paulgorman.org

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Thu Feb 1 09:37:47 EST 2018 Slept from eleven to seven without waking. High of thirty-eight and partly cloudy, but temperatures fall throughout the day. Work: - Docker notes Done. https://paulgorman.org/technical/docker.txt - Work on MECS Done. - 3:30 PM call with Bullseye and AT&T regarding fiber Done. https://www.tucny.com/telephony/asterisk-rpms https://fedoraproject.org/wiki/How_to_create_an_RPM_package Adding storage of recent log entries in MECS, I played with Go's circular list type: // cirlist plays with Go's circular list container. package main import ( "container/ring" "fmt" ) func main() { r := ring.New(3) for i := 0; i < 10; i++ { r = r.Next() r.Value = i fmt.Println(r.Value) } fmt.Println("---") for i := 0; i < r.Len(); i++ { r = r.Next() fmt.Println(r.Value) } } Twenty-minute walk at lunch. Sunny and not too cold. Windy. The complexity of Docker put me off it for a long time, but it might be OK. It's certainly more robust than systemd-nspawn. Much more of a real competitor to LXC (though, I admit, the battle seems lost for LXC). Home: - Play with ring containers in Go Done. Raspberry Pi variants: http://www.friendlyarm.com/index.php?route=product/category&path=69 > Boustrophedon is a Greek word meaning “in the manner of an ox,” and scripts written in it move like an ox plowing a field, reversing direction with each line. https://hub.docker.com/_/busybox/ The fact that Busybox includes runit could be quite useful in a Docker container. [EDIT: the following is significantly improved in tomorrow's entry.] // ringlog uses Go's ring container to keep the latest log entries. package main // Multiple runs will show that the ringLogger goroutine does not guarantee // the exact order of entries. In a non-trivial use, make the ring size // large enough to catch all the interesting recent entries. import ( "container/ring" "fmt" "log" ) var errCount int = -1 var errCh chan error = make(chan error, 3) var errRing = ring.New(5) func getTestError() error { errCount++ return fmt.Errorf("test error %v", errCount) } func ringLogger() { for e := range errCh { log.Println(e) errRing.Value = e errRing = errRing.Next() } close(errCh) } func main() { go ringLogger() for i := 0; i < 10; i++ { err := getTestError() if err != nil { errCh <- err } // Uncomment (and import "time") to see how output regularizes: // time.Sleep(time.Millisecond * 100) } for i := 0; i < errRing.Len(); i++ { fmt.Println("Reprint of", errRing.Value) errRing = errRing.Next() } } Lunch: coffee, falafel bowl Dinner: pizza

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