Replace image property with data.read example. (#3)

* Delete `image` property from `ytt` rule.

README.md

@@ -35,12 +35,11 @@ load("@rules_ytt//:defs.bzl", "ytt")
 
 # Build an image with rules_docker
 
-load("@io_bazel_rules_docker//go:image.bzl", "go_image")
+load("@io_bazel_rules_docker//container:container.bzl", "container_image")
 
-go_image(
+container_image(
     name = "image",
-    srcs = ["main.go"],
-    importpath = "...",
+    ...
 )
 
 # or with rules_oci
@@ -60,24 +59,36 @@ ytt(
         ":base.yaml",
         ":defaults.yaml",
         ":values.yaml",
+        ":image.digest",
     ],
     # or
-    # srcs = glob(["*.yaml"]),
-    image = ":image.digest",
+    # srcs = glob(["*.yaml"]) + [":image.digest"],
 )
 ```
 
 Which is equivalent to
 
 ```shell
-ytt -f base.yaml -f defaults.yaml -f values.yaml --dangerous-allow-all-symlink-destinations
+ytt \
+    -f base.yaml \
+    -f defaults.yaml \
+    -f values.yaml \
+    -f image.json.sha256, # file created by "image.digest" target
+    --dangerous-allow-all-symlink-destinations
 ```
 
-* `bazel build //:manifests` - generates yaml files and store it in cache.
-* `bazel run //:manifests` - prints generated yaml files to stdout.
-* `bazel run //:manifests | kubectl -n <namespace> -f -` - applies generated manifests to k8s cluster.
+Inside YAML template digest can be used like this:
 
-Image digest is available inside yaml templates as `data.values.image_digest`.
+```yaml
+#@ load("@ytt:data", "data")
+---
+image: #@ "repo/image@" + data.read("image.json.sha256").strip()
+```
+### Commands
+
+* `bazel build //:manifests` - generates YAML files and retains them in cache.
+* `bazel run //:manifests` - prints generated YAML files to stdout.
+* `bazel run //:manifests | kubectl -n <namespace> -f -` - applies generated manifests to k8s cluster.
 
 ## LICENSE
 

docs/repositories.md

@@ -93,7 +93,7 @@ Users can avoid this macro and do these steps themselves, if they want more cont
 | Name  | Description | Default Value |
 | :------------- | :------------- | :------------- |
 | <a id="rules_ytt_register_toolchains-name"></a>name |  base name for all created repos, like "ytt"   |  <code>"ytt"</code> |
-| <a id="rules_ytt_register_toolchains-version"></a>version |  Ytt tool version. Supported versions are listed in <code>ytt/private/versions.bzl</code>.   |  <code>"0.46.2"</code> |
+| <a id="rules_ytt_register_toolchains-version"></a>version |  Ytt tool version. Supported versions are listed in [versions.bzl](/ytt/private/versions.bzl).   |  <code>"0.46.2"</code> |
 | <a id="rules_ytt_register_toolchains-kwargs"></a>kwargs |  passed to each node_repositories call   |  none |
 
 

docs/ytt.md

@@ -7,7 +7,7 @@
 ## ytt
 
 <pre>
-ytt(<a href="#ytt-name">name</a>, <a href="#ytt-image">image</a>, <a href="#ytt-srcs">srcs</a>)
+ytt(<a href="#ytt-name">name</a>, <a href="#ytt-srcs">srcs</a>)
 </pre>
 
 
@@ -18,7 +18,6 @@ ytt(<a href="#ytt-name">name</a>, <a href="#ytt-image">image</a>, <a href="#ytt-
 | Name  | Description | Type | Mandatory | Default |
 | :------------- | :------------- | :------------- | :------------- | :------------- |
 | <a id="ytt-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/concepts/labels#target-names">Name</a> | required |  |
-| <a id="ytt-image"></a>image |  (DEPRECATED) Target that generates a Docker image. Used for extracting image digest.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional | <code>None</code> |
-| <a id="ytt-srcs"></a>srcs |  List of files that will be passed to ytt with -f param.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | required |  |
+| <a id="ytt-srcs"></a>srcs |  List of files that will be passed to <code>ytt</code> with <code>-f</code> parameter.<br><br>      It could be <code>*.yaml</code> files as well as any other files which can be read       later form inside yaml template with       [data.read](https://carvel.dev/ytt/docs/v0.46.x/lang-ref-ytt/#data)       Starlark function. See [examples](/examples/minimal) for details.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | required |  |
 
 

