Understanding implicit context loading

The implicit context load method as described in the recipe Using implicit context load to load contexts in Chapter 6, Managing Context Variables.

Pros

The implicit context load technique is centrally managed, thus ensuring consistent use across a project. Developers do not need to remember to set context variables, because they will be set automatically.

The use of external files is good practice for managing contexts, as they are less likely to be overwritten during deployment.

Cons

This method provides the option to fail if a context variable is not present or does not contain data, which is great for validating your parameters. Unfortunately this option checks against the whole context of a job, including context variables that are only used locally within the job and will fail if the local job variables are not present in the external file. Thus we have a choice; we can add single use variables to our shared context, potentially making it very messy, or we have to turn off the option to fail the job if we find problems with the context variables, thus removing a level of validation that we may prefer to keep.

Conclusion

The implicit context load method provides a consistent method for loading contexts and requires the least effort to set up and maintain, but it does suffer from a lack of fine grain since the context variables are applied to every job in a project.

It is good for projects where there is high degree of commonality in the processing and the resources.