How to update plugin to Goa 3.22?

[jachym-tousek-keboola]

We have a plugin which was using codegen.HTTPServices: https://github.com/keboola/keboola-as-code/blob/7e9dd5a81872aaffb7df871247a6dfcd97cfa8b3/internal/pkg/service/common/goaextension/errormsg/error.go#L28

Now in Goa 3.22 this global variable was removed: c0023b3#diff-a7bccd2240d1b5ac8c9932db99fc5aee8a4f45e81273ad7f2537a51fccec8f35

Can I get some advice how to correctly adjust the plugin?

[raphael]

Good question! This change was needed to enable JSON-RPC code generation where the HTTP expressions have to be modified in-situ. It was not possible to keep the global variable to avoid affecting the standard HTTP code generation. The set of HTTP services should now be computed on-demand from the root expression as follows:

import "goa.design/goa/v3/expr"
import "goa.design/goa/v3/codegen/service"
import httpcodegen "goa.design/goa/v3/http/codegen"

// ...
services := service.NewServicesData(expr.Root)
httpServices := httpcodegen.NewServicesData(services, expr.Root.API.HTTP)

see https://github.com/goadesign/goa/blob/v3/codegen/generator/transport.go for details.

Sorry about the breaking change!

[jachym-tousek-keboola]

Thanks! This seems to have helped. I ran into another issue afterwards but it's likely not directly related to this so I'll opened a separate discussion.

[jachym-tousek-keboola]

Okay unfortunately it doesn't actually work correctly... I have a second issue with 3.22 (#3825) but we can skip that for now.

Right now I'm trying to update to 3.21.5, adjusting the plugin like this: keboola/keboola-as-code@5cb007d
But even that doesn't work correctly. You see the plugin makes changes to some of the generated functions bodies:
https://github.com/keboola/keboola-as-code/blob/5cb007d6ba38368cce198f1ea9a0b09e71fcec25/internal/pkg/service/common/goaextension/errormsg/error.go#L39-L49
I double checked this code and everything in modifyTypeValidation still works fine.

However: the changes to t.ValidateDef don't make it into the actual generated files.

If I had to guess I'd say it's because I'm calling httpServices := httpgen.NewServicesData(services) and the httpServices instance I end modifying ends up being different than what is used for actually generating the files.

Basically I think I'd need to get the ServiceData instance used by transport.go. But there is no way to do that.

Is there some recommended way for plugins that want to modify the functionbodies like ValidateDef?

[jachym-tousek-keboola]

Managed to fix it by overriding Transport entirely. It isn't a nice solution but I don't see any alternative:
keboola/keboola-as-code@568b617

[raphael]

The suggestion above does not work for you?

services := service.NewServicesData(expr.Root)
httpServices := httpcodegen.NewServicesData(services, expr.Root.API.HTTP)

Note that both service and httpcodegen are package names so really this is all global.