6 ms·

Go and Android

82 points by stickhandle 13y ago

pjmlp 13y ago
This is nothing more than a pure hack as it is not supported by Google and does not allow distribution via Play Store. The ticket for Go support is open since 2012, so clearly there isn't any interest from Android team to do so. https://code.google.com/p/android/issues/detail?id=39482 https://code.google.com/p/android/issues/detail?id=39482
- buffyreen 13y ago
  Someone on the Android team must be reading this, can someone make an official comment?
- RyanZAG 13y ago
  You didn't read his post to the end - you can include the Go binary into your normal Android app and then manually execute it. It certainly does allow distribution via Play Store and many apps currently available through the Play Store do similar things with Python and other languages. Many apps also use this method as a way to get around GPL'd code by distributing the GPL executable as a separate runnable application inside the .apk (.zip) file which allows their app to be closed source while containing GPL code.
  - pjmlp 13y ago
    > You didn't read his post to the end - you can include the Go binary into your normal Android app and then manually execute it. Yep, you are right, as I have seen too many of these workarounds. And what is the benefit? Bending ourselves just not to touch Java?! I rather be productive with the officially supported tools.
    - RyanZAG 13y ago
      I wouldn't confuse productive with officially supported - sometimes an unofficially supported tool can be far more productive. I agree completely with productive though. Anybody choosing a language for any reason but the quality of the output is just wasting their own time. Nobody really cares what language you used at the end of the day, only what you produce with it.
      - ithkuil 13y ago
        sometimes its just the fun. If I could write android apps in Go I would play with it, and perhaps I would get some ideas about what to build on mobile platforms.
    - vbsteven 13y ago
      It's not about avoiding Java, it's about not having to rewrite your already written Go code in Java. I've used both Tor and pjsip libraries (both written in C) this way.
      - pjmlp 13y ago
        > both written in C JNI
        coldtea 13y ago
        Of course, there's an answer for anything. But I'd take Gos FFI over JNI any day of the week. Plus, he also mentioned he has Go code he wanted to reuse.
- 4ad 13y ago
  There are Android apps in the Play Store that use Go extensively, e.g. Camlistore.
  - e12e 13y ago
    Thanks for the mention of Camlistore[1]. Wasn't aware of the project -- it seems to mirror many of the ideas I've been mulling about concerning storage. [1] http://camlistore.org/ http://camlistore.org/
mikhailt 13y ago
I'm not sure why Google hasn't adopted Go as another supported language to develop on Android. It seems naturally and would expand the usage of the language.
- ancarda 13y ago
  Go 1.3 is going to target android/arm: http://talks.golang.org/2014/go1.3.slide#12 http://talks.golang.org/2014/go1.3.slide#12. I'm not sure if this will lead to a full blown SDK for Android.
  - axaxs 13y ago
    Don't be mislead... this is just running on Android, which has long been possible. You still can't write/distribute a purely Go application in say, the play store.
  - aray 13y ago
    Android runs on more than just arm -- anything supported by the platform needs to support MIPS and x86 as well.
    - yebyen 13y ago
      It does have support, but I've seen exactly one MIPS droid (a budget tablet called a 'Cruz' that had great battery life and terrible performance) and zero x86 androids (other than ones I put together for myself from android-x86.org). So, I wouldn't say it needs to support these platforms. Just that not supporting them would be a glaring omission.
  - yla92 13y ago
    IMHO, it doesn't mean you can write for Android in go as much as you do in java.
- eurleif 13y ago
  Maintaining a Go wrapper for Android's Java APIs sounds non-trivial, and probably has security implications as well.
aray 13y ago
Every six months or so another way to run go code on android devices is published. Sometimes it's SDK wrappers, other times (like this) it's native executables. The author's approach is interesting, but lacks MIPS support (though would extend successfully to x86 devices, as the author notes). My almost equivalent attempt was to rebuild the Android NDK (native development kit) toolchain with --language=go added, and built all the GCC/GNU toolchain support for it for all targets. (Granted the rebuild-the-toolchain solution can be a bit hairy if you're not familiar with it.)
- justincormack 13y ago
  Yes MIPS support will be needed for an official solution I guess (at least there seems to be only one ABI spec for MIPS Android, o32, MIPS32r1). I really don't know how many MIPS Android devices there are out there.
habosa 13y ago
This is awesome, one of those posts that reminds me why I read HN so much. I'm an Android developer (they exist!) and I'll definitely try this out in my next app, just for fun. Anyone have any ideas for something I could do with this that I can't do, or do easily anyway, with a regular Java Android app?
kashif 13y ago
Dart is what is coming to Android with ART eventually - not Go.
- ahomescu1 13y ago
  Dart has nothing to do with ART, AFAIK. ART is an installation-time compiler for Dalvik binaries (essentially an AOT compiler for Java).
- oscargrouch 13y ago
  did you see something about this somewhere? care to share or elaborate? (im really curious) if thats is true, it means AOT compilation for Dart?
higherpurpose 13y ago
Would be nice if they started adding support for Go in Android 5.0, which won't be out until the end of the year at the very least.
dottrap 13y ago
Is there a way to build your Go stuff as a real, embeddable library and then call into it from C (via the NDK)? I think this would be a more natural way of doing it, and also be potentially more reusable on other platforms like iOS (which forbid launching processes). I would be interested in writing a simple HTTP server for my app in Go, and be able to invoke it (start, stop, etc) through a simple C-API. Then I could write the rest of the GUI in the native platform language (Java for Android, Objective-C for iOS).
- RyanZAG 13y ago
  I don't believe this would be possible as Go requires a runtime environment and garbage collection. If you called into a Go library through a function, you would need to manually set up the runtime environment and garbage collection before hand (and manage it). I think you'd be happier just using sockets to communicate with your Go process. I've done something similar before and it works well.
  - dottrap 13y ago
    So many languages allow doing this. Lua and Tcl are famous for this, but many other languages/runtimes also can do this, Python, Ruby, Javascript, C#, Java. They have a formal C API you can call through and define some memory management policy you need to conform to to interact with the garbage collector. This is pretty common stuff, albeit that some languages are much harder to embed than others. As I said, spawning processes and IPC isn't an option on all platforms. Are you sure Go doesn't have this ability?
    - icebraining 13y ago
      You can call Go from C, but the process main entry point must still be Go's, since that's the only way to launch its runtime. So technically you could embed it, but then you wouldn't be able to do any allocations or running goroutines.
DominikR 13y ago
Using the NDK is already such a pain in the ass (we are using pjsip in some of our apps) that I couldn't imagine why I would want to switch from C to Go, which isn't even officially supported. And you have to consider that soon everyone will switch to the Gradle build system, which adds amazing possibilities, but also adds a lot of complexity with build types and product flavors on top of the existing complexity with the NDK.
d0ugie 13y ago
Hey Microsoft, if you want to blow my mind and have a good chuckle, implement Go into the Windows Phone NDK before Google does with Android's.
- camus2 13y ago
  Why would Microsoft in their right mind do that? unless you port go to the CLR,it's not going to happen.

