[jira] [Commented] (MESOS-4576) Introduce a stout helper for "which"

[Joseph Wu (JIRA)]

    [ 
https://issues.apache.org/jira/browse/MESOS-4576?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15127107#comment-15127107
 ] 

Joseph Wu commented on MESOS-4576:
----------------------------------

I think the usage for the {{sha512}} case would be multiple calls to 
{{os::which}}.  
i.e. Something not-too-pretty like: 
{code}
Option<string> whichSha = os::which("shasum");

if (whichSha.isNone()) {
  whichSha = os::which("sha512sum");

  if (whichSha.isNone()) {
     whichSha = os::which("openssl");

     if (whichSha.isNone()) {
        return Error("...");
     }
  }
}
{code}

> Introduce a stout helper for "which"
> ------------------------------------
>
>                 Key: MESOS-4576
>                 URL: https://issues.apache.org/jira/browse/MESOS-4576
>             Project: Mesos
>          Issue Type: Improvement
>          Components: stout
>            Reporter: Joseph Wu
>              Labels: mesosphere
>
> We may want to add a helper to {{stout/os.hpp}} that will natively emulate 
> the functionality of the Linux utility {{which}}.  i.e.
> {code}
> Option<string> which(const string& command)
> {
>   Option<string> path = os::getenv("PATH");
>   // Loop through path and return the first one which os::exists(...).
>   return None();
> }
> {code}
> This helper may be useful:
> * for test filters in {{src/tests/environment.cpp}}
> * a few tests in {{src/tests/containerizer/port_mapping_tests.cpp}}
> * the {{sha512}} utility in {{src/common/command_utils.cpp}}
> * as runtime checks in the {{LogrotateContainerLogger}}
> * etc.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)