS_GROUP_NAME_MAX_LEN bytes: group name
@ filename bytes: filename
# response body: none
* STORAGE_PROTO_CMD_SYNC_UPDATE_FILE（同步被更新的文件）
# function: sync updated file
# request body: same to command STORAGE_PROTO_CMD_SYNC_CREATE_FILE
# respose body: none
5. client to storage server command（Client与SS之间的命令）
* the reponse command is STORAGE_PROTO_CMD_RESP
* STORAGE_PROTO_CMD_UPLOAD_FILE（向SS上传文件）
# function: upload file to storage server
# request body:
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: meta data bytes
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: file size
@ meta data bytes: each meta data seperated by \x01,
name and value seperated by \x02
@ file size bytes: file content
# response body:
@ FDFS_GROUP_NAME_MAX_LEN bytes: group name
@ filename bytes: filename
* STORAGE_PROTO_CMD_DELETE_FILE（从SS删除文件）
# function: delete file from storage server
# request body:
@ FDFS_GROUP_NAME_MAX_LEN bytes: group name
@ filename bytes: filename
# response body: none
* STORAGE_PROTO_CMD_SET_METADATA（从SS删除metadata）
# function: delete file from storage server
# request body:
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: filename length
@ TRACKER_PROTO_PKG_LEN_SIZE bytes: meta data size
@ 1 bytes: operation flag,
'O' for overwrite all old metadata
'M' for merge, insert when the meta item not exist, otherwise update it
@ FDFS_GROUP_NAME_MAX_LEN bytes: group name
@ filename bytes: filename
@ meta data bytes: each meta data seperated by \x01,
name and value seperated by \x02
# response body: none
* STORAGE_PROTO_CMD_DOWNLOAD_FILE（从SS下载文件）
# function: download/fetch file from storage server
# request body:
@ FDFS_GROUP_NAME_MAX_LEN bytes: group name
@ filename bytes: filename
# response body:
@ file content
* STORAGE_PROTO_CMD_GET_METADATA（从SS获得metadata）
# function: get metat data from storage server
# request body:
@ FDFS_GROUP_NAME_MAX_LEN bytes: group name
@ filename bytes: filename
# response body
@ meta data buff, each meta data seperated by \x01, name and value seperated by \x02