82 points by stickhandle 13y ago

pjmlp 13y ago

This is nothing more than a pure hack as it is not supported by Google and does not allow distribution via Play Store. The ticket for Go support is open since 2012, so clearly there isn't any interest from Android team to do so. https://code.google.com/p/android/issues/detail?id=39482 https://code.google.com/p/android/issues/detail?id=39482

buffyreen 13y ago
Someone on the Android team must be reading this, can someone make an official comment?
RyanZAG 13y ago
You didn't read his post to the end - you can include the Go binary into your normal Android app and then manually execute it. It certainly does allow distribution via Play Store and many apps currently available through the Play Store do similar things with Python and other languages. Many apps also use this method as a way to get around GPL'd code by distributing the GPL executable as a separate runnable application inside the .apk (.zip) file which allows their app to be closed source while containing GPL code.
- pjmlp 13y ago
  > You didn't read his post to the end - you can include the Go binary into your normal Android app and then manually execute it. Yep, you are right, as I have seen too many of these workarounds. And what is the benefit? Bending ourselves just not to touch Java?! I rather be productive with the officially supported tools.
  - RyanZAG 13y ago
    I wouldn't confuse productive with officially supported - sometimes an unofficially supported tool can be far more productive. I agree completely with productive though. Anybody choosing a language for any reason but the quality of the output is just wasting their own time. Nobody really cares what language you used at the end of the day, only what you produce with it.
    - ithkuil 13y ago
      sometimes its just the fun. If I could write android apps in Go I would play with it, and perhaps I would get some ideas about what to build on mobile platforms.
  - vbsteven 13y ago
    It's not about avoiding Java, it's about not having to rewrite your already written Go code in Java. I've used both Tor and pjsip libraries (both written in C) this way.
    - pjmlp 13y ago
      > both written in C JNI
      - coldtea 13y ago
        Of course, there's an answer for anything. But I'd take Gos FFI over JNI any day of the week. Plus, he also mentioned he has Go code he wanted to reuse.
4ad 13y ago
There are Android apps in the Play Store that use Go extensively, e.g. Camlistore.
- e12e 13y ago
  Thanks for the mention of Camlistore[1]. Wasn't aware of the project -- it seems to mirror many of the ideas I've been mulling about concerning storage. [1] http://camlistore.org/ http://camlistore.org/

mikhailt 13y ago

I'm not sure why Google hasn't adopted Go as another supported language to develop on Android. It seems naturally and would expand the usage of the language.

