Sign a specific APK with Bitrise's sign-apk Step

Bitrise (iOS & Android Build Automation), lets you automatically sign your apk files and offers you two options to achieve this: You either specify code sign configuration in your Gradle configuration, or you let sign-apk step sign your unsigned apk. Unfortunately, if you want to build more than one build variant or you have different platform variants or flavors, you can’t specify which apk the sign-apk step should pick up and sign. There is already an issue reported for support of multiple apk in android workflows.

For 3 3 5, I didn’t want to wait until Bitrise provides an out-of-box solution, but at the same time I wanted to:

  • Build a debug and a release apk,
  • Automatically sign the release apk during the build process,
  • Not specify sign configuration in Gradle configuration, and
  • Rename release-unsigned-bitrise-signed to a nicer name.

I came up with two little shell scripts I placed before and after the sign-apk step in the build workflow. The before script “Set APK path for signing” looks for the unsigned apk file and sets an environment variable with its file path.

# fail if any commands fails
set -e
# debug log
set -x

# find *unsigned*.apk in directory of BITRISE_APK_PATH
MY_APK_PATH=`find "\`dirname $BITRISE_APK_PATH\`" -type f -path "*unsigned*.apk" | head -n 1`

# add env var MY_APK_PATH
envman add --key MY_APK_PATH --value "$MY_APK_PATH"
echo "The unsigned apk path is now available in the environment variable: \$MY_APK_PATH (value: $MY_APK_PATH)"

# optional: print file info

# optional: replace BITRISE_APK_PATH
#envman add --key BITRISE_APK_PATH --value "$MY_APK_PATH"

In order to not surprise myself in the future, I set the environment variable $MY_APK_PATH which is then used in the sign-apk step as an input value:

sign-apk step apk path

The after script “Rename, remove APKs” cleans up the deploy directory after the sign-apk step.

# fail if any commands fails
set -e
# debug log
set -x

# rename apk using prename
#rename -V
# Error: Bareword "bitrise" not allowed while "strict subs" in use at (user-supplied code).
# Error: Bareword "signed" not allowed while "strict subs" in use at (user-supplied code).
#rename -v -- "-unsigned-bitrise-signed" "-signed" $BITRISE_DEPLOY_DIR/*.apk

# rename apk using mv
for i in $BITRISE_DEPLOY_DIR/*-unsigned-bitrise-signed.apk; do mv $i ${i/-unsigned-bitrise-signed/-bitrise-signed}; done

# remove unsigned apks
rm $BITRISE_DEPLOY_DIR/*unsigned*.apk

There was a little surprise when rename threw errors about not allowed words in a regular expression. Apperantly, rename on Debian is prename. The supplied expression is being executed as a perl script and there must be some conflict with imported libraries and symbols. Didn’t investigate that any further and instead used mv in a for loop.

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