REST API to SQLite Blocks log

blocks_log_api.py

import argparse
import sqlite3
from uuid import UUID

from flask import g, json, Flask

from blocks.config import config
from blocks.log.sqlite import ANCESTORS_QUERY

app = Flask(__name__)


@app.route('/experiments', methods=['GET'])
def experiments():
    """List the experiments"""
    experiments = get_db().execute(
        # NOT IN returns NULL if *any* value in the subquery is NULL
        """SELECT DISTINCT uuid FROM status WHERE uuid NOT IN (
            SELECT value FROM status WHERE (
                key = 'resumed_from' AND value IS NOT NULL
            )
        )""").fetchall()
    return json.jsonify({
        'experiments': [UUID(bytes=bytes(e[0])) for e in experiments]
    })


@app.route('/experiments/<uuid>', methods=['get'])
def experiment_uuid(uuid):
    """Get the status of an experiment, and a list of all channels."""
    b_uuid = sqlite3.Binary(UUID(uuid).bytes)
    status = get_db().execute("SELECT key, value FROM status WHERE uuid = ?",
                              (b_uuid,)).fetchall()
    entries = get_db().execute(
        ANCESTORS_QUERY +
        "SELECT DISTINCT key FROM entries WHERE uuid IN ancestors", (b_uuid,)
    ).fetchall()
    return json.jsonify({
        'status': {row[0]: row[1] for row in status
                   if not isinstance(row[1], (sqlite3.Binary, bytes))},
        'entries': [row[0] for row in entries]
    })


@app.route('/experiments/<uuid>/<key>', methods=['get'])
def experiment_uuid_key(uuid, key):
    """Get the values of a channel."""
    b_uuid = sqlite3.Binary(UUID(uuid).bytes)
    # TODO Confirm whether this sort works across platforms
    entries = get_db().execute(
        ANCESTORS_QUERY + "SELECT time, MIN(value) FROM entries "
        "JOIN ancestors ON entries.uuid = ancestors.parent "
        "WHERE uuid IN ancestors AND key = ? GROUP BY time",
        (b_uuid, key)
    ).fetchall()
    iterations_done, values = zip(*entries)
    return json.jsonify({
        'iterations_done': iterations_done,
        key: values
    })


def get_db():
    db = getattr(g, '_database', None)
    if db is None:
        db = sqlite3.connect(args.log)
    return db


@app.teardown_appcontext
def close_connection(exception):
    db = getattr(g, '_database', None)
    if db is not None:
        db.close()

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='Interface for Blocks log.')
    parser.add_argument('log', nargs='?', type=str, help='The log to load.',
                        default=config.sqlite_database)
    args = parser.parse_args()
    app.run(debug=True)