[jira] [Issue Comment Deleted] (DRILL-5132) Context based dynamic parameterization of views

["Nagarajan Chinnasamy (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/DRILL-5132?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Nagarajan Chinnasamy updated DRILL-5132:
----------------------------------------
    Comment: was deleted

(was: Lets say we have a *pre-defined documented place* where a *session based temporary table* named *context* is created with the following columns:

{code}
session_id, context_type, context_key, context_value
{code}

and say this context table is transparently populated with context based values *as and when a user connection (session) is established*

then a view created with the following kind of query:

{code}
create or replace view dynamic_filter_view as select
   a.field as a_field
   b.field as b_field
from
   a_table as a
left join
   b_table as b
on
   a.bId = b.Id
inner join
   context c
on
   c.session_id=session_id() and
   c.context_type='custom' and
   c.context_key='tenandId" and
   c.context_value=a.tenantId
{code}

This becomes a query that has built-in support for dynamic parameterization that only exposes records of the current tenantId of the current context.

The purpose of context_type column is to inject system defined context values and custom context values.

Custom context values can be obtained through a *custom-context-provider* (like custom-authenticator)

System defined context_types can be *drill.system*, *drill.query* etc.

Does that sound elegant and sensible??!!!! :))

> Context based dynamic parameterization of views
> -----------------------------------------------
>
>                 Key: DRILL-5132
>                 URL: https://issues.apache.org/jira/browse/DRILL-5132
>             Project: Apache Drill
>          Issue Type: Wish
>          Components:  Server
>            Reporter: Nagarajan Chinnasamy
>            Priority: Critical
>              Labels: authentication, context, isolation, jdbcstorage, multi-tenancy
>
> Its known that Views in SQL cannot have custom dynamic parameters/variables.  Please refer to [Justin Swanhart|http://stackoverflow.com/users/679236/justin-swanhart]'s response to [this SO question|http://stackoverflow.com/questions/2281890/can-i-create-view-with-parameter-in-mysql] in handling dynamic parameterization of views. 
> [The PR #685|https://github.com/apache/drill/pull/685] [DRILL-5043|https://issues.apache.org/jira/browse/DRILL-5043?filter=-2] originated based on this requirement so that we could build views that can dynamically filter records based on some dynamic values (like current tenant-id, user role etc.) 
> *Since Drill's basic unit is a View... having such built-in support can bring in dynamism into the whole game.*
> This feature can be utilized for:
> * *Data Isolation in Shared Multi-Tenant environments* based on Custom Tenant Discriminator Column
> * *Data Protection in building Chained Views* with Custom Dynamic Filters
> To explain this further, If we assume that:
> # As and when the user connection is established, we populate session context with session  parameters such as:
> #* Tenant ID of the currently logged in user
> #* Roles of the currently logged in user
> # We expose the session context information through context-based-functions such as:
> #* *session_id* -- that returns unique id of the session
> #* *session_parameter('<parameter-name>')* - that returns the value of the session parameter
> then a view created with the following kind of query:
> {code}
> create or replace view dynamic_filter_view as select
>    a.field as a_field
>    b.field as b_field
> from
>    a_table as a
> left join
>    b_table as b
> on
>    a.bId = b.Id
> where
>    session_parameter('tenantId')=a.tenantId
> {code}
> becomes a query that has built-in support for dynamic parameterization that only returns records of the tenant of the currently logged in user. This is a very useful feature in a shared-multi-tenant environment where data is isolated using multi-tenant-descriminator column 'tenantId'.
> When building chained views this feature will be useful in filtering records based on context based parameters.
> This feature will particularly be useful for data isolation / data protection with *jdbc storage plugins* where drill-authenticated-credentials are not passed to jdbc connection authentication. A jdbc storage  has hard-coded, shared credentials. Hence the the responsibility of data isolation / data protection lies with Views themselves. Hence, the need for built-in support of context based dynamic parameters in Views.



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