Hello Family

HelloFamily is a simple application that registers a list of people info into a persistent collection identified by an alias. Every time this application is executed, it first tries to load the collection by its alias, and if it does not exist the application creates it. Once the collection has been retrieved, or created, the given new person info is added to the collection and the whole set of people is displayed.

Note

This example is available in GitHub.

Class definition:

family.py

from dataclay import DataClayObject, activemethod


class Person(DataClayObject):

    name: str
    age: int

    @activemethod
    def __init__(self, name, age):
        self.name = name
        self.age = age


class Family(DataClayObject):

    members: list[Person]

    @activemethod
    def __init__(self, *args):
        self.members = list(args)

    @activemethod
    def add(self, new_member: Person):
        self.members.append(new_member)

    @activemethod
    def __str__(self) -> str:
        result = ["Members:"]

        for p in self.members:
            result.append(" - Name: %s, age: %d" % (p.name, p.age))

        return "\n".join(result)

Then we can deploy dataclay using docker-compose. Create a file docker-compose.yml and use the following docker-compose file using docker-compose up:

docker-compose.yml

services:

  redis:
    image: redis:latest
    ports:
      - 6379:6379

  metadata-service:
    image: "ghcr.io/bsc-dom/dataclay:edge"
    depends_on:
      - redis
    ports:
      - 16587:16587
    environment:
      - DATACLAY_KV_HOST=redis
      - DATACLAY_KV_PORT=6379
      - DATACLAY_ID
      - DATACLAY_PASSWORD=s3cret
      - DATACLAY_USERNAME=testuser
      - DATACLAY_DATASET=testdata
      - DATACLAY_METADATA_PORT=16587
      - DATACLAY_LOGLEVEL=DEBUG
    command: python -m dataclay.metadata

  backend:
    image: "ghcr.io/bsc-dom/dataclay:edge"
    depends_on:
      - redis
    ports:
      - 6867:6867
    environment:
      - DATACLAY_KV_HOST=redis
      - DATACLAY_KV_PORT=6379
      - DATACLAY_BACKEND_ID
      - DATACLAY_BACKEND_NAME
      - DATACLAY_BACKEND_PORT=6867
      - DATACLAY_LOGLEVEL=DEBUG
    command: python -m dataclay.backend
    volumes:
      - ./model:/workdir/model:ro

Then we can run the classes in the application:

client.py

from model.family import Family, Person

from dataclay import Client

# DC_HOST should be pass as environment variable
client = Client(host="127.0.0.1", username="testuser", password="s3cret", dataset="testdata")
client.start()

print("Hello1")

try:
    family = Family.get_by_alias("myfamily2")
except Exception:
    family = Family()
    family.make_persistent(alias="myfamily2")

person = Person("Marc", 24)
family.add(person)
print("Hello2")
print(family)

You can observe that after several executions, the family is increasing one member at a time.