pandoc document conversion failed with error 127

Question

I'm not sure how to make a reproducible example of this, but I'm curious to hear if anyone else has encountered this problem. I have an R Markdown file hosted via shiny server on an EC2 instance running Ubuntu. Everything was working fine for days and now suddenly I get the following error when I try to view the document in the browser:

pandoc document conversion failed with error 127

I'm not converting to pdf, haven't pushed any changes, and it was working a few hours ago. I'm not finding much of anything online about this error code so I have no idea how to debug this issue. Anyone had this happen before?

Answer 1

I faced a similar issue today (see below from .log file):

Warning in system(command) : system call failed: Cannot allocate memory
Warning: Error in : pandoc document conversion failed with error 127
Stack trace (innermost first):
    105: pandoc_convert
    104: convert
    103: render
    102: discover_rmd_resources
    101: find_external_resources
    100: copy_render_intermediates
     99: output_format$intermediates_generator
     98: <Anonymous>
     97: do.call
     96: contextFunc
     95: .getReactiveEnvironment()$runWith
     94: shiny::maskReactiveContext
     93: <reactive>
     82: doc
     81: shiny::renderUI
     80: func
     79: origRenderFunc
     78: output$__reactivedoc__
      3: <Anonymous>
      2: do.call
      1: rmarkdown::run

I too am running Shiny Server via Ubuntu on an EC2 instance, specifically t2.micro. I solved this issue by following the top-voted answer here: How do you add swap to an EC2 instance?

sudo /bin/dd if=/dev/zero of=/var/swap.1 bs=1M count=1024
sudo /sbin/mkswap /var/swap.1
sudo chmod 600 /var/swap.1
sudo /sbin/swapon /var/swap.1

Add to /etc/fstab:

/var/swap.1   swap    swap    defaults        0   0

In short, you can create swap (memory) space on your EBS (since t2.micro instances don't have ephemeral storage) and this should alleviate your memory issue (without having to move up to a larger EC2 instance).