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changing cf CLI trace stream from stdout to stderr
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Koper, Dies <diesk@...>
Hi friends,
Currently, the cf CLI trace when enabled ("CF_TRACE=true", `cf config -trace true` or with the `-v` option) is directed to stdout. Looking at other commands, e.g. `curl -v`, it's common to send such information to stderr. This recently came up in the following issue. https://github.com/cloudfoundry/cli/issues/962 I'd like to know whether anyone would be massively inconvenienced if we fixed this to make cf CLI trace output go to stderr (e.g. because you have many scripts expecting trace to be streamed to stdout, or not expecting anything but errors and warnings to be streamed to stderr)? Note that trace configured to output to a file would not be affected. Cheers, Dies Koper Cloud Foundry Product Manager - CLI |
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Hector Rivas Gandara
Hello,
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Have you tried sending CF_TRACE to /dev/stderr? Like this CF_TRACE=/dev/stderr cf apps | less I think it is system specific, but it should work on most of them. On 25 October 2016 at 04:44, Koper, Dies <diesk(a)fast.au.fujitsu.com> wrote:
Hi friends, --
Regards Hector Rivas | GDS / Multi-Cloud PaaS |
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Mike Youngstrom <youngm@...>
This change wouldn't effect any of my users.
Mike On Mon, Oct 24, 2016 at 9:44 PM, Koper, Dies <diesk(a)fast.au.fujitsu.com> wrote: Hi friends, |
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Koper, Dies <diesk@...>
Hi Hector,
I have not been able to find a way to make that work on Windows. CF_TRACE=/dev/stderr just creates a “dev” directory in the root of the drive you run cf from with a file called “stderr”. Regards, Dies Koper Cloud Foundry Product Manager - CLI From: Hector Rivas Gandara [mailto:hector.rivas.gandara(a)digital.cabinet-office.gov.uk] Sent: Tuesday, October 25, 2016 10:27 PM To: Discussions about Cloud Foundry projects and the system overall. Subject: [cf-dev] Re: changing cf CLI trace stream from stdout to stderr Hello, Have you tried sending CF_TRACE to /dev/stderr? Like this CF_TRACE=/dev/stderr cf apps | less I think it is system specific, but it should work on most of them. On 25 October 2016 at 04:44, Koper, Dies <diesk(a)fast.au.fujitsu.com<mailto:diesk(a)fast.au.fujitsu.com>> wrote: Hi friends, Currently, the cf CLI trace when enabled (“CF_TRACE=true”, `cf config –trace true` or with the `-v` option) is directed to stdout. Looking at other commands, e.g. `curl -v`, it’s common to send such information to stderr. This recently came up in the following issue. https://github.com/cloudfoundry/cli/issues/962 I’d like to know whether anyone would be massively inconvenienced if we fixed this to make cf CLI trace output go to stderr (e.g. because you have many scripts expecting trace to be streamed to stdout, or not expecting anything but errors and warnings to be streamed to stderr)? Note that trace configured to output to a file would not be affected. Cheers, Dies Koper Cloud Foundry Product Manager - CLI -- Regards Hector Rivas | GDS / Multi-Cloud PaaS |
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Daniel Mikusa
Just my $0.02, but I like the current behavior. I find it helpful for
troubleshooting purposes to be able to get the stream of HTTP messages inline with the output from the cli. It helps to very quickly and easily establish a timeline and isolate a particular HTTP request / response as being a problem, like when a response is slow. Just run `CF_TRACE=true cf ...` and watch to see where it pauses. I like the suggestion in the GH issue. Perhaps adding the option of specifying CF_TRACE=stderr (and stdout forconsistency, which would be equal to using 1) could be a way to do it. IMHO, if you did this then the default option would matter a lot less. I'd still prefer to keep the default behavior to STDOUT, but that's mostly me just being selfish. As long as I have a way to invoke that stdout behavior when I need it, I could live with the default changing. Dan On Tue, Oct 25, 2016 at 8:10 PM, Koper, Dies <diesk(a)fast.au.fujitsu.com> wrote: Hi Hector, |
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Stefan Mayr
Am 26.10.2016 um 02:10 schrieb Koper, Dies:
Hi Hector,I can't remember having a pseudo file for stderr in Windows. The OS provides default handles that can be used to write to stderr - no files. That's why you have os.Stderr in golang Maybe you could do the trick with named pipes and makepipe.exe included in MSSQL - tooling around pipes is very limited in windows. Regards, Stefan |
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Koper, Dies <diesk@...>
Hi Dan,
