[teiid-users] Alternative scripting envrionment for AdminShell

[Steven Hawkins]

Hello all,

Before we get to a 7.0 RC, I would like to propose replacing our BeanShell based Adminshell with one based upon Groovy.  The rationale for this change is:
1. BeanShell is no longer maintained
2. BeanShell interactive and graphical tools have usability issues (for example script development with AdminShell typically involves opening a separate text editor)
3. We have deep hooks into the scripting language for the admin shell that are difficult to maintain.

While we could stay with BeanShell and address 2/3 it does not seem worth the effort given that we have the opportunity of a major release to make major changes.  If we fully reduce our hooks into the scripting language/shell (which would move all relevant logic into Java), then the things we could loose are:

A. A help system based upon the script source
B. A contextual (where the connection context is shown on the prompt) command system
C. Grammar extension for SQL, such that just entering a SQL is all that is required for execution.

The things we would immediately gain with Groovy are:

A command line shell that has a command history, maintains an editable buffer, and supports built-in script recording.
A graphical console that functions as a simple text editor based IDE (with syntax highlighting) and supports full script and selected text execution.  
Built-in support for simplifying JDBC execution (which is extensible to support getting our debug logs, query plans, etc.), see http://groovy.codehaus.org/Tutorial+6+-+Groovy+SQL.
And a wealth of other built-in Groovy modules for common activities, such as XML handling.

To address A we would want to expose our relevant JavaDocs via help extensions in both the command line and graphical tools.
I would argue that it's a matter of developer preference as to whether we address B.  See the below example scipts.

Example Groovy script:

import static org.teiid.adminshell.AdminShell.*  //optional - we could just as easily add this into the shell context automatically

admin = connectAsAdmin()

admin.exportConnectionFactory("TPCR_S2k", "test.xml")

sql = connect()

sql.eachRow("select * from tables", { println it })



Current AdminShell script:

connectAsAdmin();

exportConnectionFactory("TPCR_S2k", "test.xml");

connect();

select * from tables;

printResultSet();


With the Groovy script (note ending ; are optional) explicit admin and sql objects are used to represent their respective connections.  If additional connections are needed, then additional variables are introduced.  In AdminShell the current connection is contextually bound so that functions may be called without explicitly identifying which connection is used.  The same logic could be introduced in the Groovy hooks by providing static hooks to all the methods available on the Admin and Sql objects.

I would propose that we would need to drop support for C completely, since it requires both the notion of a contextual connection and extending the host grammar (which cannot be done without deep hooks).

Any thoughts?

Steve