[teiid-dev] Alternative scripting envrionment for AdminShell
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 BeanShell is no longer maintained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