CODEWITHSUNDEEP
rshinyshiny-server
Steven
Steven

Reputation: 3292

Shiny Server R sessions creates a tempdir() it doesn't have permission to access

I have a Shiny app that works as expected both locally and when containerized. The app receives some user input, queries a database, and returns a .zip containing a .pdf and .xlsx file. Because reasons, I will be deploying it to a server running Shiny Server. When running the app, I get an error that processing the [filename].knit.md is impossible because "Permission denied:"

enter image description here

After digging into why this might be the case, I think it's a function of the user shiny (running the app in shiny-server.conf) doesn't have permissions to access the dir/file. The trouble I'm having is diagnosing this error because the temp dir and file don't appear to exist anywhere in the local directory structure.

In server.R, I call tempfile() and use that temporary file as the input for output_file in the render() command. I know that tempfile() is a subdirectory of the per-session temporary directory so how can I ensure that user shiny can access any tempdir() created during app operation?

Further, am I assuming correctly that the temp dir in the image above is automatically deleted when the app errors out? I can't find that dir anywhere in the /tmp tree of the server.

Upvotes: 2

Views: 1448

Answers (1)

Phil
Phil

Reputation: 1179

In the doc of tempdir()

By default, tmpdir will be the directory given by tempdir(). This will be a subdirectory of the per-session temporary directory found by the following rule when the R session is started. The environment variables TMPDIR, TMP and TEMP are checked in turn and the first found which points to a writable directory is used: if none succeeds ‘/tmp’ is used. The path should not contain spaces. Note that setting any of these environment variables in the R session has no effect on tempdir(): the per-session temporary directory is created before the interpreter is started.

So

mkdir mydir
export TMPDIR=mydir
Rscript -e "tempfile();tempdir();"

give

[1] "mydir/RtmphR2Rkx/file19da392dac5546"
[1] "mydir/RtmphR2Rkx"

Else give the right to /tmp

Upvotes: 2

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