14807: Add comments to "error indicates success" code.

[arvados.git] / services / crunch-run / crunchrun.go

diff --git a/services/crunch-run/crunchrun.go b/services/crunch-run/crunchrun.go
index 2b9a119581dfd7c4f3245b1e57317ae95155f5b9..0576337aa13c280841187db3a7aea2dcf4af65c0 100644 (file)
--- a/services/crunch-run/crunchrun.go
+++ b/services/crunch-run/crunchrun.go
@@ -1737,6 +1737,7 @@ func main() {
        cgroupParentSubsystem := flag.String("cgroup-parent-subsystem", "", "use current cgroup for given subsystem as parent cgroup for container")
        caCertsPath := flag.String("ca-certs", "", "Path to TLS root certificates")
        detach := flag.Bool("detach", false, "Detach from parent process and run in the background")
+       stdinEnv := flag.Bool("stdin-env", false, "Load environment variables from JSON message on stdin")
        sleep := flag.Duration("sleep", 0, "Delay before starting (testing use only)")
        kill := flag.Int("kill", -1, "Send signal to an existing crunch-run process for given UUID")
        list := flag.Bool("list", false, "List UUIDs of existing crunch-run processes")
@@ -1766,6 +1767,13 @@ func main() {
 
        flag.Parse()
 
+       if *stdinEnv && !ignoreDetachFlag {
+               // Load env vars on stdin if asked (but not in a
+               // detached child process, in which case stdin is
+               // /dev/null).
+               loadEnv(os.Stdin)
+       }
+
        switch {
        case *detach && !ignoreDetachFlag:
                os.Exit(Detach(flag.Arg(0), os.Args, os.Stdout, os.Stderr))
@@ -1856,3 +1864,21 @@ func main() {
                log.Fatalf("%s: %v", containerId, runerr)
        }
 }
+
+func loadEnv(rdr io.Reader) {
+       buf, err := ioutil.ReadAll(rdr)
+       if err != nil {
+               log.Fatalf("read stdin: %s", err)
+       }
+       var env map[string]string
+       err = json.Unmarshal(buf, &env)
+       if err != nil {
+               log.Fatalf("decode stdin: %s", err)
+       }
+       for k, v := range env {
+               err = os.Setenv(k, v)
+               if err != nil {
+                       log.Fatalf("setenv(%q): %s", k, err)
+               }
+       }
+}