superset/migrations/versions/7fcdcde0761c_.py

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"""Reduce position_json size by remove extra space and component id prefix

Revision ID: 7fcdcde0761c
Revises: c18bd4186f15
Create Date: 2018-08-01 11:47:02.233971

"""

# revision identifiers, used by Alembic.
import json
import re

import sqlalchemy as sa
from alembic import op
from sqlalchemy.ext.declarative import declarative_base

from superset import db

revision = "7fcdcde0761c"
down_revision = "c18bd4186f15"

Base = declarative_base()


class Dashboard(Base):
    """Declarative class to do query in upgrade"""

    __tablename__ = "dashboards"
    id = sa.Column(sa.Integer, primary_key=True)
    dashboard_title = sa.Column(sa.String(500))
    position_json = sa.Column(sa.Text)


def is_v2_dash(positions):
    return (
        isinstance(positions, dict) and positions.get("DASHBOARD_VERSION_KEY") == "v2"
    )


def upgrade():
    bind = op.get_bind()
    session = db.Session(bind=bind)

    dashboards = session.query(Dashboard).all()
    for i, dashboard in enumerate(dashboards):
        original_text = dashboard.position_json or ""
        position_json = json.loads(original_text or "{}")
        if is_v2_dash(position_json):
            # re-dump the json data and remove leading and trailing white spaces
            text = json.dumps(
                position_json, indent=None, separators=(",", ":"), sort_keys=True
            )
            # remove DASHBOARD_ and _TYPE prefix/suffix in all the component ids
            text = re.sub(r"DASHBOARD_(?!VERSION)", "", text)
            text = text.replace("_TYPE", "")

            dashboard.position_json = text
            print(
                "dash id:{} position_json size from {} to {}".format(
                    dashboard.id, len(original_text), len(text)
                )
            )
            session.merge(dashboard)
            session.commit()


def downgrade():
    pass