SourceNamespaces.py

import json
from pprint import pprint

from pymongo import MongoClient


class SourceNamespaces:
    """
    SourceNamespaces class which takes a URI or SRV Connection string as an argument
    """

    def __init__(self, connection_string):
        """
        Create the class object
        """
        self.client = MongoClient(connection_string)
        self.namespaces = self._get_namespaces()

    def _get_namespaces(self):
        """Initializes the namespace dictionary with the source namespaces and calls GenGetCollections()
        to add a nested dictionary of specific collstats and index shapes

        Arguments:
        self
        """
        namespaces = {}
        for db in self.client.database_names():
            if db not in ('admin', 'local', 'config'):
                for coll in self.gen_get_collections(db):
                    namespaces.update(coll)
        return namespaces

    def gen_get_DBstats(self, db):
        """
        Retrieves the dbstats at KB resolution from the provide MongoDB instance(s)

        Arguments:
        self
        db -- string, database name
        """
        yield self.client[db].command('dbstats', scale=1024)

    def gen_get_collections(self, db):
        """
        Generator yields the statistics and index definitions at KB scale from the provided database to be added
        to the namespace dictionary on a per collection basis

        Arguments:
        self
        db -- string, database name
        """
        for coll in self.client[db].collection_names():
            data = self.client[db].command('collstats', coll, scale=1024)
            target = {
                data.get('ns'): {
                    'count': data.get('count'),
                    'size': data.get('size'),
                    'avgObjSize': data.get('avgObjSize'),
                    'capped': data.get('capped'),
                    'nindexes': data.get('nindexes'),
                    'totalIndexSize': data.get('totalIndexSize'),
                    'indexSizes': data.get('indexSizes'),
                    'indexes': self.get_indexes(db, coll)
                }
            }
            yield target

    def get_indexes(self, db, coll):
        """
        Gathers index structure for a particular namespace into a dictionary

        Arguments:
        self
        db -- string, database name
        coll -- string collection name
        """
        return self.client[db][coll].index_information()

    def print_namespaces(self):
        """
        Prints the namespaces dictionary

        Arguments:
        self
        """
        pprint(self.namespaces)