How I started using odmantic

[aahnik]

I am an 18 yo beginner developer from India. I am building a "refer and earn" telegram bot for my friend. (currently a private project, but plan to open source it sometime in future)

I find it more natural and to think in terms of python objects. Pydantic is just awesome as it does everything so elegantly.

For rapid prototyping, I had just used an in-memory python dictionary with the user id as key, and the Person model as the value.

Previously my code was something like this in storage.py

from typing import Any, Dict, List, Optional, Union

from pydantic import BaseModel

class Person(BaseModel):
    uid: int
    referer: Optional[int] = None
    joined: StrictBool = False
    referals: Optional[List[int]] = []
    coins: int = 0
    wallet: str = ""


stored: Dict[int, Person] = {}

In other modules to access or manipulate the data, I did something like this

from myproject import storage as st

# create a new person
st.stored[some_id] = st.Person(uid=some_id)

# get an existing person
person = st.stored.get(some_id)

# update existing person
person.coins = 1
st.stored[person.uid] = person

---

What I did was working, but I needed two things

• Persistence
• Scalability

I did not like the idea of using SQL, as I would be rapidly changing the structure of data in the future. I had never used MongoDB at this point. But I thought let me give it a shot. (I don't know much of theoretical stuff, just exploring!) Another reason I did not use SQL is that I found SQLAlchemy a little scary.

While I was searching the web and exploring GitHub, I found the magic wand! odmantic.

Odmantic made it absolutely easy for me to switch from my rough prototype to a serious and powerful MongoDB database.

Switching to odmantic was easy.

- from pydantic import BaseModel
+ from odmantic import AIOEngine, Field, Model

- class Person(BaseModel):
+ class Person(Model):

-    uid: int
+    uid: int = Field(primary_field=True)

- stored: Dict[int, Person] = {}
+ engine: AIOEngine = None

At the entry point where I started my bot client, I also initialized my AIOEngine

# bot.py
from myproject import storage as st

engine = AIOEngine()
st.engine = engine

Now in other modules to access or manipulate the data, I simply do like this.

from myproject import storage as st

# create a new person
- st.stored[some_id] = st.Person(uid=some_id)
+ person = st.Person(uid=some_id)
+ await st.engine.save(person)

# get an existing person
- person = st.stored.get(some_id)
+  person: st.Person = await st.engine.find_one(
+            st.Person, st.Person.uid == some_id
 +       )

# update existing person
person.coins = 1
- st.stored[person.uid] = person
+ await st.engine.save(person)

From now on I think I will be using MongoDB with odmantic for my future projects. It's much easy to define the data structure, and everything is fast and fully scalable.

Thanks, @art049 for creating odmantic!

As of June 26th, 2021, the bot has nearly 5K users and everything seems to be working fine. I also did schema changes by adding new attributes to the Person model. As I had set a default value for the new fields, there was no issue.

Anyone reading this feel free to suggest improvements or comment about your experiences.

[chrisdewa]

I agree! odmantic is truly fantastic! I use it mostly for discord bots and it's a breeze.
I might as well make a show and tell later :)