separate temp files for each worker

Project.toml

@@ -4,11 +4,12 @@ authors = ["Andreas Scheidegger <[email protected]> and contributors"
 version = "0.3.1"
 
 [deps]
+Distributed = "8ba89e20-285c-5b6f-9357-94700520ee1b"
 Poppler_jll = "9c32591e-4766-534b-9725-b71a8799265b"
 
 [compat]
-julia = "1.6"
 Poppler_jll = "23"
+julia = "1.6"
 
 [extras]
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"

README.md

@@ -54,3 +54,5 @@ be deleted.
 All the heavy lifting is done by
 [`Poppler`](https://poppler.freedesktop.org/). Thanks to the maintainers
 of `Poppler` and [`Poppler_jll.jl`](https://github.com/JuliaBinaryWrappers/Poppler_jll.jl)!
+
+Thanks to @zauster for implementing separate temp files for each worker.

src/PDFmerger.jl

@@ -2,6 +2,7 @@ module PDFmerger
 
 import Base.Filesystem
 using Poppler_jll: pdfunite, pdfinfo, pdfseparate
+using Distributed: myid
 
 export merge_pdfs, split_pdf, append_pdf!
 
@@ -33,16 +34,19 @@ function merge_pdfs(files::Vector{T}, destination::AbstractString="merged.pdf";
     # See: https://gitlab.freedesktop.org/poppler/poppler/-/issues/334
     filemax = 200
 
+    # Get the id of the current process/worker, such that separate workers
+    # create separate temporary files and do not mess up files of other workers.
+    procid = myid()
     k = 1
     for files_part in Base.Iterators.partition(files, filemax)
         if k == 1
-            outfile_tmp2 = "_temp_destination_$k"
+            outfile_tmp2 = "_temp_destination_$(procid)_$k"
 
             run(`$(pdfunite()) $files_part $outfile_tmp2`)
 
         else
-            outfile_tmp1 = "_temp_destination_$(k-1)"
-            outfile_tmp2 = "_temp_destination_$k"
+            outfile_tmp1 = "_temp_destination_$(procid)_$(k-1)"
+            outfile_tmp2 = "_temp_destination_$(procid)_$k"
 
             run(`$(pdfunite()) $outfile_tmp1 $files_part $outfile_tmp2`)
 
@@ -51,12 +55,12 @@ function merge_pdfs(files::Vector{T}, destination::AbstractString="merged.pdf";
     end
 
     # rename last file
-Filesystem.mv("_temp_destination_$(k-1)", destination, force=true)
+    Filesystem.mv("_temp_destination_$(procid)_$(k-1)", destination, force=true)
 
-# remove temp files
-Filesystem.rm(destination * "_x_", force=true)
-Filesystem.rm.("_temp_destination_$(i)" for i in 1:(k-2))
-if cleanup
+    # remove temp files
+    Filesystem.rm(destination * "_x_", force=true)
+    Filesystem.rm.("_temp_destination_$(procid)_$(i)" for i in 1:(k-2))
+    if cleanup
         Filesystem.rm.(files, force=true)
     end