This is an sbt plugin to help automate releases to Sonatype and Maven Central from Travis CI
- git tag pushes are published as regular releases to Maven Central
- merge into master commits are published as -SNAPSHOT with a unique version number for every commit
Beware that publishing from Travis CI requires you to expose Sonatype credentials as secret environment variables in Travis CI jobs. However, secret environment variables are not accessible during pull requests.
Let's get started!
First, follow the instructions in https://central.sonatype.org/pages/ossrh-guide.html to create a Sonatype account and make sure you have publishing rights for a domain name. This is a one-time setup per domain name.
If you don't have a domain name, you can use com.github.<@your_username>
. Here
is a template you can use to write the Sonatype issue:
Title:
Publish rights for com.github.olafurpg
Description:
Hi, I would like to publish under the groupId: com.github.olafurpg.
It's my GitHub account https://github.com/olafurpg/
If you prefer not to save your actual username and password in the Travis CI settings below, generate your user tokens:
- login to https://oss.sonatype.org,
- click your username in the top right, then profiles,
- in the tab that was opened, click on the top left dropdown, and select "User Token",
- click "Access User Token", and save the name and password parts of the token somewhere safe.
Next, install this plugin in project/plugins.sbt
// sbt 1 only, see FAQ for 0.13 support
addSbtPlugin("com.geirsson" % "sbt-ci-release" % "1.4.31")
By installing sbt-ci-release
the following sbt plugins are also brought in:
- sbt-dynver: sets the version number based on your git history
- sbt-pgp: to cryptographically sign the artifacts before publishing
- sbt-sonatype: to publish artifacts to Sonatype
- sbt-git: to automatically populate
scmInfo
Make sure build.sbt
does not define any of the following settings
version
: handled by sbt-dynverpublishTo
: handled by sbt-ci-releasepublishMavenStyle
: handled by sbt-ci-releasecredentials
: handled by sbt-sonatype
Next, define publishing settings at the top of build.sbt
inThisBuild(List(
organization := "com.geirsson",
homepage := Some(url("https://github.com/scalameta/sbt-scalafmt")),
licenses := List("Apache-2.0" -> url("http://www.apache.org/licenses/LICENSE-2.0")),
developers := List(
Developer(
"olafurpg",
"Ólafur Páll Geirsson",
"olafurpg@gmail.com",
url("https://geirsson.com")
)
)
))
Next, create a fresh gpg key that you will share with Travis CI and only use for this project.
gpg --gen-key
- For real name, use "$PROJECT_NAME bot". For example, in Scalafmt I use "Scalafmt bot"
- For email, use your own email address
- For passphrase, generate a random password with a password manager
At the end you'll see output like this
pub rsa2048 2018-06-10 [SC] [expires: 2020-06-09]
$LONG_ID
uid $PROJECT_NAME bot <$EMAIL>
Take note of $LONG_ID
, make sure to replace this ID from the code examples
below. The ID will look something like (a)
6E8ED79B03AD527F1B281169D28FC818985732D9
or something like (b)
A4C9 75D9 9C05 E4C7 2163 4BBD ACA8 EB32 0BFE FE2C
(in which case delete the
spaces to make it look like (a)). A command like this one should do:
LONG_ID=6E8ED79B03AD527F1B281169D28FC818985732D9
Next, copy the public gpg signature
# macOS
gpg --armor --export $LONG_ID | pbcopy
# linux
gpg --armor --export $LONG_ID | xclip
and post the signature to a keyserver: http://keyserver.ubuntu.com:11371/
- Select "Submit Key"
- Paste in the exported public key
- Click on "Submit Public Key".
Next, open the "Settings" panel for your project on Travis CI, for example https://travis-ci.org/scalameta/sbt-scalafmt/settings.
Make sure that "Build pushed branches" setting is enabled. Define four secret variables
PGP_PASSPHRASE
: The randomly generated password you used to create a fresh gpg key.PGP_SECRET
: The base64 encoded secret of your private key that you can export from the command line like here below
# macOS
gpg --armor --export-secret-keys $LONG_ID | base64 | pbcopy
# Ubuntu (assuming GNU base64)
gpg --armor --export-secret-keys $LONG_ID | base64 -w0 | xclip
# Arch
gpg --armor --export-secret-keys $LONG_ID | base64 | sed -z 's;\n;;g' | xclip -selection clipboard -i
# FreeBSD (assuming BSD base64)
gpg --armor --export-secret-keys $LONG_ID | base64 | xclip
SONATYPE_PASSWORD
: The password you use to log into https://oss.sonatype.org/. Alternatively, the password part of the user token if you generated one above. If the password contains bash special characters, make sure to escape it by wrapping it in single quotes'my?pa$$word'
, see Travis Environment Variables.SONATYPE_USERNAME
: The username you use to log into https://oss.sonatype.org/. Alternatively, the name part of the user token if you generated one above.- (optional)
CI_RELEASE
: the command to publish all artifacts for stable releases. Defaults to+publishSigned
if not provided. - (optional)
CI_SNAPSHOT_RELEASE
: the command to publish all artifacts for a SNAPSHOT releases. Defaults to+publish
if not provided. - (optional)
CI_SONATYPE_RELEASE
: the command called to close and promote the staged repository. Useful when, for example, also dealing with non-sbt projects to change tosonatypeReleaseAll
. Defaults tosonatypeBundleRelease
if not provided.