How would that experience be different if trace went to stderr? Wouldn’t the stream of HTTP messages display inline with the cli output in the same way? Regards, Dies Koper Cloud Foundry Product Manager - CLI From: Daniel Mikusa [mailto:dmikusa(a)pivotal.io] Sent: Wednesday, October 26, 2016 11:06 PM To: Discussions about Cloud Foundry projects and the system overall. Subject: [cf-dev] Re: Re: Re: changing cf CLI trace stream from stdout to stderr Just my $0.02, but I like the current behavior. I find it helpful for troubleshooting purposes to be able to get the stream of HTTP messages inline with the output from the cli. It helps to very quickly and easily establish a timeline and isolate a particular HTTP request / response as being a problem, like when a response is slow. Just run `CF_TRACE=true cf ...` and watch to see where it pauses. I like the suggestion in the GH issue. Perhaps adding the option of specifying CF_TRACE=stderr (and stdout for consistency, which would be equal to using 1) could be a way to do it.IMHO, if you did this then the default option would matter a lot less. I'd still prefer to keep the default behavior to STDOUT, but that's mostly me just being selfish. As long as I have a way to invoke that stdout behavior when I need it, I could live with the default changing. Dan On Tue, Oct 25, 2016 at 8:10 PM, Koper, Dies <diesk(a)fast.au.fujitsu.com<mailto:diesk(a)fast.au.fujitsu.com>> wrote: Hi Hector, I have not been able to find a way to make that work on Windows. CF_TRACE=/dev/stderr just creates a “dev” directory in the root of the drive you run cf from with a file called “stderr”. Regards, Dies Koper Cloud Foundry Product Manager - CLI From: Hector Rivas Gandara [mailto:hector.rivas.gandara(a)digital.cabinet-office.gov.uk<mailto:hector.rivas.gandara(a)digital.cabinet-office.gov.uk>] Sent: Tuesday, October 25, 2016 10:27 PM To: Discussions about Cloud Foundry projects and the system overall. Subject: [cf-dev] Re: changing cf CLI trace stream from stdout to stderr Hello, Have you tried sending CF_TRACE to /dev/stderr? Like this CF_TRACE=/dev/stderr cf apps | less I think it is system specific, but it should work on most of them. On 25 October 2016 at 04:44, Koper, Dies <diesk(a)fast.au.fujitsu.com<mailto:diesk(a)fast.au.fujitsu.com>> wrote: Hi friends, Currently, the cf CLI trace when enabled (“CF_TRACE=true”, `cf config –trace true` or with the `-v` option) is directed to stdout. Looking at other commands, e.g. `curl -v`, it’s common to send such information to stderr. This recently came up in the following issue. https://github.com/cloudfoundry/cli/issues/962 I’d like to know whether anyone would be massively inconvenienced if we fixed this to make cf CLI trace output go to stderr (e.g. because you have many scripts expecting trace to be streamed to stdout, or not expecting anything but errors and warnings to be streamed to stderr)? Note that trace configured to output to a file would not be affected. Cheers, Dies Koper Cloud Foundry Product Manager - CLI -- Regards Hector Rivas | GDS / Multi-Cloud PaaS |
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Daniel Mikusa
Sorry, I didn't explain that very well. Let me try again. In the simplest
case where you're watch it from a terminal / console, yes it would be the same. A few cases where this might be an issue: - bosh errand or CI system is running cf on your behalf and capturing the output. Display is often STDOUT / STDERR separate. - when troubleshooting with a user, it's easy to say run `CF_TRACE=true cf ... > full_output.txt`. I suppose this could be done with `CF_TRACE=true cf ... &> full_output.txt`, but I'm not sure what I'd do on a Windows system (without bash). Ultimately I just want something in the cli to get normal output mixed with trace output in the order things happen to build a timeline for troubleshooting purposes. It has always annoyed me a bit that `CF_TRACE=some-file.txt cf ...` doesn't do this (last time I looked, it just logs trace info, not cli output), but with the current behavior of the cli it's easy enough to workaround (redirect all to file). If the behavior changes, it wouldn't be the end of the world, but it would be slightly harder / more annoying to build the sequence of commands when troubleshooting. Hope that explains my concern a bit better. Thanks, Dan On Sun, Oct 30, 2016 at 4:37 AM, Koper, Dies <diesk(a)fast.au.fujitsu.com> wrote: Hi Dan, |
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Hector Rivas Gandara
Hi,
Sorry for the late response. Indeed the /dev/std{out,err} thing is implemented by the OS. I'm not a windows user by myself, but I read somewhere that bash emulates that. Can you try on bash. Also, you can play around with named pipes (which I don't know if it works on Windows). For instance: mkfifo /tmp/stderr # Create name pipe cat /tmp/stderr 1>&2 & # Read from that pipe and write in stderr CF_TRACE=/tmp/stderr cf apps # Run CF and send the trace output to the named pipe If you want ot mix the stdout and stderr, this hackery would work: cat /tmp/stderr | tee /tmp/cf_trace_combined.txt 1>&2 & # read the stderr fifo and write it to STDERR and to a file CF_TRACE=/tmp/stderr cf apps | tee /tmp/stderr # Write the cf STDOUT to the fifo If you change the `cat` to cat /tmp/stderr > /tmp/cf_trace_combined.txt & , you will get the combined output to that file. Anyway, yes, indeed, all this would be more easy if the application provides the feature itself. -- Regards Hector Rivas | GDS / Multi-Cloud PaaS |
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