- dd if=/dev/urandom of=test.file bs=1m count=100
- go build
- ./ test.file
This will have several goroutines try to read the file from the same file descriptor. And show that they all get only a random subset of the file.
Created
September 10, 2015 23:11
-
-
Save dragonfax/4a0da83b3bff3de791b6 to your computer and use it in GitHub Desktop.
test reading concurrently from the same io.Reader
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| ZiggyPiggy:concurrent_reader jstillwell$ ls -l test.file | |
| -rw-r--r-- 1 jstillwell staff 104857600 Sep 10 15:57 test.file | |
| ZiggyPiggy:concurrent_reader jstillwell$ go build && ./concurrent_reader test.file | |
| read 20973056 bytes | |
| read 16776704 bytes | |
| read 33553920 bytes | |
| read 33553920 bytes | |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| package main | |
| import ( | |
| "fmt" | |
| "io/ioutil" | |
| "os" | |
| "sync" | |
| ) | |
| func main() { | |
| filename := os.Args[1] | |
| file, err := os.Open(filename) | |
| if err != nil { | |
| panic(fmt.Sprintf("failure to open filename given on command line '%s'", filename)) | |
| } | |
| var wg sync.WaitGroup | |
| f := func() { | |
| defer wg.Done() | |
| buf, err := ioutil.ReadAll(file) | |
| if err != nil { | |
| panic(err) | |
| } | |
| fmt.Printf("read %d bytes\n", len(buf)) | |
| } | |
| for i := 0; i <= 3; i++ { | |
| wg.Add(1) | |
| go f() | |
| } | |
| wg.Wait() | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment