Resource leak in select chapter: HTTP response bodies not closed #888
Description
While running the Racer example from the select chapter, I noticed a connection/file descriptor leak.
Each call to http.Get in measureResponseTime and ping opens a connection that isn't closed:
func measureResponseTime(url string) time.Duration {
start := time.Now()
http.Get(url) // Response body is never closed
return time.Since(start)
}I wrote a test to count open file descriptors before and after calling Racer multiple times:
go test -v
=== RUN TestRacerLeaksFDs
racer_leak_test.go:29: FDs before: 18
racer_leak_test.go:36: FDs after: 218
racer_leak_test.go:39: LEAKED: 200 file descriptors
--- FAIL: TestRacerLeaksFDs (0.06s)
FAIL
exit status 1
FAIL temp 0.074sAdding a defer resp.Body.Close() after a successful http.Get call resolves the leak:
func measureResponseTime(url string) time.Duration {
start := time.Now()
resp, err := http.Get(url)
if err == nil {
defer resp.Body.Close()
}
return time.Since(start)
}go test -v
=== RUN TestRacerLeaksFDs
racer_leak_test.go:29: FDs before: 18
racer_leak_test.go:36: FDs after: 18
--- PASS: TestRacerLeaksFDs (0.04s)
PASS
ok temp 0.048s