ancarda 13y ago
Go 1.3 is going to target android/arm: http://talks.golang.org/2014/go1.3.slide#12 http://talks.golang.org/2014/go1.3.slide#12. I'm not sure if this will lead to a full blown SDK for Android.
- axaxs 13y ago
  Don't be mislead... this is just running on Android, which has long been possible. You still can't write/distribute a purely Go application in say, the play store.
- aray 13y ago
  Android runs on more than just arm -- anything supported by the platform needs to support MIPS and x86 as well.
  - yebyen 13y ago
    It does have support, but I've seen exactly one MIPS droid (a budget tablet called a 'Cruz' that had great battery life and terrible performance) and zero x86 androids (other than ones I put together for myself from android-x86.org). So, I wouldn't say it needs to support these platforms. Just that not supporting them would be a glaring omission.
- yla92 13y ago
  IMHO, it doesn't mean you can write for Android in go as much as you do in java.
eurleif 13y ago
Maintaining a Go wrapper for Android's Java APIs sounds non-trivial, and probably has security implications as well.

aray 13y ago

Every six months or so another way to run go code on android devices is published. Sometimes it's SDK wrappers, other times (like this) it's native executables. The author's approach is interesting, but lacks MIPS support (though would extend successfully to x86 devices, as the author notes). My almost equivalent attempt was to rebuild the Android NDK (native development kit) toolchain with --language=go added, and built all the GCC/GNU toolchain support for it for all targets. (Granted the rebuild-the-toolchain solution can be a bit hairy if you're not familiar with it.)

justincormack 13y ago
Yes MIPS support will be needed for an official solution I guess (at least there seems to be only one ABI spec for MIPS Android, o32, MIPS32r1). I really don't know how many MIPS Android devices there are out there.

habosa 13y ago

This is awesome, one of those posts that reminds me why I read HN so much. I'm an Android developer (they exist!) and I'll definitely try this out in my next app, just for fun. Anyone have any ideas for something I could do with this that I can't do, or do easily anyway, with a regular Java Android app?

kashif 13y ago

Dart is what is coming to Android with ART eventually - not Go.

ahomescu1 13y ago
Dart has nothing to do with ART, AFAIK. ART is an installation-time compiler for Dalvik binaries (essentially an AOT compiler for Java).
oscargrouch 13y ago
did you see something about this somewhere? care to share or elaborate? (im really curious) if thats is true, it means AOT compilation for Dart?

higherpurpose 13y ago

Would be nice if they started adding support for Go in Android 5.0, which won't be out until the end of the year at the very least.

dottrap 13y ago

Is there a way to build your Go stuff as a real, embeddable library and then call into it from C (via the NDK)? I think this would be a more natural way of doing it, and also be potentially more reusable on other platforms like iOS (which forbid launching processes). I would be interested in writing a simple HTTP server for my app in Go, and be able to invoke it (start, stop, etc) through a simple C-API. Then I could write the rest of the GUI in the native platform language (Java for Android, Objective-C for iOS).

RyanZAG 13y ago
I don't believe this would be possible as Go requires a runtime environment and garbage collection. If you called into a Go library through a function, you would need to manually set up the runtime environment and garbage collection before hand (and manage it). I think you'd be happier just using sockets to communicate with your Go process. I've done something similar before and it works well.
- dottrap 13y ago
  So many languages allow doing this. Lua and Tcl are famous for this, but many other languages/runtimes also can do this, Python, Ruby, Javascript, C#, Java. They have a formal C API you can call through and define some memory management policy you need to conform to to interact with the garbage collector. This is pretty common stuff, albeit that some languages are much harder to embed than others. As I said, spawning processes and IPC isn't an option on all platforms. Are you sure Go doesn't have this ability?
  - icebraining 13y ago
    You can call Go from C, but the process main entry point must still be Go's, since that's the only way to launch its runtime. So technically you could embed it, but then you wouldn't be able to do any allocations or running goroutines.

DominikR 13y ago

Using the NDK is already such a pain in the ass (we are using pjsip in some of our apps) that I couldn't imagine why I would want to switch from C to Go, which isn't even officially supported. And you have to consider that soon everyone will switch to the Gradle build system, which adds amazing possibilities, but also adds a lot of complexity with build types and product flavors on top of the existing complexity with the NDK.

d0ugie 13y ago

Hey Microsoft, if you want to blow my mind and have a good chuckle, implement Go into the Windows Phone NDK before Google does with Android's.

camus2 13y ago
Why would Microsoft in their right mind do that? unless you port go to the CLR,it's not going to happen.