feat: #180 make the tarball target runnable (#290)

Co-authored-by: Alex Eagle <[email protected]>

docs/static_content.md

@@ -108,9 +108,7 @@ oci_image(
 ## Try running the container with docker
 
 ```bash
-# File created by running bazel build //frontend:frontend_tarball
-tarball_file=""
-docker load --input "$tarball_file"
+bazel run :frontend_tarball
 docker run --rm -p 8080:80 "ourfrontend:latest"
 ```
 

docs/tarball.md

@@ -15,8 +15,7 @@ oci_tarball(
 and then run it in a container like so:
 
 ```
-bazel build //path/to:tarball
-docker load --input $(bazel cquery --output=files //path/to:tarball)
+bazel run :tarball
 docker run --rm my-repository:latest
 ```
 

e2e/wasm/BUILD.bazel

@@ -46,8 +46,7 @@ build_test(
 
 # In order to run the image you need to follow instructions at https://docs.docker.com/desktop/wasm/ first.
 # then run the following;
-#  `bazel build :tarball`
-#  `docker load -i bazel-bin/tarball/tarball.tar`
+#  `bazel run :tarball``
 #  `docker run --runtime=io.containerd.wasmedge.v1 --platform=wasi/wasm32 --pull=never gcr.io/wasm:latest`
 oci_tarball(
     name = "tarball",

oci/private/BUILD.bazel

@@ -9,6 +9,7 @@ exports_files([
     "image.sh.tpl",
     "image_index.sh.tpl",
     "tarball.sh.tpl",
+    "tarball_run.sh.tpl",
     "push.sh.tpl",
 ])
 

oci/private/tarball.bzl

@@ -13,8 +13,7 @@ oci_tarball(
 and then run it in a container like so:
 
 ```
-bazel build //path/to:tarball
-docker load --input $(bazel cquery --output=files //path/to:tarball)
+bazel run :tarball
 docker run --rm my-repository:latest
 ```
 """
@@ -33,6 +32,13 @@ attrs = {
         allow_single_file = [".txt"],
         mandatory = True,
     ),
+    "_run_template": attr.label(
+        default = Label("//oci/private:tarball_run.sh.tpl"),
+        doc = """ \
+              The template used to load the container. The default template uses Docker, but this template could be replaced to use podman, runc, or another runtime. Please reference the default template to see available substitutions. 
+        """,
+        allow_single_file = True,
+    ),
     "_tarball_sh": attr.label(allow_single_file = True, default = "//oci/private:tarball.sh.tpl"),
 }
 
@@ -41,6 +47,7 @@ def _tarball_impl(ctx):
     tarball = ctx.actions.declare_file("{}/tarball.tar".format(ctx.label.name))
     yq_bin = ctx.toolchains["@aspect_bazel_lib//lib:yq_toolchain_type"].yqinfo.bin
     executable = ctx.actions.declare_file("{}/tarball.sh".format(ctx.label.name))
+    repo_tags = ctx.file.repo_tags
 
     substitutions = {
         "{{yq}}": yq_bin.path,
@@ -49,7 +56,7 @@ def _tarball_impl(ctx):
     }
 
     if ctx.attr.repo_tags:
-        substitutions["{{tags}}"] = ctx.file.repo_tags.path
+        substitutions["{{tags}}"] = repo_tags.path
 
     ctx.actions.expand_template(
         template = ctx.file._tarball_sh,
@@ -60,15 +67,26 @@ def _tarball_impl(ctx):
 
     ctx.actions.run(
         executable = executable,
-        inputs = [image, ctx.file.repo_tags],
+        inputs = [image, repo_tags],
         outputs = [tarball],
         tools = [yq_bin],
         mnemonic = "OCITarball",
         progress_message = "OCI Tarball %{label}",
     )
 
+    exe = ctx.actions.declare_file(ctx.label.name + ".sh")
+
+    ctx.actions.expand_template(
+        template = ctx.file._run_template,
+        output = exe,
+        substitutions = {
+            "{{image_path}}": tarball.short_path,
+        },
+        is_executable = True,
+    )
+
     return [
-        DefaultInfo(files = depset([tarball])),
+        DefaultInfo(files = depset([tarball]), runfiles = ctx.runfiles(files = [tarball]), executable = exe),
     ]
 
 oci_tarball = rule(
@@ -78,4 +96,5 @@ oci_tarball = rule(
     toolchains = [
         "@aspect_bazel_lib//lib:yq_toolchain_type",
     ],
+    executable = True,
 )

oci/private/tarball_run.sh.tpl

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+set -o pipefail -o errexit -o nounset
+
+readonly IMAGE="{{image_path}}"
+if command -v docker &> /dev/null; then
+    CONTAINER_CLI="docker"
+elif command -v podman &> /dev/null; then
+    CONTAINER_CLI="podman"
+else
+    echo >&2 "Neither docker or podman could be found."
+    echo >&2 "If you wish to use another container runtime, please comment on https://github.com/bazel-contrib/rules_oci/issues/295."
+    exit 1
+fi
+
+"$CONTAINER_CLI" load --input "$IMAGE"