pandoc version 1.12.3 or higher is required and was not found (R shiny)

Question

I have a problem generating a pdf report from my app shiny which is hosted on a server.

the app works fine but when I press the button to download the report, I get

Answer 1

I had a similar problem with pandoc on Debian 10 while building a bookdown document. In the Makefile what I did was:

# use rstudio pandoc
# this rule sets the PANDOC environment variable from the shell
build_book1:
    export RSTUDIO_PANDOC="/usr/lib/rstudio/bin/pandoc";\
    Rscript -e 'bookdown::render_book("index.Rmd", "bookdown::gitbook")'

# use rstudio pandoc
# this rule sets the environment variable from R using multilines
build_book2:
    Rscript -e "\
    Sys.setenv(RSTUDIO_PANDOC='/usr/lib/rstudio/bin/pandoc');\
    bookdown::render_book('index.Rmd', 'bookdown::gitbook')"

These two rules are equivalent and knit the book successfully.

I just didn't like the long Rscript command:

Rscript -e "Sys.setenv(RSTUDIO_PANDOC='/usr/lib/rstudio/bin/pandoc'); bookdown::render_book('index.Rmd', 'bookdown::gitbook')"