def copyFromDFS(address, fname, path):
""" Contact the metadata server to ask for the file blocks of
the file fname. Get the data blocks from the data nodes.
Saves the data in path.
"""
# Contact the metadata server to ask for information of fname
# Create socket and connect to metadata server
metaSock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
metaSock.connect(address)
# Create get packet and send request to metadata server
p = Packet()
p.BuildGetPacket(fname)
metaSock.sendall(p.getEncodedPacket())
# Recieve chunk list
msg = b""
while True:
buffer = metaSock.recv(2048)
msg += buffer
if getsizeof(buffer) < 2048:
break
# If file not found, exit, if file found, decode packet
if msg != b"NFOUND":
p.DecodePacket(msg)
else:
exit("File not found, exiting...")
# If there is no error response Retreive the data blocks
# Get blocks
blocks = p.getDataNodes()
# Open file
fd = open(path, "wb+")
for ip, addr, blockId in blocks:
# Create socket and connect to node
nodeSock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
nodeSock.connect((ip, addr))
# Build packet and send request to data node
p.BuildGetDataBlockPacket(blockId)
nodeSock.send(p.getEncodedPacket())
# Recieve block and write to file named path
fd.write(nodeSock.recv(16384))
# Close socket
nodeSock.close()
def handle(self):
# Establish a connection with the local database
db = mds_db("dfs.db")
db.Connect()
# Define a packet object to decode packet messages
p = Packet()
# Receive a msg from the list, data-node, or copy clients
msg = b""
while True:
buffer = self.request.recv(2048)
msg += buffer
if getsizeof(buffer) < 2048:
break
print(msg, type(msg))
# Decode the packet received
try:
p.DecodePacket(msg)
except:
print("Error in recieved packet")
# Extract the command part of the received packet
cmd = p.getCommand()
# Invoke the proper action
if cmd == "reg":
# Registration client
self.handle_reg(db, p)
elif cmd == "list":
self.handle_list(db)
elif cmd == "put":
# Client asking for servers to put data
# Fill code
self.handle_put(db, p)
elif cmd == "get":
# Client asking for servers to get data
# Fill code
self.handle_get(db, p)
elif cmd == "dblks":
# Client sending data blocks for file
# Fill code
self.handle_blocks(db, p)
db.Close()
def handle(self):
# Recieve packet
msg = b""
while True:
buffer = self.request.recv(4096)
msg += buffer
if getsizeof(buffer) < 4096:
break
print(msg, type(msg))
# Parse message as Packet
p = Packet()
p.DecodePacket(msg)
# Run command in p
cmd = p.getCommand()
if cmd == "put":
self.handle_put(p)
elif cmd == "get":
self.handle_get(p)
