why does bazel copy resources from subdirectories to the top level of a jar

Question

So the BUILD structure are like below:

java:

/src/java/com/abc/code/Code.java

resources:

/src/resources/com/abc/code/application.properties

BUILD filegroups

filegroup(
    name = "properties",
    srcs = glob(["application.properties"])
    visibility = ["//visibility:public"],
)

BUILD of app use filegroups as resources/classpath_resources

java_binary(
    name = "app",
    classpath_resources = [
        "//src/resources/com/abc/code:properties",
    ],
    # resources = [
    #     "//src/resources/com/abc/code:properties",
    # ],
    main_class = "com.abc.code.Code",
    runtime_deps = [
        ":app_bin",
    ],
)

get null back for Code.class.getResourceAsStream("application.properties");

and after checking the generated jar, found that application.properties sits in the top /

jar tf poc_delivery_system_app.jar

META-INF/
META-INF/MANIFEST.MF
application.properties

then update the code to Code.class.getResourceAsStream("/application.properties"); which works,

The question is why application.properties is in the top level instead of something like /com/abc/code/application.properties

So the title of the question should be something like "why does bazel copy resources from subdirectories to the top level of a jar"? — tgdavies, Nov 09 '20 at 00:26
The documentation for `classpath_resources` says "A list of resources that must be located at the root of the java tree" (https://docs.bazel.build/versions/master/be/java.html#java_binary.classpath_resources). Are you sure you saw the same behavior using the `resources` attribute? — ahumesky, Nov 18 '20 at 18:27

score 1 · Answer 1 · answered Dec 16 '20 at 20:26

The resources have the following resource(s)

srcs = glob(["application.properties"])

So, indeed they are at the source.

If you want them in a subdirectory, place the BUILD file at $WORKSPACE/src/resources/BUILD with

filegroup(
  name = "resources",
  srcs = glob(["**/*.properties"]),
)

and the java lib will then

  resources = [
     "//src/resources",
  ],

why does bazel copy resources from subdirectories to the top level of a jar

1 Answers1