Update "example" keystore to instead be called "debug" and follow the debug.keystore format

[silbinarywolf]

What should this work do?

When using debug keystore we should attempt to locate $HOME/.android/debug.keystore as per Android API docs here. Failing finding it, we should consider trying to generate the debug key and placing it in this directory (if it exists)

What is the motivation?

We won't end up blowing away the keystore generated in .zig-cache anymore which means when developers delete .zig-cache and re-build / upload their APK to their Android devices, they won't need to run uninstall. So this will improve the developer user experience.

What should be changed?

• Add a new constant called debug (ie. const debug: CreateKey = ), this should use the example below as that follows Googles expected debug format. ie. What comes from using keytool
• Make const example: CreateKey point at debug and add a comment saying it is deprecated.
• Make debug first check for its own existence in the example directories listed below.
  • If it already exists, use it.
  • If it does not exist, create it in those folders.
    • ~/.android/ on OS X and Linux
    • C:\Users\user\.android\ on Windows Vista and Windows 7, 8, and 10
• update examples to use debug instead of deprecated example constant.
• update CreateKey name to KeyToolOptions
  • Make const CreateKey = KeyToolOptions that has a /// Deprecated: Use KeyToolOptions instead

Example of generating debug keystore

keytool -genkey -v -keystore debug.keystore -storepass android -alias androiddebugkey -keypass android -keyalg RSA -keysize 2048 -validity 10000

• Keystore name: "debug.keystore"
• Keystore password: "android"
• Key alias: "androiddebugkey"
• Key password: "android"
• CN: "CN=Android Debug,O=Android,C=US"

Example directories of debug.keystore

• ~/.android/ on OS X and Linux
• C:\Users\user\.android\ on Windows Vista and Windows 7, 8, and 10
• C:\Documents and Settings\user\.android\ on Windows XP

Android Keystore location and example output

These files were created by Android Studio after installing/running on Linux. You can make out that androiddebugkey is in the keystore file, so this is likely still the default way to generate a key.

Related resources

• https://developer.android.com/studio/publish/app-signing.html#debug-mode
• https://coderwall.com/p/r09hoq/android-generate-release-debug-keystores

[mark2185]

What should this work do?

When using debug keystore we should attempt to locate $HOME/.android/debug.keystore as per Android API docs here. Failing finding it, we should consider trying to generate the debug key and placing it in this directory (if it exists)

Is the debug keystore you're referring to the .example one? I.e. this one:

    pub const example: CreateKey = .{
        .alias = "default",
        .password = "example_password",
        .algorithm = .rsa,
        .key_size_in_bits = 4096,
        .validity_in_days = 10_000,
        .distinguished_name = "CN=example.com, OU=ID, O=Example, L=Doe, S=Jane, C=GB",
    };

Or should another such key be added, namely debug with the parameters you mentioned, and then when a createKeyStore is invoked it's checked if that's the debug key and use the existing one (or create it in ~/.android/ and use it)?

It sounds a bit iffy, that's why I want to discuss it first.

On that topic, what do you think about renaming CreateKey to KeyOptions or something similar?

[silbinarywolf]

@mark2185 Updated the issue above, but I want a new constant debug to use the Google-specified debug names like CN=Android Debug,O=Android,C=US for distinguished name. I'd also like example to point at debug and be deprecated.

As for renaming CreateKey, I think its a good idea. Perhaps KeyToolOptions? It is the options for running the command-line app keytool after all :)

[mark2185]

Wow, A for effort regarding the instructions, thanks!

Should the CreateKey symbol go through the deprecation lifecycle as well?

[silbinarywolf]

Should the CreateKey symbol go through the deprecation lifecycle as well?

Yeah, make that also deprecated as a comment please :)

[mark2185]

A few updates:

• this addOutputFileArg would create a "hook" that this apksigner could latch onto (at least that's my understanding, because modifying that file would invalidate the cache)
• I couldn't find a way to do the same with a file outside of the installation prefix (asked on discord as well), i.e. there is no way to move files outside the project root directory, addPrefixedOutputFileArg or addOutputFileArg both put it in .zig-cache
• there is the addFileInput for the apksigner side (as a "consumer") that can take an absolute path, but we don't have the corresponding equivalent for keystore side (as a "producer") so I used addArg on both ends
• however, since the keystore step gets created and goes out of scope in createKeyStore we have to somehow be able to link the two steps together
• I tried first adding it as a dependency for b.getInstallStep() and then when creating the apksigner iterate through the dependencies to find the key store dependency to add it to apksigner but that neither worked nor looked nice

At this point I figured it might be best to ask for help, so my questions are:

• is this even a viable option given the current build system API?
• should createKeyStore depend on the default install step by... default? Since it's only ever going to be run once (probably), each subsequent run will hit the initial if (alreadyExists). But I think this will also run into the problem of ordering of dependencies when building
• any ideas on how to progress?

I've pushed it all here, with the path to the debug.keystore hardcoded.