examples/minimal/BUILD.bazel

@@ -1,8 +1,22 @@
 load("//:defs.bzl", "ytt")
 
+# genrule emulates an output for the following target:
+#
+# load("@rules_oci//oci:defs.bzl", "oci_image")
+#
+# oci_image(
+#     name = "image",
+#     ...
+# )
+genrule(
+  name = "image.digest",
+  outs = ["image.json.sha256"],
+  cmd = "echo sha256:ae59f3b71bffe15917f1b4e94218d1d46f21938ff1d1b2a04dfdf77f3763224e > $@",
+)
+
 ytt(
     name = "manifests",
-    srcs = glob(["*.yaml"]),
+    srcs = glob(["*.yaml"]) + [":image.digest"],
 )
 
 sh_library(

examples/minimal/base.yaml

@@ -3,3 +3,5 @@
 name: #@ data.values.name
 default: #@ data.values.default
 static: 1
+#! image.json.sha256 is a file created by image.digest target.
+image: #@ "repo/image@" + data.read("image.json.sha256").strip()

examples/minimal/validator.sh

@@ -1,7 +1,8 @@
 got="$(cat $1)"
 expected="name: YTT
 default: default value
-static: 1"
+static: 1
+image: repo/image@sha256:ae59f3b71bffe15917f1b4e94218d1d46f21938ff1d1b2a04dfdf77f3763224e"
 
 if [ "$got" = "$expected" ]; then
   echo "Passed"

ytt/private/ytt.bzl

@@ -1,40 +1,23 @@
 def _impl(ctx):
   ytt = ctx.toolchains["//ytt:toolchain_type"]
-  runtools = []
-  dv = []
-  runfiles = ctx.runfiles()
 
-  if ctx.file.image:
-    image_digest = ctx.actions.declare_file("image_digest.out")
-
-    ctx.actions.run_shell(
-      inputs = [ctx.file.image],
-      outputs = [image_digest],
-      command = "sed -e 's/^/image_digest: /g' {} > {}".format(ctx.file.image.path, image_digest.path),
-    )
-
-    runfiles = runfiles.merge(ctx.runfiles(files = [ctx.file.image, image_digest]))
-    runtools = [image_digest]
-    dv = ["--data-values-file", image_digest.path]
-
-  yttargs = ctx.actions.args()
-  yttargs.add("--dangerous-allow-all-symlink-destinations")
-  yttargs.add_all("", dv)
+  args = ctx.actions.args()
+  args.add("--dangerous-allow-all-symlink-destinations")
 
   for f in ctx.files.srcs:
-    yttargs.add("-f", f.path)
+    args.add("-f", f.path)
 
   manifest = ctx.actions.declare_file(ctx.label.name + ".yaml")
 
   ctx.actions.run_shell(
     inputs = ctx.files.srcs,
     outputs = [manifest],
-    arguments = [yttargs],
+    arguments = [args],
     command = "{ytt} $@ > {manifest}".format(
       ytt = ytt.ytt_info.binary.path,
       manifest = manifest.path,
     ),
-    tools =  [ytt.ytt_info.binary] + runtools,
+    tools =  [ytt.ytt_info.binary],
   )
 
   sh = ctx.actions.declare_file("{}_render.sh".format(ctx.label.name))
@@ -47,7 +30,7 @@ def _impl(ctx):
 
   return [DefaultInfo(
     files = depset([manifest]),
-    runfiles = runfiles.merge(ctx.runfiles(files = [manifest])),
+    runfiles = ctx.runfiles(files = [manifest]),
     executable = sh,
   )]
 
@@ -57,11 +40,13 @@ ytt = rule(
     "srcs": attr.label_list(
       allow_files = True,
       mandatory = True,
-      doc = "List of files that will be passed to ytt with -f param.",
-    ),
-    "image": attr.label(
-      allow_single_file = True,
-      doc = "(DEPRECATED) Target that generates a Docker image. Used for extracting image digest.",
+      doc = """List of files that will be passed to `ytt` with `-f` parameter.
+
+      It could be `*.yaml` files as well as any other files which can be read
+      later form inside yaml template with
+      [data.read](https://carvel.dev/ytt/docs/v0.46.x/lang-ref-ytt/#data)
+      Starlark function. See [examples](/examples/minimal) for details.
+      """
     ),
   },
   toolchains = ["//ytt:toolchain_type"],

ytt/repositories.bzl

@@ -97,7 +97,8 @@ def rules_ytt_register_toolchains(name = "ytt", version = "0.46.2", **kwargs):
 
     Args:
         name: base name for all created repos, like "ytt"
-        version: Ytt tool version. Supported versions are listed in `ytt/private/versions.bzl`.
+        version: Ytt tool version. Supported versions are listed in
+          [versions.bzl](/ytt/private/versions.bzl).
         **kwargs: passed to each node_repositories call
     """
     for platform in PLATFORMS.keys():