Next, update .travis.yml
to trigger ci-release
on successful merge into
master and on tag push. There are many ways to do this, but I recommend using
Travis "build stages". It's not
necessary to use build stages but they make it easy to avoid publishing the same
module multiple times from parallel jobs.
- First, ensure that git tags are always fetched so that sbt-dynver can pick up
the correct
version
before_install:
- git fetch --tags
- Next, define
test
andrelease
build stages
stages:
- name: test
- name: release
if: ((branch = master AND type = push) OR (tag IS present)) AND NOT fork
- Lastly, define your build matrix with
ci-release
at the bottom, for example:
jobs:
include:
# stage="test" if no stage is specified
- name: compile
script: sbt compile
- name: formatting
script: ./bin/scalafmt --test
# run ci-release only if previous stages passed
- stage: release
script: sbt ci-release
Notes:
- for a complete example of the Travis configuration, see the .travis.yml in this repository
- if we use
after_success
instead of build stages, we would runci-release
after bothformatting
andcompile
. As long as you make sure you don't publish the same module multiple times, you can use any Travis configuration you like - the
name: compile
part is optional but it makes it easy to distinguish different jobs in the Travis UI
We're all set! Time to manually try out the new setup
- Open a PR and merge it to watch the CI release a -SNAPSHOT version
- Push a tag and watch the CI do a regular release
git tag -a v0.1.0 -m "v0.1.0"
git push origin v0.1.0
Note that the tag version MUST start with v
.
It's is normal that something fails on the first attempt to publish from CI. Even if it takes 10 attempts to get it right, it's still worth it because it's so nice to have automatic CI releases. If all is correctly setup, your Travis jobs page will look like this:
Enjoy 👌
Add the following to the project settings (works only in sbt 1)
skip in publish := true
Make sure that projects that compile against multiple Scala versions declare the
crossScalaVersions
setting in build.sbt, for example
lazy val core = project.settings(
...
crossScalaVersions := List("2.13.1", "2.12.10", "2.11.12")
)
The command +publishSigned
(default value for CI_RELEASE
) will then publish
that project for 2.11, 2.12 and 2.13.
Yes! As soon as CI "closes" the staging repository you can depend on those artifacts with
resolvers += Resolver.sonatypeRepo("public")
(optional) Use the coursier command line interface to check if a release was successful without opening sbt
coursier fetch com.geirsson:scalafmt-cli_2.12:1.5.0 -r sonatype:public
Add the following setting
resolvers += Resolver.sonatypeRepo("snapshots")
(optional) With coursier you can do the same thing with -r sonatype:snapshots
coursier fetch com.geirsson:scalafmt-cli_2.12:1.5.0-SNAPSHOT -r sonatype:snapshots
You can try sbt-release-early.
Alternatively, the source code for sbt-ci-release is only ~50 loc, see
CiReleasePlugin.scala.
You can copy-paste it to project/
of your build and tweak the settings for
your environment.
Yes, but the plugin is not released for sbt 0.13. The plugin source code is a
single file which you can copy-paste into project/CiReleasePlugin.scala
of
your 0.13 build. Make sure you also
addSbtPlugin(sbt-dynver + sbt-sonatype + sbt-gpg + sbt-git)
.
You can publish sbt plugins to Maven Central like a normal library, no custom setup required. It is not necessary to publish sbt plugins to Bintray.
- Make sure you exported the correct
LONG_ID
for the gpg key. - Make sure the base64 exported secret GPG key is a single line (not line
wrapped). If you use the GNU coreutils
base64
(default on Ubuntu), pass in the-w0
flag to disable line wrapping.
java.io.IOException: PUT operation to URL https://oss.sonatype.org/content/repositories/snapshots 400: Bad Request
This error happens when you publish a non-SNAPSHOT version to the snapshot
repository. If you pushed a tag, make sure the tag version number starts with
v
. This error can happen if you tag with the version 0.1.0
instead of
v0.1.0
.
Make sure that SONATYPE_PASSWORD
uses proper escaping if it contains special
characters as documented on
Travis Environment Variables.
Make sure to upgrade to the latest sbt-ci-release, which could fix this error.
This failure can happen in case you push a git tag immediately after merging a
branch into master. A manual workaround is to log into https://oss.sonatype.org/
and drop the failing repository from the web UI. Alternatively, you can run
sonatypeDrop <staging-repo-id>
from the sbt shell instead of using the web UI.
Below is a non-exhaustive list of projects using sbt-ci-release. Don't see your project? Add it in a PR!
- almond-sh/almond
- coursier/coursier
- ekrich/sconfig
- olafurpg/metaconfig
- scala/sbt-scala-module
- scalacenter/scalafix
- scalameta/metabrowse
- scalameta/metals
- scalameta/scalafmt
- typelevel/paiges
- kubukoz/sup
- kubukoz/error-control
- kubukoz/vivalidi
- kubukoz/slick-effect
- kubukoz/flawless
There exist great alternatives to sbt-ci-release that may work better for your setup.
- sbt-ci-release-early: very similar to sbt-ci-release except doesn't use SNAPSHOT versions.
- sbt-release-early: additionally supports publishing to Bintray and other CI environments than Travis.
- sbt-rig: additionally supporting publishing code coverage reports, managing test dependencies and publishing docs.
The biggest difference between these and sbt-ci-release wrt to publishing is the
base64 encoded PGP_SECRET
variable. I never managed to get the encrypted files
and openssl working.