Elasticsearch DSL
Deprecation notice
As of release 8.18.0, the Elasticsearch DSL package is part of the official
Elasticsearch Python client <https://github.com/elastic/elasticsearch-py>_,
so a separate install is not needed anymore. To migrate, follow these steps:
- Uninstall the
elasticsearch-dsl package
- Make sure you have version 8.18.0 or newer of the
elasticsearch package
installed
- Replace
elasticsearch_dsl with elasticsearch.dsl in your imports
To prevent applications from breaking unexpectedly due to this change, the
8.18.0 release of this package automatically redirects all imports to the
corresponding modules of the Python client package.
The following instructions only apply to versions 8.17 and older of this
package.
Introduction
Elasticsearch DSL is a high-level library whose aim is to help with writing and
running queries against Elasticsearch. It is built on top of the official
low-level client (elasticsearch-py <https://github.com/elastic/elasticsearch-py>_).
It provides a more convenient and idiomatic way to write and manipulate
queries. It stays close to the Elasticsearch JSON DSL, mirroring its
terminology and structure. It exposes the whole range of the DSL from Python
either directly using defined classes or a queryset-like expressions.
It also provides an optional wrapper for working with documents as Python
objects: defining mappings, retrieving and saving documents, wrapping the
document data in user-defined classes.
To use the other Elasticsearch APIs (eg. cluster health) just use the
underlying client.
Installation
::
pip install elasticsearch-dsl
Examples
Please see the examples <https://github.com/elastic/elasticsearch-dsl-py/tree/master/examples>_
directory to see some complex examples using elasticsearch-dsl.
Compatibility
The library is compatible with all Elasticsearch versions since 2.x but you
have to use a matching major version:
For Elasticsearch 8.0 and later, use the major version 8 (8.x.y) of the
library.
For Elasticsearch 7.0 and later, use the major version 7 (7.x.y) of the
library.
For Elasticsearch 6.0 and later, use the major version 6 (6.x.y) of the
library.
For Elasticsearch 5.0 and later, use the major version 5 (5.x.y) of the
library.
For Elasticsearch 2.0 and later, use the major version 2 (2.x.y) of the
library.
The recommended way to set your requirements in your setup.py or
requirements.txt is::
# Elasticsearch 8.x
elasticsearch-dsl>=8.0.0,<9.0.0
# Elasticsearch 7.x
elasticsearch-dsl>=7.0.0,<8.0.0
# Elasticsearch 6.x
elasticsearch-dsl>=6.0.0,<7.0.0
# Elasticsearch 5.x
elasticsearch-dsl>=5.0.0,<6.0.0
# Elasticsearch 2.x
elasticsearch-dsl>=2.0.0,<3.0.0
The development is happening on main, older branches only get bugfix releases
Search Example
Let's have a typical search request written directly as a dict:
.. code:: python
from elasticsearch import Elasticsearch
client = Elasticsearch("https://localhost:9200")
response = client.search(
index="my-index",
body={
"query": {
"bool": {
"must": [{"match": {"title": "python"}}],
"must_not": [{"match": {"description": "beta"}}],
"filter": [{"term": {"category": "search"}}]
}
},
"aggs" : {
"per_tag": {
"terms": {"field": "tags"},
"aggs": {
"max_lines": {"max": {"field": "lines"}}
}
}
}
}
)
for hit in response['hits']['hits']:
print(hit['_score'], hit['_source']['title'])
for tag in response['aggregations']['per_tag']['buckets']:
print(tag['key'], tag['max_lines']['value'])
The problem with this approach is that it is very verbose, prone to syntax
mistakes like incorrect nesting, hard to modify (eg. adding another filter) and
definitely not fun to write.
