Merge pull request #499 from fermitools/init_scitokens_cache_loc

move scitokens cache to /tmp

lib/fake_ifdh.py

@@ -41,6 +41,49 @@
 DEFAULT_ROLE = "Analysis"
 
 
+def init_scitokens() -> None:
+    """
+    So the scitokens library by default puts a sqlite database
+    in $HOME/.cache/scitokens; which is a problem when your
+    home area is in NFS, as sqlite doesn't like sharing files
+    over NFS.  So to tell it to use something different
+    we have to make a config file which points the cache area
+    somewhere local.
+    So we make a subdirectory in /tmp (or $TMPDIR)
+    and put the config file in there, which tells scitokens
+    to put the cache file in there as well.
+    """
+    uid = os.getuid()
+    tdir = os.environ.get("TMPDIR", "/tmp")
+    jstmpdir = f"{tdir}/js_scitok_{uid}"
+    cfgfile = f"{jstmpdir}/.scitokens.cfg"
+
+    # make sure we have the directory
+    if not os.access(jstmpdir, os.W_OK):
+        os.makedirs(jstmpdir)
+
+    # always update the config file, so /tmp scrubbers do not delete it
+    # out from under us
+    if os.access(cfgfile, os.W_OK):
+        os.utime(cfgfile)
+    else:
+        with open(cfgfile, "w") as cff:
+            cff.write(f"[scitokens]\ncache_location: {jstmpdir}\n")
+
+    # in case moving it to /tmp doesn't fix the bug, check for zero length cache file
+    # and remove it if zero length
+    cachefile = f"{jstmpdir}/scitokens/scitokens_keycache.sqllite"
+    if os.access(cachefile, os.R_OK):
+        si = os.stat(f"{jstmpdir}/scitokens/scitokens_keycache.sqllite")
+        if si.st_size == 0:
+            os.unlink(cachefile)
+
+    scitokens.set_config(cfgfile)
+
+
+init_scitokens()
+
+
 def getTmp() -> str:
     """return temp directory path"""
     return os.environ.get("TMPDIR", "/tmp")