API proxy struct codegen

[magik6k]

Includes #5844

The main part is just 300LOC in gen/api/proxygen.go, rest of the diff is moving permissions and codegen

Like docsgen, for now it's hardcoded for the api/ package, that will get fixed when porting to the versioned api

[magik6k]

Ah, openrpc was getting param names from the struct, which is why those files are now smaller - diff from master:

10c10
<       "description": "```go\nfunc (c *FullNodeStruct) BeaconGetEntry(ctx context.Context, epoch abi.ChainEpoch) (*types.BeaconEntry, error) {\n\treturn c.Internal.BeaconGetEntry(ctx, epoch)\n}\n```",
---
>       "description": "```go\nfunc (s *FullNodeStruct) BeaconGetEntry(p0 context.Context, p1 abi.ChainEpoch) (*types.BeaconEntry, error) {\n\treturn s.Internal.BeaconGetEntry(p0, p1)\n}\n```",
15c15
<           "name": "epoch",
---
>           "name": "p1",
66c66
<         "url": "https://github.com/filecoin-project/lotus/blob/master/api/apistruct/struct.go#L893"
---
>         "url": "https://github.com/filecoin-project/lotus/blob/master/api/apistruct/struct.go#L885"

[vyzo]

this looks good to me and it's definitely an improvement over having to do it by hand.

I suppose the v1 scaffolding will come at a later pr or is it planned for here?

[Kubuxu]

It was also my mistake re OpenRPC files, I through the 99% meant 99% smaller, it probably means 99% different.

[Kubuxu]

Let's squash as it doesn't build in the middle.