+logger = logging.getLogger('arvados.cwl-runner')
+
+class CollectionCache(object):
+ def __init__(self, api_client, keep_client, num_retries,
+ cap=256*1024*1024,
+ min_entries=2):
+ self.api_client = api_client
+ self.keep_client = keep_client
+ self.num_retries = num_retries
+ self.collections = OrderedDict()
+ self.lock = threading.Lock()
+ self.total = 0
+ self.cap = cap
+ self.min_entries = min_entries
+
+ def cap_cache(self):
+ if self.total > self.cap:
+ # ordered list iterates from oldest to newest
+ for pdh, v in self.collections.items():
+ if self.total < self.cap or len(self.collections) < self.min_entries:
+ break
+ # cut it loose
+ logger.debug("Evicting collection reader %s from cache", pdh)
+ del self.collections[pdh]
+ self.total -= v[1]
+
+ def get(self, pdh):
+ with self.lock:
+ if pdh not in self.collections:
+ logger.debug("Creating collection reader for %s", pdh)
+ cr = arvados.collection.CollectionReader(pdh, api_client=self.api_client,
+ keep_client=self.keep_client,
+ num_retries=self.num_retries)
+ sz = len(cr.manifest_text()) * 128
+ self.collections[pdh] = (cr, sz)
+ self.total += sz
+ self.cap_cache()
+ else:
+ cr, sz = self.collections[pdh]
+ # bump it to the back
+ del self.collections[pdh]
+ self.collections[pdh] = (cr, sz)
+ return cr
+
+