[AIRFLOW-4062] Improve docs on install extra package commands (#4966)

Some command for installing extra packages like
`pip install apache-airflow[devel]` cause error
in special situation/shell, We should clear them
by add quotation like
`pip install 'apache-airflow[devel]'`

CONTRIBUTING.md

@@ -85,7 +85,9 @@ The latest API documentation is usually available
 you need to have set up an Airflow development environemnt (see below). Also
 install the `doc` extra.
 
-    pip install -e .[doc]
+```
+pip install -e '.[doc]'
+```
 
 Generate the documentation by running:
 
@@ -112,7 +114,7 @@ There are three ways to setup an Apache Airflow development environment.
   cd $AIRFLOW_HOME
   virtualenv env
   source env/bin/activate
-  pip install -e .[devel]
+  pip install -e '.[devel]'
   ```
 
 2. Using a Docker container
@@ -126,7 +128,7 @@ There are three ways to setup an Apache Airflow development environment.
 
   # Install Airflow with all the required dependencies,
   # including the devel which will provide the development tools
-  pip install -e ".[hdfs,hive,druid,devel]"
+  pip install -e '.[hdfs,hive,druid,devel]'
 
   # Init the database
   airflow initdb

airflow/contrib/example_dags/example_kubernetes_operator.py

@@ -25,7 +25,7 @@
 
 try:
     # Kubernetes is optional, so not available in vanilla Airflow
-    # pip install apache-airflow[kubernetes]
+    # pip install 'apache-airflow[kubernetes]'
     from airflow.contrib.operators.kubernetes_pod_operator import KubernetesPodOperator
 
     args = {
@@ -64,4 +64,4 @@
 except ImportError as e:
     log.warn("Could not import KubernetesPodOperator: " + str(e))
     log.warn("Install kubernetes dependencies with: "
-             "    pip install apache-airflow[kubernetes]")
+             "    pip install 'apache-airflow[kubernetes]'")

airflow/contrib/utils/sendgrid.py

@@ -42,7 +42,7 @@ def send_email(to, subject, html_content, files=None,
 
     To use this plugin:
     0. include sendgrid subpackage as part of your Airflow installation, e.g.,
-    pip install apache-airflow[sendgrid]
+    pip install 'apache-airflow[sendgrid]'
     1. update [email] backend in airflow.cfg, i.e.,
     [email]
     email_backend = airflow.contrib.utils.sendgrid.send_email

docs/howto/secure-connections.rst

@@ -27,8 +27,8 @@ If ``crypto`` package was not installed initially, it means that your Fernet key
 
 You can still enable encryption for passwords within connections by following below steps:
 
-1. Install crypto package ``pip install apache-airflow[crypto]``
-2. Generate fernet_key, using this code snippet below. ``fernet_key`` must be a base64-encoded 32-byte key.
+#. Install crypto package ``pip install 'apache-airflow[crypto]'``
+#. Generate fernet_key, using this code snippet below. ``fernet_key`` must be a base64-encoded 32-byte key:
 
 .. code:: python
 

docs/howto/write-logs.rst

@@ -121,7 +121,7 @@ example:
     remote_base_log_folder = gs://my-bucket/path/to/logs
     remote_log_conn_id = MyGCSConn
 
-#. Install the ``gcp_api`` package first, like so: ``pip install apache-airflow[gcp_api]``.
+#. Install the ``gcp_api`` package first, like so: ``pip install 'apache-airflow[gcp_api]'``.
 #. Make sure a Google Cloud Platform connection hook has been defined in Airflow. The hook should have read and write access to the Google Cloud Storage bucket defined above in ``remote_base_log_folder``.
 #. Restart the Airflow webserver and scheduler, and trigger (or wait for) a new task execution.
 #. Verify that logs are showing up for newly executed tasks in the bucket you've defined.

docs/security.rst

@@ -262,7 +262,7 @@ To use kerberos authentication, you must install Airflow with the `kerberos` ext
 
 .. code-block:: bash
 
-   pip install airflow[kerberos]
+   pip install 'apache-airflow[kerberos]'
 
 OAuth Authentication
 --------------------
@@ -295,7 +295,7 @@ To use GHE authentication, you must install Airflow with the `github_enterprise`
 
 .. code-block:: bash
 
-   pip install airflow[github_enterprise]
+   pip install 'apache-airflow[github_enterprise]'
 
 Setting up GHE Authentication
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -343,7 +343,7 @@ To use Google authentication, you must install Airflow with the `google_auth` ex
 
 .. code-block:: bash
 
-   pip install airflow[google_auth]
+   pip install 'apache-airflow[google_auth]'
 
 Setting up Google Authentication
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^