Central spider cache with optional module paths #783

I provide a "test" tree for modules that are not yet ready, perhaps need testing by some users to verify that it's ok before proceeding.

For this purpose i have a /apps/test vs /apps/prod. In each tree, I provide a central spider cache via

/apps/test/modules/cacheDir/...
/apps/prod/modules/cacheDir/...

Users have to opt in to using the test tree via module use /apps/test/modules/all.

I don't see any way of providing spider cache for both of these. or, even either one of them.

$ cat /etc/lmodrc.lua 
scDescriptT =  {
   {
      ["dir"]       = "/apps/test/modules/cacheDir/",
      ["timestamp"] = "/apps/test/modules/cacheTS.txt",
   },
   {
      ["dir"]       = "/apps/prod/modules/cacheDir/",
      ["timestamp"] = "/apps/prod/modules/cacheTS.txt",
   },

won't work as it just concatenates both caches. module spider isn't filtering on MODULEPATH at all.

I currently opted for a /etc/lmodrc.lua that just conditionally checks for each subdirectory

local function appendCacheForModulePath(mp)
   local cacheDir = mp .. "/../cacheDir"
   local timestampFile = mp .. "/../cacheTS.txt"

   table.insert(scDescriptT, {
      dir = cacheDir,
      timestamp = timestampFile,
   })
end

local modulePathList = os.getenv("MODULEPATH")
scDescriptT =  {}
if modulePathList then
   for mp in modulePathList:gmatch("[^:]+") do
      print(string.format("echo mp = %s", mp))
      appendCacheForModulePath(mp)
   end
end

but I'm also not sure if i simply reinventing some feature that already existed and i just missed.