Make pandas an optional core dependency (#17575)

We only use `pandas` in `DbApiHook.get_pandas_df`. Not all users use it, plus
while `pandas` now supports many pre-compiled packages it still can take forever where
it needs to be compiled.

So for first-time users this can be a turn off. If pandas is already installed this
will work fine, but if not users have an option to run `pip install apache-airflow[pandas]`

closes #12500

Author: kaxil

BREEZE.rst

@@ -1315,8 +1315,8 @@ This is the current syntax for  `./breeze <./breeze>`_:
 
           Production image:
                  async,amazon,celery,cncf.kubernetes,docker,dask,elasticsearch,ftp,grpc,hashicorp,
-                 http,ldap,google,google_auth,microsoft.azure,mysql,postgres,redis,sendgrid,sftp,
-                 slack,ssh,statsd,virtualenv
+                 http,ldap,google,google_auth,microsoft.azure,mysql,pandas,postgres,redis,sendgrid,
+                 sftp,slack,ssh,statsd,virtualenv
 
   --image-tag TAG
           Additional tag in the image.
@@ -1914,8 +1914,8 @@ This is the current syntax for  `./breeze <./breeze>`_:
 
           Production image:
                  async,amazon,celery,cncf.kubernetes,docker,dask,elasticsearch,ftp,grpc,hashicorp,
-                 http,ldap,google,google_auth,microsoft.azure,mysql,postgres,redis,sendgrid,sftp,
-                 slack,ssh,statsd,virtualenv
+                 http,ldap,google,google_auth,microsoft.azure,mysql,pandas,postgres,redis,sendgrid,
+                 sftp,slack,ssh,statsd,virtualenv
 
   --image-tag TAG
           Additional tag in the image.
@@ -2501,8 +2501,8 @@ This is the current syntax for  `./breeze <./breeze>`_:
 
           Production image:
                  async,amazon,celery,cncf.kubernetes,docker,dask,elasticsearch,ftp,grpc,hashicorp,
-                 http,ldap,google,google_auth,microsoft.azure,mysql,postgres,redis,sendgrid,sftp,
-                 slack,ssh,statsd,virtualenv
+                 http,ldap,google,google_auth,microsoft.azure,mysql,pandas,postgres,redis,sendgrid,
+                 sftp,slack,ssh,statsd,virtualenv
 
   --image-tag TAG
           Additional tag in the image.

CONTRIBUTING.rst

@@ -593,8 +593,8 @@ devel_all, devel_ci, devel_hadoop, dingding, discord, doc, docker, druid, elasti
 facebook, ftp, gcp, gcp_api, github_enterprise, google, google_auth, grpc, hashicorp, hdfs, hive,
 http, imap, jdbc, jenkins, jira, kerberos, kubernetes, ldap, leveldb, microsoft.azure,
 microsoft.mssql, microsoft.psrp, microsoft.winrm, mongo, mssql, mysql, neo4j, odbc, openfaas,
-opsgenie, oracle, pagerduty, papermill, password, pinot, plexus, postgres, presto, qds, qubole,
-rabbitmq, redis, s3, salesforce, samba, segment, sendgrid, sentry, sftp, singularity, slack,
+opsgenie, oracle, pagerduty, pandas, papermill, password, pinot, plexus, postgres, presto, qds,
+qubole, rabbitmq, redis, s3, salesforce, samba, segment, sendgrid, sentry, sftp, singularity, slack,
 snowflake, spark, sqlite, ssh, statsd, tableau, telegram, trino, vertica, virtualenv, webhdfs,
 winrm, yandex, zendesk
 

Dockerfile

@@ -34,7 +34,7 @@
 #                        much smaller.
 #
 ARG AIRFLOW_VERSION="2.2.0.dev0"
-ARG AIRFLOW_EXTRAS="async,amazon,celery,cncf.kubernetes,docker,dask,elasticsearch,ftp,grpc,hashicorp,http,ldap,google,google_auth,microsoft.azure,mysql,postgres,redis,sendgrid,sftp,slack,ssh,statsd,virtualenv"
+ARG AIRFLOW_EXTRAS="async,amazon,celery,cncf.kubernetes,docker,dask,elasticsearch,ftp,grpc,hashicorp,http,ldap,google,google_auth,microsoft.azure,mysql,pandas,postgres,redis,sendgrid,sftp,slack,ssh,statsd,virtualenv"
 ARG ADDITIONAL_AIRFLOW_EXTRAS=""
 ARG ADDITIONAL_PYTHON_DEPS=""
 

INSTALL

@@ -97,8 +97,8 @@ devel_all, devel_ci, devel_hadoop, dingding, discord, doc, docker, druid, elasti
 facebook, ftp, gcp, gcp_api, github_enterprise, google, google_auth, grpc, hashicorp, hdfs, hive,
 http, imap, jdbc, jenkins, jira, kerberos, kubernetes, ldap, leveldb, microsoft.azure,
 microsoft.mssql, microsoft.psrp, microsoft.winrm, mongo, mssql, mysql, neo4j, odbc, openfaas,
-opsgenie, oracle, pagerduty, papermill, password, pinot, plexus, postgres, presto, qds, qubole,
-rabbitmq, redis, s3, salesforce, samba, segment, sendgrid, sentry, sftp, singularity, slack,
+opsgenie, oracle, pagerduty, pandas, papermill, password, pinot, plexus, postgres, presto, qds,
+qubole, rabbitmq, redis, s3, salesforce, samba, segment, sendgrid, sentry, sftp, singularity, slack,
 snowflake, spark, sqlite, ssh, statsd, tableau, telegram, trino, vertica, virtualenv, webhdfs,
 winrm, yandex, zendesk
 

