[wildfly-dev] Map / reduce for management operations

TL;DR For management clients it is tedious and awkward to read resources / attributes in big domains (e.g. return the state of all running servers across all hosts which are part of server group "foo"). Today this requires to setup multiple composite operations *on the client* which need to be executed in a specific order. This proposal suggests a new operation which collects all relevant information *on the server* and returns only the relevant data in one go to the client. -------------------- # Background: In the admin console we often need to read specific attributes across a domain or across a deeply nested resource: - List all enabled data sources of the current profile - Show the port offset of all running servers across all hosts - Get all users which belong to role Operator Even for small domains with two server groups and a small number of servers this procedure is awkward and error prone. What makes it even more difficult is the asynchronous nature of the admin console. Soon you end up in a deeply nested callback-hell. Besides that these 'queries' lead to poor performance for big domains with tens of groups, hosts and servers. # Proposal / Prototype The GitHub repository at [1] contains a more detailed description of the problem statement and a working prototype. This includes details such as how to address the requested resources, how the information is retrieved and how to handle errors. The proposal also includes a way to filter and reduce the resources against a list of attributes and values *before* the response is sent to the client. [1] https://github.com/hpehl/map-reduce <https://github.com/hpehl/map-reduce> --- Harald Pehl JBoss by Red Hat http://hpehl.info