Make trezord-go usable as go library

[karelbilek]

To help other devs to use trezord-go as a library, I have added an api/ folder, which can be now used as a native golang API/library to contact Trezor devices.

To "test" the API properly, I have also modified the server/ to use directly the API, and not the core/ calls.

api.New(..) now also initializes all the USB libraries, to make the use easier; that was originally in main.go

I have also cleaned up the main.go a bit by breaking it into more files, when I was already rewriting it significantly

There are some caveats.

• I have intentionally made the API by copying the current HTTP calls and not making it more go-like; for example, Listen could be putting channel of devices instead of requiring previous, etc; basically because I want to "test" the new API calls by using it in the HTTP server itself.
• There is still no documentation :)
• There is no protobuf encoding/decoding, the API requires the user to do it themselves
• There might be a problem with the USB initialization in api.New, since the user of the API might already have LibUSB initialized and libusb requires to be initialized just once.
• There is no check if trezord-go is already running as a server. We should detect that and call that through HTTP if it already runs.
• I have NOT tested it with other software that already used trezord-go in a weird way as a library. The only one that I know of is rfjakob/gocryptfs which used it via xaionaro-go/cryptoWallet. Someone should look at and rewrite xaionaro-go/cryptoWallet and rfjakob/gocryptfs and send them PRs before merging this.

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The first commit is the addition of api/ and using it in server/ and trezord.go. The second commit is "just" moving everything except for api/ into internal/, so it cannot be linked directly by outside packages.

[karelbilek]

Ugh. I run gofmt -s, which simplified the code but made it incompatible with older go versions. I... don't know if that's something important or not

[karelbilek]

Also I broke fmt and metalinter. Hm. OK

[karelbilek]

github.com/conejoninja/tesoro/pb/messages has the protobuf messages, apparently

[karelbilek]

... github.com/conejoninja/tesoro seems to be another API for trezor, that partly uses our trezord-go code by copy-pasting it. Maybe we should look at that too and try to somehow fit trezord-go-as-a-library there

[karelbilek]

also CC @conejoninja , @xaionaro

[conejoninja]

... github.com/conejoninja/tesoro seems to be another API for trezor, that partly uses our trezord-go code by copy-pasting it. Maybe we should look at that too and try to somehow fit trezord-go-as-a-library there

Hi, it's been a while since I last touched tesoro, apart from websub, what other part seems to be copy-pasted? I'll remove them.

[karelbilek]

Hi, it's been a while since I last touched tesoro, apart from websub, what other part seems to be copy-pasted? I'll remove them

.Yeah I mean webusb :)

[karelbilek]

Hm another self-review: if this is meant to be used as an API, api/ (and therefore, internal/core/ and all the others) should not get memorywriter (which is our internal thing) as an option, just either io.Writer or *log.Logger. Which will be some rewriting too.

[karelbilek]

OK, now the library is actually trying to connect to bridge first and only then starts libusb. And from my short tests, it seems to be working.

Next steps: I will try to look at existing libraries/projects and try to use trezord-go/api there. Then add godoc documentation.

[karelbilek]

Looking at the other libraries - some of them have the ability to work in Android. That's interesting. Trezord-go probably doesn't work in Android, but I am not so sure - it's Linux under the hood - so maybe with some tiny changes, this would work as a library under Android.

[karelbilek]

I have tried to change Tesoro to use this new library, catched some bugs, but it seems working! (So it now works both with bridge, and if not installed, then with all 3 (~4) transports - hid, webusb, UDP emulator t2, UDP emulator for t1)

https://github.com/conejoninja/tesoro/compare/master...karel-3d:master

It will be similar to change the other libraries. (Note - android is probably not working.)

[karelbilek]

I have added documentation (which creates nice-ish godoc files) and also added protobuf messages, so it's all less annoying to use.

I needed to write my own code generation tool, because otherwise, it's error-prone to "by hand" put together messages.MessageType_MessageType_ButtonAck and the proto type messages.ButtonAck (because go doesn't allow you to find that).

What COULD I do is to use some more dynamic protobuf library, but that would mean losing the type safety, so... yeah I have added a lot of auto-generated code. To make using of this as a library simplier.

From me it's all here, I will also modify Tesoro and xaionaro-go to use the final version, I will NOT look into go-ethereum, which reimplements the same usb things AGAIN, but it could use this library too. If someone has mood/time :))))

[karelbilek]

OK, this is tesoro using the new library - not the PB serialization, since that would take just too much time (the code would be cleaner, but I don't have infinite time)

https://github.com/karel-3d/tesoro/commits/master

This is @xaionaro cryptowallet using the new library, INCLUDING the PB serialization (it was mostly deletions, as most of the code is not necessary anymore)

https://github.com/karel-3d/cryptoWallet/commit/add0f509eaaf803effad0a24312a5ddf98c2d7c4

The example for using the new library, which shows all the major functions (this is really all that is needed to integrate Trezor to golang app, no need for custom USB handling and custom protobuf magic in every integration)

https://github.com/karel-3d/trezord-go-2/blob/1699ab6f898e22460f0b73b9c8f885727f592266/trezorapi/transport_test.go

[karelbilek]

I am no longer updating this PR, and I would do it very differently this time (but still kept the auto-generation).

I will keep it here if someone wants to take over.