Added docker image building

MODULE.bazel

@@ -14,7 +14,7 @@ maven.install(
 use_repo(maven, "maven")
 
 bazel_dep(name = "rules_pkg", version = "1.0.1")
-bazel_dep(name = "rules_oci", version = "2.0.0")
+bazel_dep(name = "rules_oci", version = "2.0.1")
 
 oci = use_extension("@rules_oci//oci:extensions.bzl", "oci")
 oci.pull(

README.md

@@ -13,3 +13,24 @@ Formatting is tested in [CI](.github/workflows/pr.yml)
 **Comment**: Scalafmt is "goto" tool for formatting Scala code. Yet, included scalafmt in rules_scala is unnecessarily complicated. E.g. execution requires for all targets use `<TARGET>.format` which is hard to execute for all targets.
 That's why I decided to use [standalone](https://scalameta.org/scalafmt/docs/installation.html#standalone) version of scalafmt.
 Alternative can be [rules_lint](https://github.com/aspect-build/rules_lint)
+
+## Docker
+
+Docker images are build using rules_oci. 
+Each service build file has extension docker_image, which points to [oci.bzl](tools/oci.bzl)
+
+Local image build:
+```bash
+bazel run //projects/service-1/src/main:local_image
+```
+
+Local image test
+```bash
+docker run --rm service1:latest 
+```
+
+Push of image
+```bash
+bazel run //projects/service-1/src/main:push
+```
+

projects/service-1/src/main/BUILD.bazel

@@ -1,4 +1,4 @@
-scala_binary(
+scala_library(
     name = "service1",
     srcs = glob(["scala/**/*.scala"]),
     main_class = "com.org.service1.Service1App",
@@ -8,3 +8,9 @@ scala_binary(
     ],
     deps = ["//projects/commons/init-log/src/main:init-log"],
 )
+
+docker_image(
+    application_name = "service1",
+    main_class = "com.org.service1.Service1App",
+    deps = [":service1"],
+)

projects/service-2/src/main/BUILD.bazel

@@ -1,4 +1,4 @@
-scala_binary(
+scala_library(
     name = "service2",
     srcs = glob(["scala/**/*.scala"]),
     main_class = "com.org.service2.Service2App",
@@ -8,3 +8,9 @@ scala_binary(
     ],
     deps = ["//projects/commons/init-log/src/main:init-log"],
 )
+
+docker_image(
+    application_name = "service2",
+    main_class = "com.org.service2.Service2App",
+    deps = [":service2"],
+)

tools/build_rules/prelude_bazel

@@ -1,3 +1,4 @@
 # this file allows to load by default selected rules
 
 load("@io_bazel_rules_scala//scala:scala.bzl", "scala_test", "scala_binary", "scala_library")
+load("//tools:oci.bzl", "docker_image")

tools/oci.bzl

@@ -0,0 +1,31 @@
+load("@io_bazel_rules_scala//scala:scala.bzl", "scala_binary")
+load("@rules_oci//oci:defs.bzl", "oci_image", "oci_load", "oci_push")
+load("@rules_pkg//:pkg.bzl", "pkg_tar")
+
+def docker_image(application_name, main_class, deps = [], additional_jvm_opts = []):
+    return scala_binary(
+        name = "app",
+        main_class = main_class,
+        deps = deps,
+    ), pkg_tar(
+        name = "app_layer",
+        srcs = [":app_deploy.jar"],
+    ), oci_image(
+        name = "image",
+        base = "@java_temurin",
+        entrypoint = [
+            "java",
+        ] + additional_jvm_opts + [
+            "-jar",
+            "/app_deploy.jar",
+        ],
+        tars = [":app_layer"],
+    ), oci_load(
+        name = "local_image",
+        image = ":image",
+        repo_tags = ["{app}:latest".format(app = application_name)],
+    ), oci_push(
+        name = "push",
+        image = ":image",
+        repository = "docker.io/" + application_name,
+    )