data-transport/transport/nosql/mongodb.py

"""
Data Transport - 1.0
Steve L. Nyemba, The Phi Technology LLC

This file is a wrapper around mongodb for reading/writing content against a mongodb server and executing views (mapreduce)
"""
from pymongo        import MongoClient
import bson
from bson.objectid  import ObjectId
from bson.binary    import Binary
# import nujson as json
from datetime import datetime
import pandas as pd
import numpy as np
import gridfs
import sys
import json
import re
from multiprocessing import Lock, RLock
    """
    def __init__(self,**args):
        Mongo.__init__(self,**args)
    def read(self,**args):
        
        if 'mongo' in args or 'cmd' in args or 'pipeline' in args:
            #
            # @TODO:
            cmd = {}
            if 'aggregate' not in cmd and 'aggregate' not in args:
                cmd['aggregate'] = self.collection
            elif 'aggregate' in args :
                cmd['aggregate'] = args['aggregate']
            if 'pipeline' in args :
                cmd['pipeline']= args['pipeline']

            if 'pipeline' not in args or 'aggregate' not in cmd :
                cmd = args['mongo'] if 'mongo' in args else args['cmd']
            if "aggregate" in cmd :
                if "allowDiskUse" not in cmd :
                    cmd["allowDiskUse"] = True
                if "cursor" not in cmd :
                    cmd["cursor"] = {}
            r =  []
            out = self.db.command(cmd)
            #@TODO: consider using a yield (generator) works wonders
            while True :
                if 'values' in out :
                    r += out['values']
                if 'cursor' in out :
                    key = 'firstBatch' if 'firstBatch' in out['cursor'] else 'nextBatch'
                else:
                    key = 'n'
                if 'cursor' in out and out['cursor'][key] :
                    r += list(out['cursor'][key])
                elif key in out and out[key]:
                    r.append (out[key]) 
                    # yield out['cursor'][key]
                if key not in ['firstBatch','nextBatch'] or ('cursor' in out and out['cursor']['id']  == 0) :
                    break
                else:
                    out = self.db.command({"getMore":out['cursor']['id'],"collection":out['cursor']['ns'].split(".")[-1]}) 
                
                
            return pd.DataFrame(r)
        else:
            
            
            if 'table' in args  or 'collection' in args :
                if 'table' in args:
                    _uid = args['table']
                elif 'collection' in args :
                    _uid = args['collection']
                else:
                    _uid = self.collection 
            else:
                _uid = self.collection
            collection = self.db[_uid]                
            _filter = args['filter'] if 'filter' in args else {}
            _df =  pd.DataFrame(collection.find(_filter))
            columns = _df.columns.tolist()[1:]
            return _df[columns]
    def view(self,**args):
        """
        This function is designed to execute a view (map/reduce) operation
        """
        pass
class Writer(Mongo):
    """
    This class is designed to write to a mongodb collection within a database
    """
    def __init__(self,**args):
        Mongo.__init__(self,**args)
    def upload(self,**args) :
        """
        This function will upload a file to the current database (using GridFS)
        :param  data        binary stream/text to be stored
        :param  filename    filename to be used
        :param  encoding    content_encoding (default utf-8)
        
        """
        if 'encoding' not in args :
            args['encoding'] = 'utf-8'
        gfs = GridFS(self.db)
        gfs.put(**args)

    def archive(self):
        """
        This function will archive documents to the 
        """
        collection = self.db[self.collection]
        rows  = list(collection.find())
        for row in rows :
            if type(row['_id']) == ObjectId :
                row['_id'] = str(row['_id'])
        stream = Binary(json.dumps(collection,cls=IEncoder).encode())
        collection.delete_many({})
        now = "-".join([str(datetime.now().year()),str(datetime.now().month), str(datetime.now().day)])
        name = ".".join([self.collection,'archive',now])+".json"
        description = " ".join([self.collection,'archive',str(len(rows))])
        self.upload(filename=name,data=stream,description=description,content_type='application/json')
        # gfs = GridFS(self.db)
        # gfs.put(filename=name,description=description,data=stream,encoding='utf-8')
        # self.write({{"filename":name,"file":stream,"description":descriptions}})
        
            
        pass
    
    def write(self,info,**_args):
        """
        This function will write to a given collection i.e add a record to a collection (no updates)
        @param info new record in the collection to be added
        """
        # document  = self.db[self.collection].find()
        #collection = self.db[self.collection]
        # if type(info) == list :
        #     self.db[self.collection].insert_many(info)
        # else:
        try:
            if 'table' in _args or 'collection' in _args :
                _uid = _args['table'] if 'table' in _args else _args['collection']
            else:
                _uid = self.collection if 'doc' not in _args else _args['doc']
            if self._lock :
                Mongo.lock.acquire()
                info = json.loads(json.dumps(info))