Spring to pick up git commit via Maven plugin or CI/CD variables (gitlab)

If you need a maven plugin that creates a properties file with the information taken from the .git directory, then use the git-commit-id maven plugin available from maven central.

Here is how I configured. At the initialise phase it reads the .git from the parent directory (we use a monorepo), then it generates a git.properties (that gets added into the classpath at target/classes/git.properties) with a specific list of git properties.

<plugin>
    <groupId>io.github.git-commit-id</groupId>
    <artifactId>git-commit-id-maven-plugin</artifactId>
    <version>5.0.0</version>
    <executions>
        <execution>
            <id>get-the-git-infos</id>
            <goals>
                <goal>revision</goal>
            </goals>
            <phase>initialize</phase>
        </execution>
    </executions>
    <configuration>
        <dotGitDirectory>${project.basedir}/../.git</dotGitDirectory>
        <verbose>false</verbose>
        <generateGitPropertiesFile>true</generateGitPropertiesFile>
        <generateGitPropertiesFilename>${project.build.outputDirectory}/git.properties
        </generateGitPropertiesFilename>
        <commitIdGenerationMode>full</commitIdGenerationMode>
        <includeOnlyProperties>
            <includeOnlyProperty>git.commit.id.abbrev</includeOnlyProperty>
            <includeOnlyProperty>git.commit.id.full</includeOnlyProperty>
            <includeOnlyProperty>git.commit.message.short</includeOnlyProperty>
            <includeOnlyProperty>git.commit.time</includeOnlyProperty>
        </includeOnlyProperties>
    </configuration>
</plugin>

I could then pick up the property file easily from Spring, as the file is in the classpath from the start.

package com.boardintelligence.writerapi.config;

import lombok.Data;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;

@Data
@Configuration
@PropertySource("classpath:git.properties")
public class GitCommitProperties {
    @Value("${git.commit.id.abbrev:na}")
    private String abbrev;

    @Value("${git.commit.id.full:na}")
    private String full;

    @Value("${git.commit.message.short:na}")
    private String messageShort;

    @Value("${git.commit.time:na}")
    private String time;
}

If the .git directory is not accessible from the CI/CD pipeline

If your pipeline builds the application without the .git directory (e.g. inside the docker container), you can add a src/main/resources/git.properties file with default values (and also more easily test its usage) and override it from the shell.

On Gitlab I’ve solved by adding some “before_script” commands to override that properties file with the available runner variables, just before the src are copied inside the container and the build starts

#.gitlab-ci.yml
your-task:
 before_script:
  - echo -n "git.commit.id.abbrev=${CI_COMMIT_SHORT_SHA}\ngit.commit.id.full=${CI_COMMIT_SHA}\ngit.commit.message.short=${CI_COMMIT_MESSAGE}\ngit.commit.time=${CI_COMMIT_TIMESTAMP}" > src/main/resources/git.properties

(I didn’t have time to find out how do it in one line, the “\n” was not recognised as a new line)