GlideinWMS

File download is essential and it is tricky.

curl and wget have different versions behaving differently and many things can go wrong.
The functions in glidein_startup.sh need to be done more robust and modular, and maybe exported in glidein_lib.sh to be available to other scripts

Issues w/ current implementation:

• New problems come up periodically
• no debug messages (only warnings)
• some confusing messages, e.g.`wget_version=$(wget --version | head -1 )` may print "wget: command not found"
• wget/curl bits in fetch_file_base

Suggesting:

• perform_download: generic function invoking both, to be added, common parameters, error checking at the end, maybe consistent error messages
• perform_curl: all curl specific stuff should be here
• perform_wget: all wget specific stuff should be there

Example problem at RAL:

• glidein_startup from factory 3.6.2
• There is no wget, using curl "./glidein_startup.sh: line 1683: wget: command not found"
• File seems OK, has signature line in web browser: https://igwn-frontend.nautilus.optiputer.net/vofrontend/stage/description.k6pi5q.cfg
• Error: No signature in description file /pool/condor/dir_47254/glide_bHcUFG/client/description.k6pi5q.cfg.
• Arriving here means that curl completed w/o errors