UPDATING.md

@@ -73,6 +73,19 @@ https://developers.google.com/style/inclusive-documentation
 
 -->
 
+### `pandas` is now an optional dependency
+
+Previously `pandas` was a core requirement so when you run `pip install apache-airflow` it looked for `pandas`
+library and installed it if it does not exist.
+
+If you want to install `pandas` compatible with Airflow, you can use `[pandas]` extra while
+installing Airflow, example for Python 3.8 and Airflow 2.1.2:
+
+```shell
+pip install -U "apache-airflow[pandas]==2.1.2" \
+  --constraint https://raw.githubusercontent.com/apache/airflow/constraints-2.1.2/constraints-3.8.txt"
+```
+
 ### Dummy trigger rule has been deprecated
 
 `TriggerRule.DUMMY` is replaced by `TriggerRule.ALWAYS`.

airflow/executors/celery_executor.py

@@ -183,14 +183,18 @@ def on_celery_import_modules(*args, **kwargs):
     doesn't matter, but for short tasks this starts to be a noticeable impact.
     """
     import jinja2.ext  # noqa: F401
-    import numpy  # noqa: F401
 
     import airflow.jobs.local_task_job
     import airflow.macros
     import airflow.operators.bash
     import airflow.operators.python
     import airflow.operators.subdag  # noqa: F401
 
+    try:
+        import numpy  # noqa: F401
+    except ImportError:
+        pass
+
     try:
         import kubernetes.client  # noqa: F401
     except ImportError:

airflow/hooks/dbapi.py

@@ -129,7 +129,10 @@ def get_pandas_df(self, sql, parameters=None, **kwargs):
         :param kwargs: (optional) passed into pandas.io.sql.read_sql method
         :type kwargs: dict
         """
-        from pandas.io import sql as psql
+        try:
+            from pandas.io import sql as psql
+        except ImportError:
+            raise Exception("pandas library not installed, run: pip install 'apache-airflow[pandas]'.")
 
         with closing(self.get_conn()) as conn:
             return psql.read_sql(sql, con=conn, params=parameters, **kwargs)

airflow/utils/json.py

@@ -19,9 +19,13 @@
 from datetime import date, datetime
 from decimal import Decimal
 
-import numpy as np
 from flask.json import JSONEncoder
 
+try:
+    import numpy as np
+except ImportError:
+    np = None
+
 try:
     from kubernetes.client import models as k8s
 except ImportError:
@@ -51,7 +55,7 @@ def _default(obj):
             # Technically lossy due to floating point errors, but the best we
             # can do without implementing a custom encode function.
             return float(obj)
-        elif isinstance(
+        elif np is not None and isinstance(
             obj,
             (
                 np.int_,
@@ -68,9 +72,9 @@ def _default(obj):
             ),
         ):
             return int(obj)
-        elif isinstance(obj, np.bool_):
+        elif np is not None and isinstance(obj, np.bool_):
             return bool(obj)
-        elif isinstance(
+        elif np is not None and isinstance(
             obj, (np.float_, np.float16, np.float32, np.float64, np.complex_, np.complex64, np.complex128)
         ):
             return float(obj)

docs/apache-airflow/extra-packages-ref.rst

@@ -62,6 +62,8 @@ python dependencies for the provided package.
 +---------------------+-----------------------------------------------------+----------------------------------------------------------------------------+
 | leveldb             | ``pip install 'apache-airflow[leveldb]'``           | Required for use leveldb extra in google provider                          |
 +---------------------+-----------------------------------------------------+----------------------------------------------------------------------------+
+| pandas              | ``pip install 'apache-airflow[pandas]'``            | Install Pandas library compatible with Airflow                             |
++---------------------+-----------------------------------------------------+----------------------------------------------------------------------------+
 | password            | ``pip install 'apache-airflow[password]'``          | Password authentication for users                                          |
 +---------------------+-----------------------------------------------------+----------------------------------------------------------------------------+
 | rabbitmq            | ``pip install 'apache-airflow[rabbitmq]'``          | RabbitMQ support as a Celery backend                                       |

setup.cfg

@@ -126,9 +126,6 @@ install_requires =
     numpy;python_version>="3.7"
     # Required by vendored-in connexion
     openapi-spec-validator>=0.2.4
-    # Pandas stopped releasing 3.6 binaries for 1.2.* series.
-    pandas>=0.17.1, <1.2;python_version<"3.7"
-    pandas>=0.17.1, <2.0;python_version>="3.7"
     pendulum~=2.0
     pep562~=1.0;python_version<"3.7"
     psutil>=4.2.0, <6.0.0