feat: stamp the "tag" attribute for oci_push (#59)

docs/docs.md

@@ -102,7 +102,7 @@ oci_pull(<a href="#oci_pull-name">name</a>, <a href="#oci_pull-digest">digest</a
 ## oci_push
 
 <pre>
-oci_push(<a href="#oci_push-name">name</a>, <a href="#oci_push-headers">headers</a>, <a href="#oci_push-manifest">manifest</a>, <a href="#oci_push-registry">registry</a>, <a href="#oci_push-repository">repository</a>, <a href="#oci_push-tag">tag</a>, <a href="#oci_push-x_meta_headers">x_meta_headers</a>)
+oci_push(<a href="#oci_push-name">name</a>, <a href="#oci_push-headers">headers</a>, <a href="#oci_push-manifest">manifest</a>, <a href="#oci_push-registry">registry</a>, <a href="#oci_push-repository">repository</a>, <a href="#oci_push-stamp">stamp</a>, <a href="#oci_push-tag">tag</a>, <a href="#oci_push-x_meta_headers">x_meta_headers</a>)
 </pre>
 
 
@@ -119,7 +119,8 @@ oci_push(<a href="#oci_push-name">name</a>, <a href="#oci_push-headers">headers<
 | <a id="oci_push-manifest"></a>manifest |  A manifest to push to a registry. If an OCILayout index, then                 push all artifacts with a 'org.opencontainers.image.ref.name'                 annotation.   | <a href="https://bazel.build/docs/build-ref.html#labels">Label</a> | optional | None |
 | <a id="oci_push-registry"></a>registry |  A registry host to push to, if not present consult the toolchain.   | String | optional | "" |
 | <a id="oci_push-repository"></a>repository |  A repository to push to, if not present consult the toolchain.   | String | optional | "" |
-| <a id="oci_push-tag"></a>tag |  (optional) A tag to include in the target reference. This will not be included on child images."   | String | optional | "" |
+| <a id="oci_push-stamp"></a>stamp |  Whether to encode build information into the output. Possible values:<br><br>    - <code>stamp = 1</code>: Always stamp the build information into the output, even in         [--nostamp](https://docs.bazel.build/versions/main/user-manual.html#flag--stamp) builds.         This setting should be avoided, since it is non-deterministic.         It potentially causes remote cache misses for the target and         any downstream actions that depend on the result.     - <code>stamp = 0</code>: Never stamp, instead replace build information by constant values.         This gives good build result caching.     - <code>stamp = -1</code>: Embedding of build information is controlled by the         [--[no]stamp](https://docs.bazel.build/versions/main/user-manual.html#flag--stamp) flag.         Stamped targets are not rebuilt unless their dependencies change.   | Integer | optional | -1 |
+| <a id="oci_push-tag"></a>tag |  (optional) A tag to include in the target reference. This will not be included on child images.<br><br>                Subject to [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables) and ["Make variable"](https://bazel.build/reference/be/make-variabmes) substitution.<br><br>                **Stamping**<br><br>                You can use values produced by the workspace status command in your tag. To do this write a script that prints key-value pairs separated by spaces, e.g.<br><br>                <pre><code>sh                 #!/usr/bin/env bash                 echo "STABLE_KEY1 VALUE1"                 echo "STABLE_KEY2 VALUE2"                 </code></pre><br><br>                You can reference these keys in <code>tag</code> using curly braces,<br><br>                <pre><code>python                 oci_push(                     name = "push",                     tag = "v1.0-{STABLE_KEY1}",                 )                 </code></pre>   | String | optional | "" |
 | <a id="oci_push-x_meta_headers"></a>x_meta_headers |  (optional) A list of key/values to to be sent to the registry as headers with an X-Meta- prefix.   | <a href="https://bazel.build/docs/skylark/lib/dict.html">Dictionary: String -> String</a> | optional | {} |
 
 

oci/BUILD.bazel

@@ -69,6 +69,7 @@ bzl_library(
     srcs = ["push.bzl"],
     visibility = ["//visibility:public"],
     deps = [
+        "@aspect_bazel_lib//lib:stamping",
         "@com_github_datadog_rules_oci//oci:debug_flag",
         "@com_github_datadog_rules_oci//oci:providers",
     ],

oci/providers.bzl

@@ -4,6 +4,7 @@ OCIReferenceInfo = provider(
         "registry": "the URI where the artifact is stored",
         "repository": "a namespace for an artifact",
         "tag": "a organizational reference within a repository",
+        "tag_file": "a file containing the organizational reference within a repository",
         "digest": "a file containing the digest of the artifact",
     },
 )

oci/push.bzl

@@ -1,3 +1,4 @@
+load("@aspect_bazel_lib//lib:stamping.bzl", "STAMP_ATTRS", "maybe_stamp")
 load("@com_github_datadog_rules_oci//oci:providers.bzl", "OCIDescriptor", "OCILayout", "OCIReferenceInfo")
 load("@com_github_datadog_rules_oci//oci:debug_flag.bzl", "DebugInfo")
 
