Python MongoDB programming
MongoDB through outgoing connections - inserting, finding, updating and aggregating documents with pymongo.
Create an outgoing MongoDB connection in Dashboard and everything that MongoDB offers will be available to your services via the underlying pymongo library, as in the examples below.
Creating a connection
In Dashboard, go to Connections -> NoSQL -> MongoDB and click Create a new outgoing MongoDB connection.
Fill in the form:
- Name - any name of your choice
- Server list - one
host:portentry per line, e.g. a singlelocalhost:27017line or several lines when connecting to a replica set - Username and password - credentials to authenticate with, the auth source defaults to
admin - Replica set - optional, the name of the replica set to require
The TLS section lets you connect to servers that require encrypted connections - turn the TLS checkbox on and point the CA certificates file to the PEM certificate of the authority that signed the server's certificate. For mutual TLS, add a combined client certificate and private key PEM file too.
After the connection is created, click Ping to confirm that Zato can reach the server.
Inserting documents
In your services, look up the connection by name with self.mongodb - what you get back is a pymongo client, so databases and collections are accessed the way pymongo does it.
# -*- coding: utf-8 -*-
# Zato
from zato.server.service import Service
class MyService(Service):
def handle(self):
# Get a client by the connection's name
conn = self.mongodb['My MongoDB Connection']
# Pick a database and a collection
db = conn['my_database']
orders = db['orders']
# Insert a document
result = orders.insert_one({'order_id': 123, 'status': 'ready'})
self.logger.info('Inserted: %s', result.inserted_id)
Finding documents
# -*- coding: utf-8 -*-
# Zato
from zato.server.service import Service
class MyService(Service):
def handle(self):
conn = self.mongodb['My MongoDB Connection']
orders = conn['my_database']['orders']
# Find one document
order = orders.find_one({'order_id': 123})
self.logger.info('Order: %s', order)
# Find all documents matching a query
for item in orders.find({'status': 'ready'}):
self.logger.info('Ready: %s', item)
Updating and deleting
# -*- coding: utf-8 -*-
# Zato
from zato.server.service import Service
class MyService(Service):
def handle(self):
conn = self.mongodb['My MongoDB Connection']
orders = conn['my_database']['orders']
# Update a document
orders.update_one({'order_id': 123}, {'$set': {'status': 'shipped'}})
# Delete a document
orders.delete_one({'order_id': 123})
Aggregations
The full aggregation pipeline is available too.
# -*- coding: utf-8 -*-
# Zato
from zato.server.service import Service
class MyService(Service):
def handle(self):
conn = self.mongodb['My MongoDB Connection']
orders = conn['my_database']['orders']
# Count orders per status
pipeline = [
{'$group': {'_id': '$status', 'count': {'$sum': 1}}},
{'$sort': {'count': -1}},
]
for row in orders.aggregate(pipeline):
self.logger.info('%s: %s', row['_id'], row['count'])
Pinging from a service
# -*- coding: utf-8 -*-
# Zato
from zato.server.service import Service
class MyService(Service):
def handle(self):
conn = self.mongodb['My MongoDB Connection']
# The same command that the Dashboard's Ping link runs
conn.admin.command('ping')
self.logger.info('MongoDB is reachable')
Testing with a local server
To test your connections without an existing MongoDB installation, one command starts a complete server in Docker:
docker run -d --rm --name zato-mongodb -e MONGO_INITDB_ROOT_USERNAME=zato -e MONGO_INITDB_ROOT_PASSWORD=zato -p 27017:27017 mongo:8
In Dashboard, create an outgoing MongoDB connection with localhost:27017 in the server list, username and password both set to zato, and click Ping to confirm that Zato can reach the server.
When you are done, the container removes itself on stop: