Add support for Trino (dropbox#381)

1. Inherit from presto
2. Add travis test script
3. Add test cases

.travis.yml

@@ -6,15 +6,15 @@ matrix:
     # https://docs.python.org/devguide/#status-of-python-branches
     # One build pulls latest versions dynamically
     - python: 3.6
-      env: CDH=cdh5 CDH_VERSION=5 PRESTO=RELEASE SQLALCHEMY=sqlalchemy>=1.3.0
+      env: CDH=cdh5 CDH_VERSION=5 PRESTO=RELEASE TRINO=RELEASE SQLALCHEMY=sqlalchemy>=1.3.0
     - python: 3.6
-      env: CDH=cdh5 CDH_VERSION=5.10.1 PRESTO=0.147 SQLALCHEMY=sqlalchemy>=1.3.0
+      env: CDH=cdh5 CDH_VERSION=5.10.1 PRESTO=0.147 TRINO=351 SQLALCHEMY=sqlalchemy>=1.3.0
     - python: 3.5
-      env: CDH=cdh5 CDH_VERSION=5.10.1 PRESTO=0.147 SQLALCHEMY=sqlalchemy>=1.3.0
+      env: CDH=cdh5 CDH_VERSION=5.10.1 PRESTO=0.147 TRINO=351 SQLALCHEMY=sqlalchemy>=1.3.0
     - python: 3.4
-      env: CDH=cdh5 CDH_VERSION=5.10.1 PRESTO=0.147 SQLALCHEMY=sqlalchemy>=1.3.0
+      env: CDH=cdh5 CDH_VERSION=5.10.1 PRESTO=0.147 TRINO=351 SQLALCHEMY=sqlalchemy>=1.3.0
     - python: 2.7
-      env: CDH=cdh5 CDH_VERSION=5.10.1 PRESTO=0.147 SQLALCHEMY=sqlalchemy>=1.3.0
+      env: CDH=cdh5 CDH_VERSION=5.10.1 PRESTO=0.147 TRINO=351 SQLALCHEMY=sqlalchemy>=1.3.0
 install:
   - ./scripts/travis-install.sh
   - pip install codecov

README.rst

@@ -17,7 +17,7 @@ DB-API
 ------
 .. code-block:: python
 
-    from pyhive import presto  # or import hive
+    from pyhive import presto  # or import hive or import trino
     cursor = presto.connect('localhost').cursor()
     cursor.execute('SELECT * FROM my_awesome_data LIMIT 10')
     print cursor.fetchone()
@@ -63,6 +63,8 @@ First install this package to register it with SQLAlchemy (see ``setup.py``).
     from sqlalchemy.schema import *
     # Presto
     engine = create_engine('presto://localhost:8080/hive/default')
+    # Trino
+    engine = create_engine('trino://localhost:8080/hive/default')
     # Hive
     engine = create_engine('hive://localhost:10000/default')
     logs = Table('my_awesome_data', MetaData(bind=engine), autoload=True)
@@ -79,12 +81,18 @@ Passing session configuration
     # DB-API
     hive.connect('localhost', configuration={'hive.exec.reducers.max': '123'})
     presto.connect('localhost', session_props={'query_max_run_time': '1234m'})
+    trino.connect('localhost',  session_props={'query_max_run_time': '1234m'})
     # SQLAlchemy
     create_engine(
         'presto://user@host:443/hive',
         connect_args={'protocol': 'https',
                       'session_props': {'query_max_run_time': '1234m'}}
     )
+    create_engine(
+        'trino://user@host:443/hive',
+        connect_args={'protocol': 'https',
+                      'session_props': {'query_max_run_time': '1234m'}}
+    )
     create_engine(
         'hive://user@host:10000/database',
         connect_args={'configuration': {'hive.exec.reducers.max': '123'}},
@@ -102,11 +110,13 @@ Install using
 
 - ``pip install 'pyhive[hive]'`` for the Hive interface and
 - ``pip install 'pyhive[presto]'`` for the Presto interface.
+- ``pip install 'pyhive[trino]'`` for the Trino interface
 
 PyHive works with
 
 - Python 2.7 / Python 3
 - For Presto: Presto install
+- For Trino: Trino install
 - For Hive: `HiveServer2 <https://cwiki.apache.org/confluence/display/Hive/Setting+up+HiveServer2>`_ daemon
 
 Changelog

pyhive/sqlalchemy_trino.py

@@ -0,0 +1,73 @@
+"""Integration between SQLAlchemy and Trino.
+
+Some code based on
+https://github.com/zzzeek/sqlalchemy/blob/rel_0_5/lib/sqlalchemy/databases/sqlite.py
+which is released under the MIT license.
+"""
+
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import re
+from sqlalchemy import exc
+from sqlalchemy import types
+from sqlalchemy import util
+# TODO shouldn't use mysql type
+from sqlalchemy.databases import mysql
+from sqlalchemy.engine import default
+from sqlalchemy.sql import compiler
+from sqlalchemy.sql.compiler import SQLCompiler
+
+from pyhive import trino
+from pyhive.common import UniversalSet
+from pyhive.sqlalchemy_presto import PrestoDialect, PrestoCompiler, PrestoIdentifierPreparer
+
+class TrinoIdentifierPreparer(PrestoIdentifierPreparer):
+    pass
+
+
+_type_map = {
+    'boolean': types.Boolean,
+    'tinyint': mysql.MSTinyInteger,
+    'smallint': types.SmallInteger,
+    'integer': types.Integer,
+    'bigint': types.BigInteger,
+    'real': types.Float,
+    'double': types.Float,
+    'varchar': types.String,
+    'timestamp': types.TIMESTAMP,
+    'date': types.DATE,
+    'varbinary': types.VARBINARY,
+}
+
+
+class TrinoCompiler(PrestoCompiler):
+    pass
+
+
+class TrinoTypeCompiler(PrestoCompiler):
+    def visit_CLOB(self, type_, **kw):
+        raise ValueError("Trino does not support the CLOB column type.")
+
+    def visit_NCLOB(self, type_, **kw):
+        raise ValueError("Trino does not support the NCLOB column type.")
+
+    def visit_DATETIME(self, type_, **kw):
+        raise ValueError("Trino does not support the DATETIME column type.")
+
+    def visit_FLOAT(self, type_, **kw):
+        return 'DOUBLE'
+
+    def visit_TEXT(self, type_, **kw):
+        if type_.length:
+            return 'VARCHAR({:d})'.format(type_.length)
+        else:
+            return 'VARCHAR'
+
+
+class TrinoDialect(PrestoDialect):
+    name = 'trino'
+
+    @classmethod
+    def dbapi(cls):
+        return trino

pyhive/tests/test_trino.py

@@ -0,0 +1,96 @@
+"""Trino integration tests.
+
+These rely on having a Trino+Hadoop cluster set up.
+They also require a tables created by make_test_tables.sh.
+"""
+
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import contextlib
+import os
+import requests
+
+from pyhive import exc
+from pyhive import trino
+from pyhive.tests.dbapi_test_case import DBAPITestCase
+from pyhive.tests.dbapi_test_case import with_cursor
+from pyhive.tests.test_presto import TestPresto
+import mock
+import unittest
+import datetime
+
+_HOST = 'localhost'
+_PORT = '18080'
+
+
+class TestTrino(TestPresto):
+    __test__ = True
+
+    def connect(self):
+        return trino.connect(host=_HOST, port=_PORT, source=self.id())
+
+    def test_bad_protocol(self):
+        self.assertRaisesRegexp(ValueError, 'Protocol must be',
+                                lambda: trino.connect('localhost', protocol='nonsense').cursor())
+
+    def test_escape_args(self):
+        escaper = trino.TrinoParamEscaper()
+
+        self.assertEqual(escaper.escape_args((datetime.date(2020, 4, 17),)),
+                         ("date '2020-04-17'",))
+        self.assertEqual(escaper.escape_args((datetime.datetime(2020, 4, 17, 12, 0, 0, 123456),)),
+                         ("timestamp '2020-04-17 12:00:00.123'",))
+
+    @with_cursor
+    def test_description(self, cursor):
+        cursor.execute('SELECT 1 AS foobar FROM one_row')
+        self.assertEqual(cursor.description, [('foobar', 'integer', None, None, None, None, True)])
+        self.assertIsNotNone(cursor.last_query_id)
+
+    @with_cursor
+    def test_complex(self, cursor):
+        cursor.execute('SELECT * FROM one_row_complex')
+        # TODO Trino drops the union field
+
+        tinyint_type = 'tinyint'
+        smallint_type = 'smallint'
+        float_type = 'real'
+        self.assertEqual(cursor.description, [
+            ('boolean', 'boolean', None, None, None, None, True),
+            ('tinyint', tinyint_type, None, None, None, None, True),
+            ('smallint', smallint_type, None, None, None, None, True),
+            ('int', 'integer', None, None, None, None, True),
+            ('bigint', 'bigint', None, None, None, None, True),
+            ('float', float_type, None, None, None, None, True),
+            ('double', 'double', None, None, None, None, True),
+            ('string', 'varchar', None, None, None, None, True),
+            ('timestamp', 'timestamp', None, None, None, None, True),
+            ('binary', 'varbinary', None, None, None, None, True),
+            ('array', 'array(integer)', None, None, None, None, True),
+            ('map', 'map(integer,integer)', None, None, None, None, True),
+            ('struct', 'row(a integer,b integer)', None, None, None, None, True),
+            # ('union', 'varchar', None, None, None, None, True),
+            ('decimal', 'decimal(10,1)', None, None, None, None, True),
+        ])
+        rows = cursor.fetchall()
+        expected = [(
+            True,
+            127,
+            32767,
+            2147483647,
+            9223372036854775807,
+            0.5,
+            0.25,
+            'a string',
+            '1970-01-01 00:00:00.000',
+            b'123',
+            [1, 2],
+            {"1": 2, "3": 4},  # Trino converts all keys to strings so that they're valid JSON
+            [1, 2],  # struct is returned as a list of elements
+            # '{0:1}',
+            '0.1',
+        )]
+        self.assertEqual(rows, expected)
+        # catch unicode/str
+        self.assertEqual(list(map(type, rows[0])), list(map(type, expected[0])))

pyhive/trino.py

@@ -0,0 +1,144 @@
+"""DB-API implementation backed by Trino
+
+See http://www.python.org/dev/peps/pep-0249/
+
+Many docstrings in this file are based on the PEP, which is in the public domain.
+"""
+
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import logging
+
+import requests
+
+# Make all exceptions visible in this module per DB-API
+from pyhive.common import DBAPITypeObject
+from pyhive.exc import *  # noqa
+from pyhive.presto import Connection as PrestoConnection, Cursor as PrestoCursor, PrestoParamEscaper
+
+try:  # Python 3
+    import urllib.parse as urlparse
+except ImportError:  # Python 2
+    import urlparse
+
+# PEP 249 module globals
+apilevel = '2.0'
+threadsafety = 2  # Threads may share the module and connections.
+paramstyle = 'pyformat'  # Python extended format codes, e.g. ...WHERE name=%(name)s
+
+_logger = logging.getLogger(__name__)
+
+
+class TrinoParamEscaper(PrestoParamEscaper):
+    pass
+
+
+_escaper = TrinoParamEscaper()
+
+
+def connect(*args, **kwargs):
+    """Constructor for creating a connection to the database. See class :py:class:`Connection` for
+    arguments.
+
+    :returns: a :py:class:`Connection` object.
+    """
+    return Connection(*args, **kwargs)
+
+
+class Connection(PrestoConnection):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+    def cursor(self):
+        """Return a new :py:class:`Cursor` object using the connection."""
+        return Cursor(*self._args, **self._kwargs)
+
+
+class Cursor(PrestoCursor):
+    """These objects represent a database cursor, which is used to manage the context of a fetch
+    operation.
+
+    Cursors are not isolated, i.e., any changes done to the database by a cursor are immediately
+    visible by other cursors or connections.
+    """
+
+    def execute(self, operation, parameters=None):
+        """Prepare and execute a database operation (query or command).
+
+        Return values are not defined.
+        """
+        headers = {
+            'X-Trino-Catalog': self._catalog,
+            'X-Trino-Schema': self._schema,
+            'X-Trino-Source': self._source,
+            'X-Trino-User': self._username,
+        }
+
+        if self._session_props:
+            headers['X-Trino-Session'] = ','.join(
+                '{}={}'.format(propname, propval)
+                for propname, propval in self._session_props.items()
+            )
+
+        # Prepare statement
+        if parameters is None:
+            sql = operation
+        else:
+            sql = operation % _escaper.escape_args(parameters)
+
+        self._reset_state()
+
+        self._state = self._STATE_RUNNING
+        url = urlparse.urlunparse((
+            self._protocol,
+            '{}:{}'.format(self._host, self._port), '/v1/statement', None, None, None))
+        _logger.info('%s', sql)
+        _logger.debug("Headers: %s", headers)
+        response = self._requests_session.post(
+            url, data=sql.encode('utf-8'), headers=headers, **self._requests_kwargs)
+        self._process_response(response)
+
+    def _process_response(self, response):
+        """Given the JSON response from Trino's REST API, update the internal state with the next
+        URI and any data from the response
+        """
+        # TODO handle HTTP 503
+        if response.status_code != requests.codes.ok:
+            fmt = "Unexpected status code {}\n{}"
+            raise OperationalError(fmt.format(response.status_code, response.content))
+
+        response_json = response.json()
+        _logger.debug("Got response %s", response_json)
+        assert self._state == self._STATE_RUNNING, "Should be running if processing response"
+        self._nextUri = response_json.get('nextUri')
+        self._columns = response_json.get('columns')
+        if 'id' in response_json:
+            self.last_query_id = response_json['id']
+        if 'X-Trino-Clear-Session' in response.headers:
+            propname = response.headers['X-Trino-Clear-Session']
+            self._session_props.pop(propname, None)
+        if 'X-Trino-Set-Session' in response.headers:
+            propname, propval = response.headers['X-Trino-Set-Session'].split('=', 1)
+            self._session_props[propname] = propval
+        if 'data' in response_json:
+            assert self._columns
+            new_data = response_json['data']
+            self._decode_binary(new_data)
+            self._data += map(tuple, new_data)
+        if 'nextUri' not in response_json:
+            self._state = self._STATE_FINISHED
+        if 'error' in response_json:
+            raise DatabaseError(response_json['error'])
+
+
+#
+# Type Objects and Constructors
+#
+
+
+# See types in trino-main/src/main/java/com/facebook/trino/tuple/TupleInfo.java
+FIXED_INT_64 = DBAPITypeObject(['bigint'])
+VARIABLE_BINARY = DBAPITypeObject(['varchar'])
+DOUBLE = DBAPITypeObject(['double'])
+BOOLEAN = DBAPITypeObject(['boolean'])

scripts/travis-conf/trino/catalog/hive.properties

@@ -0,0 +1,2 @@
+connector.name=hive-hadoop2
+hive.metastore.uri=thrift://localhost:9083

scripts/travis-conf/trino/config.properties

@@ -0,0 +1,7 @@
+coordinator=true
+node-scheduler.include-coordinator=true
+http-server.http.port=18080
+query.max-memory=100MB
+query.max-memory-per-node=100MB
+discovery-server.enabled=true
+discovery.uri=http://localhost:18080