[jboss-as7-dev] cli variables

[Hynek Mlnarik]

Hi,

thanks for the effort, this feature will be very helpful indeed!

Overall I like your approach, yet in case of "echo" command I'd prefer mandatory use of $ character before variable name, i.e. to use:
    [standalone at localhost:9990 /] echo $prod_db
instead of proposed:
    [standalone at localhost:9990 /] echo prod_db

In other words, to apply the same substitution rules to "echo" parameters as to the rest of use cases where variable value is read. This would also be more consistent with shell standards, hence will be easily grabbed by administrators.


Further, do you plan recursive substitution evaluation? E.g. something like this:
[standalone at localhost:9990 /] set prod_db_pgsqlDS=/subsystem=datasources/data-source=ExampleDSPgSQL
[standalone at localhost:9990 /] set prod_db_mysqlDS=/subsystem=datasources/data-source=ExampleDSMySQL
[standalone at localhost:9990 /] set ds=pgsqlDS
[standalone at localhost:9990 /] echo ${prod_db_$ds}
/subsystem=datasources/data-source=ExampleDSPgSQL


--Hynek

On Mon December 2 2013 15:06:52 Alexey Loubyansky wrote:
> There is this issue to provide CLI preferences 
> https://issues.jboss.org/browse/WFLY-1063. Here I'd like to address 
> mainly this part
> 
> "prod-db = /subsystem=jadada/database=jadada/
> so you could call prod-db:read-resource"
> 
> I'd like to get some opinion on the way it's gonna be implemented (and 
> what I've done so far on a local branch).
> 
> So, to address that I introduced variables. A variable starts with a $, 
> e.g. $prod_db. (Using simply prod_db is not a good idea since it might 
> conflict with actual parts of the paths, names, etc)
> 
> Variables can be introduced with
> 
> [disconnected /] set prod_db=/subsystem=datasources/data-source=ExampleDS
> 
> Read with
> 
> [standalone at localhost:9990 /] echo prod_db
> /subsystem=datasources/data-source=ExampleDS
> 
> And unset with
> 
> [standalone at localhost:9990 /] unset prod_db
> 
> 'echo' without parameters will list all the variables and their values, 
> 'set prod_db=' will have the same effect as 'unset prod_db', 
> set/echo/unset will work with and w/o '$' prefix, tab-completion works 
> everywhere.
> 
> The variables may appear in:
> 
> - operation request addresses, e.g. $prod_db/statistics=jdbc:read-resource;
> - operation names, e.g. $prod_db:$op(include-runtime=true);
> - operation parameter names and values, e.g. 
> $prod_db:$op($param=$param_value);
> - the same for commands.
> 
> Tab-completion helps complete the names as long as you type in '$' and 
> then the rest of the line after the variable as usual.
> 
> Variables added during the session are not persisted anywhere. But I've 
> added .jbossclirc file. This file can be located in the current 
> directory, wildfly home bin directory or specified with a system 
> property. The content of the file is usual CLI commands and/or 
> operations. So, the variables could be initialized there. This file, if 
> located, will be executed before the CLI session (interactive or not) 
> starts (but also after the system properties specified with --properties 
> are set).
> 
> As a side effect, '$' is now a special character and will have to be 
> escaped. Otherwise the CLI might complain about an unresolved variable. 
> So, this could potentially cause problems for existing scripts using $.
> 
> Note, most of this replacement stuff can already be done with system 
> properties using ${xxx} format (and btw scripts using '$' as in '${xxx}' 
> won't be affected, of course).
> 
> And for now I've made variable names follow the rules for Java identifiers.
> 
> Any remarks, objections or suggestions?
> 
> Thanks,
> Alexey
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