The number server listed in this repository receives numbers and logs them into a log file
(the path can be defined on start). A termination keyword can be set on start of the script. The server
will use that as a signal for a graceful shutdown attempt.
By default, the server will start in port 4000, will write to the ./numbers.log file,
will take numbers up to 999999999 and will recreate the log file per fresh restart.
The server is limited to take up to 5 concurrent connections (although, this can be changed on start, also).
The server will prompt statistics to STDOUT every 10 seconds (by default, this interval can be changed also):
Example output (every 10 seconds):
Starting number server. Welcome!
Received 492203 unique numbers, 1969333 duplicates (Total processed: 2461536). Unique totals: 492203
Received 640896 unique numbers, 2566315 duplicates (Total processed: 3207211). Unique totals: 1133099
Received 636761 unique numbers, 2551738 duplicates (Total processed: 3188499). Unique totals: 1769860
Received 638486 unique numbers, 2560362 duplicates (Total processed: 3198848). Unique totals: 2408346
Received 619657 unique numbers, 2487099 duplicates (Total processed: 3106756). Unique totals: 3028003
It's written in Go.
go version go1.14.2 or above.
First, clone this repository:
git clone git@github.com:mountolive/numberserver.git
Build the project:
go build
This will create the script that would start the server, it should have execution permissions:
./numberserver, or ./numberserver.exe for windows.
The script allows for some initial customization of the parameters which the server should use.
For a detailed list of the parameters, you can run ./numberserver --help (./numberserver.exe --help on windows). This will prompt the following:
NAME:
Number logger - Writes numbers to defined log file.
Numbers can have up to the max number
of digits defined by the user: 9 by default.
When the termination ("terminate") keyword is prompted,
the program will attempt to shutdown gracefully.
This termination keyword can be changed on start (see --help)
USAGE:
numberserver [global options] command [command options] [arguments...]
COMMANDS:
help, h Shows a list of commands or help for one command
GLOBAL OPTIONS:
--port value, -p value Port to be listened to (default: 4000)
--append, -a Whether to append to existing log file or recreate on start
--logfile value, -l value Log file's path where the inputs would be written (default: "./numbers.log")
--termination value, -t value Terminate keyword, for shutting down the server (default: "terminate")
--digits value, -d value Max number of digits permitted for int input (max: 9) (default: 9)
--interval value, -i value Show statistics every * seconds (default: 10)
--maxconn value, -c value Max number of concurrent connections allowed (default: 5)
--help, -h
Tests can be executed with go test or, even better, go test --race (this detects possible race conditions, check here).
In terms of actual execution, the following client could be of help for testing the results of the script:
package main
import (
"fmt"
"math/rand"
"net"
"strings"
"time"
)
func main() {
conn, err := net.Dial("tcp", "localhost:4000")
defer conn.Close()
if err != nil {
fmt.Printf("%v \n", err)
return
}
createRandomNum := func() string {
num := rand.Intn(999999999)
stringRep := fmt.Sprintf("%d", num)
stringLength := len(stringRep)
leadingZeroes := 9 - stringLength
if leadingZeroes > 0 {
stringRep = strings.Repeat("0", leadingZeroes) + stringRep
}
return stringRep + "\n"
}
timeout := time.After(time.Second * 60)
for {
select {
case <-timeout:
fmt.Println("Exiting")
return
default:
conn.Write([]byte(createRandomNum()))
}
}
}
- Each input from a client ends in a carriage character (new-line)
- On shutdown, it's possible that the last few messages received won't be written to the log file. (When the global context is canceled, the first routine receiving the signal will close the file.)