[DELTASPIKE-378] ProjectStage-aware and Property-aware configuration

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.4
• Fix Version/s: 0.5
• Component/s: Configuration
• Assignee: Mark Struberg
• Reporter: Mark Struberg
• Created: 02/Jun/13 11:08
• Updated: 20/Mar/14 07:44
• Resolved: 11/Sep/13 10:58

Description

In many situations one likes to use different configurations depending on the ProjectStage.

E.g. to take the JPA configuration for the local database from a properties file which contains the credentials and JDBC driver class for the local test setup in ProjectStage Development and UnitTest, but use a JNDI provided DataSource for ProjectStage Production.

Same goes with using various kind of configuration depending on a configured property like e.g. 'dbvendor'. Using some Oracle specific flags if dbvendor is set to 'oracle' vs other flags for 'mysql'.

To not come into chicken/egg issues, I propose that the whole change only affects our ConfigResolver and the producers for @ConfigProperty

I suggest to add 2 new methods to ConfigResolver:

#getProjectStageAwarePropertyValue(String key)

This would basically first do a lookup of key + projectStage, e.g. someKey.Production and if it doesn't find anything, then looks up the configured value without the ProjectStage.

#getPropertyAwarePropertyValue(String key, String propertyName);

The lookup pack for key= 'someconfig', ProjectStage = Production and propertyName = 'dbvendor' would be:

• lookup dbvendor.Production, then if not found do a fallback to dbvendor. Let's say we found the value 'mysql' that way.
• lookup someconfig.mysql.Production
• fallback: lookup someconfig.mysql
• fallback: lookup someconfig.Production
• fallback: lookup someconfig