@@ -11,7 +12,54 @@ def _oci_push_impl(ctx):
         repository = ctx.attr.repository,
     )
 
-    tag = ctx.expand_make_variables("tag", ctx.attr.tag, {})
+    tag_file = ctx.actions.declare_file("{name}.tag".format(name = ctx.label.name))
+    ctx.actions.write(
+        output = tag_file,
+        content = ctx.expand_make_variables("tag", ctx.attr.tag, {}),
+    )
+
+    stamp = maybe_stamp(ctx)
+    if stamp:
+        unstamped_tag_file = tag_file
+        tag_file = ctx.actions.declare_file("{name}.stamped.tag".format(name = ctx.label.name))
+
+        args = ctx.actions.args()
+        args.add_all([
+            unstamped_tag_file,
+            tag_file,
+            stamp.stable_status_file,
+            stamp.volatile_status_file,
+        ])
+
+        ctx.actions.run_shell(
+            inputs = [
+                unstamped_tag_file,
+                stamp.stable_status_file,
+                stamp.volatile_status_file,
+            ],
+            outputs = [
+                tag_file,
+            ],
+            arguments = [args],
+            command = """#!/usr/bin/env bash
+scratch=$(cat $1)
+shift
+
+out=$1
+shift
+
+for file in $@
+do
+    while read -r key value
+    do
+        # Replace the keys with their corresponding values in the scratch output
+        scratch=${scratch//\\{$key\\}/$value}
+    done <$file
+done
+
+>$out echo -n "$scratch"
+""",
+        )
 
     digest_file = ctx.actions.declare_file("{name}.digest".format(name = ctx.label.name))
     ctx.actions.run(
@@ -47,7 +95,7 @@ def _oci_push_impl(ctx):
         --layout-relative {root} \\
         --desc {desc} \\
         --target-ref {ref} \\
-        --parent-tag \"{tag}\" \\
+        --parent-tag \"$(cat {tag})\" \\
         {headers} \\
         {xheaders} \\
 
@@ -59,12 +107,12 @@ def _oci_push_impl(ctx):
             layout = layout.blob_index.short_path,
             desc = ctx.attr.manifest[OCIDescriptor].descriptor_file.short_path,
             ref = ref,
-            tag = tag,
             debug = str(ctx.attr._debug[DebugInfo].debug),
             headers = headers,
             xheaders = xheaders,
             post_scripts = "\n".join(["./" + hook.short_path for hook in toolchain.post_push_hooks]),
             digest = digest_file.short_path,
+            tag = tag_file.short_path,
         ),
         output = ctx.outputs.executable,
         is_executable = True,
@@ -73,14 +121,15 @@ def _oci_push_impl(ctx):
     return [
         DefaultInfo(
             runfiles = ctx.runfiles(
-                files = layout.files.to_list() +
-                        [toolchain.sdk.ocitool, ctx.attr.manifest[OCIDescriptor].descriptor_file, layout.blob_index, digest_file] + toolchain.post_push_hooks,
+                files = layout.files.to_list() + toolchain.post_push_hooks +
+                        [toolchain.sdk.ocitool, ctx.attr.manifest[OCIDescriptor].descriptor_file, layout.blob_index, digest_file, tag_file],
             ),
         ),
         OCIReferenceInfo(
             registry = ctx.attr.registry,
             repository = ctx.attr.repository,
             digest = digest_file,
+            tag_file = tag_file,
         ),
     ]
 
@@ -90,7 +139,7 @@ oci_push = rule(
     """,
     implementation = _oci_push_impl,
     executable = True,
-    attrs = {
+    attrs = dict({
         "manifest": attr.label(
             doc = """
                 A manifest to push to a registry. If an OCILayout index, then
@@ -111,7 +160,28 @@ oci_push = rule(
         ),
         "tag": attr.string(
             doc = """
-                (optional) A tag to include in the target reference. This will not be included on child images."
+                (optional) A tag to include in the target reference. This will not be included on child images.
+
+                Subject to [$(location)](https://bazel.build/reference/be/make-variables#predefined_label_variables) and ["Make variable"](https://bazel.build/reference/be/make-variabmes) substitution.
+
+                **Stamping**
+
+                You can use values produced by the workspace status command in your tag. To do this write a script that prints key-value pairs separated by spaces, e.g.
+
+                ```sh
+                #!/usr/bin/env bash
+                echo "STABLE_KEY1 VALUE1"
+                echo "STABLE_KEY2 VALUE2"
+                ```
+
+                You can reference these keys in `tag` using curly braces,
+
+                ```python
+                oci_push(
+                    name = "push",
+                    tag = "v1.0-{STABLE_KEY1}",
+                )
+                ```
             """,
         ),
         "headers": attr.string_dict(
@@ -128,7 +198,7 @@ oci_push = rule(
             default = "//oci:debug",
             providers = [DebugInfo],
         ),
-    },
+    }, **STAMP_ATTRS),
     provides = [
         OCIReferenceInfo,
     ],