Let's rewrite the example using the Python DSL:
.. code:: python
from elasticsearch import Elasticsearch
from elasticsearch_dsl import Search
client = Elasticsearch("https://localhost:9200")
s = Search(using=client, index="my-index") \
.filter("term", category="search") \
.query("match", title="python") \
.exclude("match", description="beta")
s.aggs.bucket('per_tag', 'terms', field='tags') \
.metric('max_lines', 'max', field='lines')
response = s.execute()
for hit in response:
print(hit.meta.score, hit.title)
for tag in response.aggregations.per_tag.buckets:
print(tag.key, tag.max_lines.value)
As you see, the library took care of:
- creating appropriate
Query objects by name (eq. "match")
- composing queries into a compound
bool query
- putting the
term query in a filter context of the bool query
- providing a convenient access to response data
- no curly or square brackets everywhere
Persistence Example
Let's have a simple Python class representing an article in a blogging system:
.. code:: python
from datetime import datetime
from elasticsearch_dsl import Document, Date, Integer, Keyword, Text, connections
# Define a default Elasticsearch client
connections.create_connection(hosts="https://localhost:9200")
class Article(Document):
title = Text(analyzer='snowball', fields={'raw': Keyword()})
body = Text(analyzer='snowball')
tags = Keyword()
published_from = Date()
lines = Integer()
class Index:
name = 'blog'
settings = {
"number_of_shards": 2,
}
def save(self, ** kwargs):
self.lines = len(self.body.split())
return super(Article, self).save(** kwargs)
def is_published(self):
return datetime.now() > self.published_from
# create the mappings in elasticsearch
Article.init()
# create and save and article
article = Article(meta={'id': 42}, title='Hello world!', tags=['test'])
article.body = ''' looong text '''
article.published_from = datetime.now()
article.save()
article = Article.get(id=42)
print(article.is_published())
# Display cluster health
print(connections.get_connection().cluster.health())
In this example you can see:
- providing a default connection
- defining fields with mapping configuration
- setting index name
- defining custom methods
- overriding the built-in
.save() method to hook into the persistence
life cycle
- retrieving and saving the object into Elasticsearch
- accessing the underlying client for other APIs
You can see more in the persistence chapter of the documentation.
Migration from elasticsearch-py
You don't have to port your entire application to get the benefits of the
Python DSL, you can start gradually by creating a Search object from your
existing dict, modifying it using the API and serializing it back to a
dict:
.. code:: python
body = {...} # insert complicated query here
# Convert to Search object
s = Search.from_dict(body)
# Add some filters, aggregations, queries, ...
s.filter("term", tags="python")
# Convert back to dict to plug back into existing code
body = s.to_dict()
Development
Activate Virtual Environment (virtualenvs <http://docs.python-guide.org/en/latest/dev/virtualenvs/>_):
.. code:: bash
$ virtualenv venv
$ source venv/bin/activate
To install all of the dependencies necessary for development, run:
.. code:: bash
$ pip install -e '.[develop]'
To run all of the tests for elasticsearch-dsl-py, run:
.. code:: bash
$ python setup.py test
Alternatively, it is possible to use the run_tests.py script in
test_elasticsearch_dsl, which wraps pytest <http://doc.pytest.org/en/latest/>_, to run subsets of the test suite. Some
examples can be seen below:
.. code:: bash
# Run all of the tests in `test_elasticsearch_dsl/test_analysis.py`
$ ./run_tests.py test_analysis.py
# Run only the `test_analyzer_serializes_as_name` test.
$ ./run_tests.py test_analysis.py::test_analyzer_serializes_as_name
pytest will skip tests from test_elasticsearch_dsl/test_integration
unless there is an instance of Elasticsearch on which a connection can occur.
By default, the test connection is attempted at localhost:9200, based on
the defaults specified in the elasticsearch-py Connection <https://github.com/elastic/elasticsearch-py/blob/master/elasticsearch /connection/base.py#L29>_ class. Because running the integration
tests will cause destructive changes to the Elasticsearch cluster, only run
them when the associated cluster is empty. As such, if the
Elasticsearch instance at localhost:9200 does not meet these requirements,
it is possible to specify a different test Elasticsearch server through the
TEST_ES_SERVER environment variable.
.. code:: bash
$ TEST_ES_SERVER=my-test-server:9201 ./run_tests
Documentation
Documentation is available at https://elasticsearch-dsl.readthedocs.io.
Contribution Guide
Want to hack on Elasticsearch DSL? Awesome! We have Contribution-Guide <https://github.com/elastic/elasticsearch-dsl-py/blob/master/CONTRIBUTING.rst>_.
License
Copyright 2013 Elasticsearch
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
