Error when loading rules_oci image tarball into docker

[AttilaTheFun]

Hi! I'm trying to build my docker images from my Go project with rules_oci. I tried following your guide, but I'm getting an error when attempting to load the tarball into docker.

My tarball target has the repotags set:

go_binary(
    name = "phono",
    embed = [":phono_lib"],
    visibility = ["//visibility:public"],
)

pkg_tar(
    name = "phono_tarball",
    srcs = [":phono"],
)

oci_image(
    name = "phono_image",
    architecture = select({
        "@platforms//cpu:arm64": "arm64",
        "@platforms//cpu:x86_64": "amd64",
    }),
    base = "@distroless_base",
    tars = [":phono_tarball"],
    entrypoint = ["/app"],
    os = "linux",
)

oci_tarball(
    name = "phono_image_tarball",
    image = ":phono_image",
    repotags = ["phono:latest"],
)

But I'm getting this error when running:

$ docker load --input /private/var/tmp/_bazel_logan/6935840e8ee73f156f0328fbaa27d52a/execroot/__main__/bazel-out/darwin_arm64-fastbuild/bin/apps/phono/phono_image_tarball/tarball.tar
json: cannot unmarshal string into Go struct field manifestItem.RepoTags of type []string

Note that I'm using a bazel symlink prefix in my .bazelrc:

build --symlink_prefix=.bazel/

So I had to use a shell script to construct the full path to the tar:

#!/bin/zsh

# Get the file path of the image tarball:
OCI_IMAGE_TARBALL_RELATIVE_FILE_PATH=$(bazel cquery --output=files $1)

# Trim off the bazel-out prefix:
OCI_IMAGE_TARBALL_RELATIVE_FILE_PATH=${OCI_IMAGE_TARBALL_RELATIVE_FILE_PATH#"bazel-out"}

# Get the path to the bazel-out directory at the destination of our symlink:
BAZEL_OUT_DIR_PATH=$(readlink -f .bazel/out)

# Concatenate the two together to get an absolute path to the image tarball:
OCI_IMAGE_TARBALL_ABSOLUTE_FILE_PATH=$BAZEL_OUT_DIR_PATH$OCI_IMAGE_TARBALL_RELATIVE_FILE_PATH

# Load the image into docker:
docker load --input $OCI_IMAGE_TARBALL_ABSOLUTE_FILE_PATH

I was able to work around the issue by using docker import instead and providing the tag manually but this is less than ideal:

cat /private/var/tmp/_bazel_logan/6935840e8ee73f156f0328fbaa27d52a/execroot/__main__/bazel-out/darwin_arm64-fastbuild/bin/apps/phono/phono_image_tarball/tarball.tar | docker import - phono:latest

Do you have any suggestions?

[AttilaTheFun]

I put up a PR to fix the bug here:
#190

[jmhodges]

I think this can be closed now that #205 has merged?

[AttilaTheFun]

Hi @jmhodges yes my PR fixed it. I’ll close it now.