RIFT OSM R1 Initial Submission

[osm/SO.git] / rwlaunchpad / plugins / rwnsm / rift / tasklets / rwnsmtasklet / config_value_pool.py

diff --git a/rwlaunchpad/plugins/rwnsm/rift/tasklets/rwnsmtasklet/config_value_pool.py b/rwlaunchpad/plugins/rwnsm/rift/tasklets/rwnsmtasklet/config_value_pool.py
new file mode 100644 (file)
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--- /dev/null
+++ b/rwlaunchpad/plugins/rwnsm/rift/tasklets/rwnsmtasklet/config_value_pool.py
@@ -0,0 +1,154 @@
+
+# 
+#   Copyright 2016 RIFT.IO Inc
+#
+#   Licensed under the Apache License, Version 2.0 (the "License");
+#   you may not use this file except in compliance with the License.
+#   You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS,
+#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#   See the License for the specific language governing permissions and
+#   limitations under the License.
+#
+
+import os
+import pickle
+import uuid
+
+
+class ParameterValueError(Exception):
+    pass
+
+
+class ParameterValuePool(object):
+    def __init__(self, log, name, value_iter):
+        self._log = log
+        self._name = name
+
+        self._used_pool_values = []
+        self._available_pool_values = list(value_iter)
+
+        self._backing_filepath = os.path.join(
+                os.environ["RIFT_ARTIFACTS"],
+                "parameter_pools",
+                self._name
+                )
+
+        self._read_used_pool_values()
+
+    def _save_used_pool_values(self):
+        dir_path = os.path.dirname(self._backing_filepath)
+        if not os.path.exists(dir_path):
+            try:
+                os.makedirs(dir_path, exist_ok=True)
+            except OSError as e:
+                self._log.error("Could not create directory for save used pool: %s", str(e))
+
+        try:
+            with open(self._backing_filepath, "wb") as hdl:
+                pickle.dump(self._used_pool_values, hdl)
+        except OSError as e:
+            self._log.error(
+                    "Could not open the parameter value pool file: %s",
+                    str(e))
+        except pickle.PickleError as e:
+            self._log.error(
+                    "Could not pickle the used parameter value pool: %s",
+                    str(e))
+
+    def _read_used_pool_values(self):
+        try:
+            with open(self._backing_filepath, 'rb') as hdl:
+                self._used_pool_values = pickle.load(hdl)
+
+        except (OSError, EOFError):
+            self._log.warning("Could not read from backing file: %s",
+                              self._backing_filepath)
+            self._used_pool_values = []
+
+        except pickle.PickleError as e:
+            self._log.warning("Could not unpickle the used parameter value pool from %s: %s",
+                              self._backing_filepath, str(e))
+            self._used_pool_values = []
+
+        for value in self._used_pool_values:
+            self._available_pool_values.remove(value)
+
+    def get_next_unused_value(self):
+        if len(self._available_pool_values) == 0:
+            raise ParameterValueError("Not more parameter values to to allocate")
+
+        next_value = self._available_pool_values[0]
+        self._log.debug("Got next value for parameter pool %s: %s", self._name, next_value)
+
+        return next_value
+
+    def add_used_value(self, value):
+        value = int(value)
+
+        if len(self._available_pool_values) == 0:
+            raise ParameterValueError("Not more parameter values to to allocate")
+
+        if value in self._used_pool_values:
+            raise ParameterValueError(
+                    "Primitive value of {} was already used for pool name: {}".format(
+                        value,
+                        self._name,
+                        )
+                    )
+
+        if value != self._available_pool_values[0]:
+            raise ParameterValueError("Parameter value not the next in the available list: %s", value)
+
+        self._available_pool_values.pop(0)
+        self._used_pool_values.append(value)
+        self._save_used_pool_values()
+
+    def remove_used_value(self, value):
+        if value not in self._used_pool_values:
+            self._log.warning("Primitive value of %s was never allocated for pool name: %s",
+                    value, self._name
+                    )
+            return
+
+        self._used_pool_values.remove(value)
+        self._available_pool_values.insert(0, value)
+        self._save_used_pool_values()
+
+
+if __name__ == "__main__":
+    import logging
+    logging.basicConfig(level=logging.DEBUG)
+    logger = logging.getLogger("config_value_pool.py")
+    name = str(uuid.uuid4())
+    param_pool = ParameterValuePool(logger, name, range(1000, 2000))
+
+    a = param_pool.get_next_unused_value()
+    assert a == 1000
+
+    param_pool.add_used_value(a)
+
+    a = param_pool.get_next_unused_value()
+    assert a == 1001
+    param_pool.add_used_value(a)
+
+    param_pool = ParameterValuePool(logger, name, range(1000, 2000))
+    a = param_pool.get_next_unused_value()
+    assert a == 1002
+
+    try:
+        param_pool.add_used_value(1004)
+    except ParameterValueError:
+        pass
+    else:
+        assert False
+
+    a = param_pool.get_next_unused_value()
+    assert a == 1002
+    param_pool.add_used_value(1002)
+
+    param_pool = ParameterValuePool(logger, name, range(1005, 2000))