overwrite information on redis using redis_om (python)

Question

I am using redis_OM in order to make it easier to do aggregations using redisearch module. The thing is that I want to upload some data to redis everyday without keeping the one uploaded the day before, that is to say, I want either to make the old data expire or overwrite it with the new one.

I am doing it with the example of the Redis documentation and redis cloud. This is my model:

import datetime
from typing import Optional
from pydantic import EmailStr
from redis_om import HashModel


class Customer(HashModel):
    first_name: str
    last_name: str
    email: EmailStr
    join_date: datetime.date
    age: int
    bio: Optional[str]

This is how I upload the data:

import csv

import os
os.environ["REDIS_OM_URL"]="redis://default:TbmcFFUUjPiOakJA5RcZKV1DBNRRFV9L@redis-18508.c228.us-central1-1.gce.cloud.redislabs.com:18508/test"

from customer_model import Customer
from redis_om import Migrator

with open('customers.csv') as csv_file:
    customers = csv.DictReader(csv_file)

    for customer in customers:
        cus = Customer(**customer)

        print(f"{customer['firstName']} -> {cus.pk}")
        cus.save()

# Create a RediSearch index
Migrator().run()

I know that we can make the data expire in redis using EXPIRE key seconds. But how do I make expire a whole model?

Can I somehow overwrite it? I don't think this second option is posible as each object is linked to a pk that is unique.

Thanks!

Simon Prickett · Accepted Answer · 2022-03-14 18:44:57Z

3

If you want to expire a Customer object, you can do this with the expire method by getting the underlying redis-py connection for your Customer model. Here's an example:

from redis_om import HashModel, Migrator

# Define a customer model
class Customer(HashModel):
    first_name: str
    last_name: str
    age: int
    bio: str

# Create some customers
cust1 = Customer(
    first_name="Customer",
    last_name="One",
    age=38,
    bio="This is some text about customer 1"
)

cust2 = Customer(
    first_name="Customer",
    last_name="Two",
    age=38,
    bio="This is some text about customer 2"
)

# Persist customers to Redis, setting expiry to 60 seconds
cust1.save()
print(f"Expiring {cust1.key()}")
Customer.db().expire(cust1.key(), 60)
cust2.save()
print(f"Expiring {cust2.key()}")
Customer.db().expire(cust2.key(), 60)

# Create index
Migrator().run()

Showing the expiry set in Redis:

$ redis-cli
127.0.0.1:6379> ttl :__main__.Customer:01FY4VVCW081EHDH6S5W6JY9FD
(integer) 52
127.0.0.1:6379> ttl :__main__.Customer:01FY4VVCW133PPMVXH6HNERKXE
(integer) 46

answered Mar 14, 2022 at 18:44

Simon Prickett

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2 Comments

Yassine Nacif Over a year ago

If at the connection, you specify a db index different from 0, the Migration().run() will fail, with an error, saying:

redis_om.model.migrations.migrator.MigrationError: Creating search indexes is only supported in database 0. You attempted to create an index in database 2

Simon Prickett Over a year ago

Search functionalithy isn't supported in databases other than database 0. Using numbered databases and the SELECT command is not generally considered a good idea.

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