.. index:: services

.. _sec_OverviewOfServices:

********************
Overview of services
********************

Data Lab *services* run on the server side, close to the data, to minimize large data transfers over the internet.  *Clients* can access these services from anywhere.  The services provide functionality, such as user authentication, database queries, image cutouts, and storage of results, while clients provide a user interface to the services.  The table below organizes the services by function, and lists the typical clients used to access them.

+------------------------+--------------------------------------------------+--------------------------------+
| Function               | Service                                          | Client                         |
+========================+==================================================+================================+
|Sky exploration         | Image discovery tool                             | Web browser                    |
+                        +                                                  +                                +
|                        | Catalog overlay tool                             | Web browser                    |
+                        +                                                  +                                +
|                        | Catalog visualization tool (prototype)           | Web browser                    |
+------------------------+--------------------------------------------------+--------------------------------+
| Authentication         | Web service                                      | Web browser                    |
+                        +                                                  +                                +
|                        | authManager.py                                   | authClient.py, Helpers.py      |
+                        +                                                  +                                +
|                        |                                                  | datalab command                |
+------------------------+--------------------------------------------------+--------------------------------+
| Catalog query          | TAP Service                                      | Web client                     |
+                        +                                                  +                                +
|                        |                                                  | TOPCAT                         |
+                        +                                                  +                                +
|                        |                                                  | queryClient.py, Helpers.py     |
+                        +                                                  +                                +
|                        |                                                  | datalab command                |
+                        +                                                  +                                +
|                        | queryManager.py                                  | queryClient.py, Helpers.py     |
+                        +                                                  +                                +
|                        |                                                  | datalab command                |
+------------------------+--------------------------------------------------+--------------------------------+
| Image query            | Simple Image Access service                      | HTTP                           |
+------------------------+--------------------------------------------------+--------------------------------+
| Query result storage   | myDB                                             | Web client                     |
+                        +                                                  +                                +
|                        |                                                  | queryClient.py, Helpers.py     |
+                        +                                                  +                                +
|                        |                                                  | datalab command                |
+                        +                                                  +                                +
|                        | Virtual storage space,                           | Web client                     |
+                        +  storeManager.py                                 +                                +
|                        |                                                  | queryClient.py, Helpers.py     |
+                        +                                                  +                                +
|                        |                                                  | datalab command                |
+------------------------+--------------------------------------------------+--------------------------------+
| File transfer          | Virtual storage space                            | datalab command                |
+                        +                                                  +                                +
|                        |                                                  | storeClient.py                 |
+------------------------+--------------------------------------------------+--------------------------------+
| Analysis               | Jupyter notebook server                          | Web browser                    |
+------------------------+--------------------------------------------------+--------------------------------+

The graphic below illustrates how a remote user can access Data Lab services.

.. figure:: datalab_cartoon.jpg
   :scale: 100 %
   :alt: Using Data Lab