Test lock types on various filesystems

locktest.ipynb

import os, fcntl
print("Lock test beginning.")
sep="\n---------\n"
print(sep)
home=os.getenv("HOME")
testfiles = [
    {"filepath": home + "/lockable.txt",
     "description": "writeable NFS via PV and local_lock=all"},
    {"filepath": "/tmp/lockable.txt",
     "description": "writeable local disk"},
    {"filepath": "/n" + home + "/lockable.txt",
     "description": "writeable NFS via direct pod specification with default NFS options"},
]

lock_calls = {"fcntl.flock": fcntl.flock,
              "fcntl.lockf": fcntl.lockf}
lock_sequence = [ fcntl.LOCK_SH, fcntl.LOCK_UN, fcntl.LOCK_EX, fcntl.LOCK_UN]
lock_desc = { fcntl.LOCK_SH: "shared lock",
             fcntl.LOCK_UN: "unlock",
             fcntl.LOCK_EX: "exclusive lock"}
modes = [ "w", "a", "w+", "a+", "r" ]
successes = []
failures = []
for entry in testfiles:
    filename = entry["filepath"]
    print("Testing file '{}' ({})".format(filename,entry["description"]))
    for lock in lock_calls:
        for mode in modes:
            for cmd in lock_sequence:
                cn=lock_desc[cmd]
                desc = "{} '{}' ('{}') via {}()".format(cn,filename, mode, lock)
                
                print("    About to request {}".format(desc),end="")
                try:
                    fd = open(filename,mode)
                    desc = "{} '{}' ('{}') via {}()".format(cn,filename, mode, lock)
                    lock_calls[lock](fd,cmd)
                    print("success.")
                    successes.append(desc)
                except Exception as exc:
                    print("failure: {}".format(exc))
                    failures.append("{}: {}".format(desc,exc))
print(sep)
print("Successes:\n\n{}".format("\n".join(successes)))
print(sep)
print("Failures:\n\n{}".format("\n".join(failures)))
print(sep)
print("Lock test complete.")