Server-wrapper

Protocol

A client-to-server message is structured as follows.

 __________________________________________________________
| | | | | |
| type | name_length | name | payload_length | payload |
| (1 byte) | (4 bytes) | | (4 bytes) | |
|__________|_____________|______|________________|_________|

A server-to-client message is structured as follows.

 _____________________________________
| | | |
| type | payload_length | payload |
| (1 byte) | (4 bytes) | |
|__________|________________|_________|

These are the messages:

type	description	direction
00	Alive?	c -> s
08	ACK	s -> c
09	NACK	s -> c
10	Regular parameter	c -> s
20	Input file parameter	c -> s
30	Output file parameter	c -> s
40	Run request	c -> s
50	Get output	c -> s
59	Output	s -> c

Use-case scenario

Preliminaries

• Start server on port 9001 only allowing for 1 concurrent run request that executes the command /ufs/elkebir/src/heinz/build/heinz.

   ./server.py 9001 1 /ufs/elkebir/src/heinz/build/heinz
  

• Start client that connects to localhost via port 9001.

   ./testclient localhost 9001
  

Client-server session

1. Do a ping.

    > 0
   8
   

The server responds with ACK (8).

2. Send over regular parameter -p.

    > 10 -p
   8
   

The server responds with ACK (8).

3. Send over regular parameter -t 5.

    > 10 -t 5
   8
   

The server responds with ACK (8).

4. Send over input file parameter -n <FILE>.

    > 20 -n /ufs/elkebir/src/NINA/data/MWCS/test/nodes-from-russia.txt
   8
   

   The server responds with ACK (8) and generated a new file in the specified /tmp directory. The contents of this file correspond to nodes-from-russia.txt.

5. Send over input file parameter -e <FILE>.

    > 20 -e /ufs/elkebir/src/NINA/data/MWCS/test/edges-from-russia.txt
   8
   

   The server responds with ACK (8) and generated a new file in the specified /tmp directory. The contents of this file correspond to edges-from-russia.txt.

6. Send over output file parameter -o.

    > 30 -o
   8
   

   The server responds with ACK (8) and generated a new parameter -o <NEW_OUT_FILE> where <NEW_OUT_FILE> is a new unique file name.

7. Tell the server to run the executable.

    > 40
   8
   

Upon completion, the server responds with ACK (8).

8. Obtain stderr.

    > 50 255
   59 ...
   

The server responds with message 59 containing stderr.

9. Obtain stdout.

    > 50 254
   59 ...
   

The server responds with message 59 containing stdout.

10. Obtain first output file (numbered 0).

    > 50 0
    59 ...
    

The server responds with message 59 containing the output.

11. Obtain second output file (numbered 1).

    50 1 9

Since we did not specify a second output file parameter, the server responds with NACK (9).

12. Close the connection.

    > x
    

The server will remove all generated files.