Amos Kong 4fa862adf4 redis: skip processing request of EOF ...

When I test the redis cmd by echo and nc, there is a redundant error in the end.
I checked by strace, currently if client read nothing from stdin, it will
shutdown the socket, redis server will read nothing (0 byte) from socket. But
it tries to process the empty command and returns an error.

$ echo -n -e '*1\r\n$4\r\nping\r\n' |strace nc localhost 6379
| ...
|    read(0, "*1\r\n$4\r\nping\r\n", 8192)   = 14
|    select(5, [4], [4], [], NULL)           = 1 (out [4])
|>>> sendto(4, "*1\r\n$4\r\nping\r\n", 14, 0, NULL, 0) = 14
|    select(5, [0 4], [], [], NULL)          = 1 (in [0])
|    recvfrom(0, 0x7ffe4d5b6c70, 8192, 0, 0x7ffe4d5b6bf0, 0x7ffe4d5b6bec) = -1 ENOTSOCK (Socket operation on non-socket)
|    read(0, "", 8192)                       = 0
|>>> shutdown(4, SHUT_WR)                    = 0
|    select(5, [4], [], [], NULL)            = 1 (in [4])
|    recvfrom(4, "+PONG\r\n-ERR unknown command ''\r\n", 8192, 0, 0x7ffe4d5b6bf0, [0]) = 32
|    write(1, "+PONG\r\n-ERR unknown command ''\r\n", 32+PONG
|    -ERR unknown command ''
|    ) = 32
|    select(5, [4], [], [], NULL)            = 1 (in [4])
|    recvfrom(4, "", 8192, 0, 0x7ffe4d5b6bf0, [0]) = 0
|    close(1)                                = 0
|    close(4)                                = 0

Current result:
  $ echo -n -e '' |nc localhost 6379
  -ERR unknown command ''
  $ echo -n -e '*1\r\n$4\r\nping\r\n' |nc localhost 6379
  +PONG
  -ERR unknown command ''

Expected:
  $ echo -n -e '' |nc localhost 6379
  $ echo -n -e '*1\r\n$4\r\nping\r\n' |nc localhost 6379
  +PONG

Signed-off-by: Amos Kong <amos@scylladb.com>

2019-12-03 10:47:56 +08:00

3.2 KiB

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