Outputting a visual graph of the component hierarchy

We have a huge component hierarchy, with many levels of subcomponents as well as “parallel” components (ie a dev component that extends the app component and replaces it, so it has all the same bindings / component hierarchy plus some dev bindings).

Our component hierarchy map to regions of the app (e.g. App scope > LoggedIn scope > Settings scope > Printer Settings scope > Add New Printer scope) so this would give us a nice graph of how the app is structured.

Dagger1 used to output .dot files for bindings, which was fun but not practical (too many bindings). It would be great if Dagger2 could output a .dot file mapping the component hierarchy, or some other format.

[arunkumar9t2]

I was able to use Dagger SPI + GraphViz to build https://github.com/arunkumar9t2/scabbard. It also has an IDE plugin to link @Component to generated graph.

Example:

To solve the too many bindings problem, I group the bindings by component path to keep the graph readable, however this has few side effects which I plan to address. (Fixed in 0.3.0).

I also believe with the current SPI, it is possible to build component hierarchy like @pyricau suggested. I plan to try this some time soon. Any feedback greatly appreciated, thanks.

Since 0.4.0, Scabbard supports component hierarchy as originally mentioned in the issue.

[netdpb]

As Ron said, we are working on something that will let you inspect the binding graph, and even add validation rules at compile time. It’s not nearly ready, and probably won’t hit until next quarter.