Add website docs for image type

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

website/docs/image.md

@@ -0,0 +1,210 @@
+---
+title: Image
+---
+
+Image is a field in the DALEC spec that allows you to customize certain aspects
+of the produced image. The image field is an object with the following properties:
+
+- `base`: The image ref to use as the base for the output container. [Deprecated: use `bases` instead] [base section](#base)
+- `bases`: The list of base images to use as the base for the output container(s). [bases section](#bases)
+- `post`: The post processing for the image, such as symlinks. [post section](#post)
+- `labels`: The labels for the image. This is an optional field. [labels section](#labels)
+- `env`: The environment variables for the image. This is an optional field. [env section](#env)
+- `entrypoint`: The entrypoint for the image. This is an optional field. [entrypoint section](#entrypoint)
+- `cmd`: The command for the image. This is an optional field. [cmd section](#cmd)
+- `workdir`: The working directory for the image. This is an optional field. [workdir section](#workdir)
+- `user`: The user for the image. This is an optional field. [user section](#user)
+- `stop_signal`: The stop signal for the image. This is an optional field. [stop signal section](#stop-signal)
+- `volumes`: The volumes for the image. This is an optional field. [volumes section](#volumes)
+
+
+:::note
+The `base` field is deprecated. Use the `bases` field instead.
+
+For `bases`, the requested build target may not support multiple base images.
+In this cases the target will produce an error.
+
+Currently only `windowscross/container` supports multiple base images for the
+purpose of building for multiple windows versions.
+If multiple bases are provided with the same `os.version` value in the image
+platform, this may produce an error or at least unexpected results since images
+are keyed on the image platform metadata.
+:::
+
+With the exception of `base`, `bases`, and `post`, these fields are all used to
+merge with the configured (or default) base image(s).
+
+### Base
+
+The `base` field is used to specify the base image for the output container.
+
+Example:
+
+```yaml
+image:
+  base: mcr.microsoft.com/cbl-mariner/distroless/minimal:2.0
+```
+
+
+### Bases
+
+As noted above, the `bases` field is used to specify the base image(s) for the
+output container(s).
+Multiple bases can be specified for the same target, but the target must support
+it.
+Currently the only built-in target that supports this is `windowscross/container`
+where each base image specified is used to build for a different Windows version.
+
+
+Example:
+
+```yaml
+image:
+  bases:
+    - rootfs:
+        image:
+          ref: mcr.microsoft.com/cbl-mariner/distroless/minimal:2.0
+```
+
+The data type allows specifying any kind of [source](sources.md) for the base image,
+however currently only the `image` source is supported. Anything else will produce
+an error.
+Support for other source types may be added in the future.
+
+### Post
+
+The `post` field is used to specify post processing for the image.
+
+The following fields are supported:
+
+- `symlinks`: A list of symlinks to create in the image.
+
+Example:
+
+```yaml
+image:
+  post:
+    symlinks:
+      /usr/bin/my-binary: # Where the symlink points to
+        path: /my-binary # Where to place the symlink 
+```
+
+### Labels
+
+The `labels` field is used to specify labels for the image.
+
+Example:
+
+```yaml
+image:
+  labels:
+    com.example.label: example
+```
+
+### Env
+
+The `env` field is used to specify environment variables for the image.
+
+Example:
+
+```yaml
+image:
+  env:
+    - MY_ENV_VAR=my-value
+```
+
+### Entrypoint
+
+The `entrypoint` field is used to specify the entrypoint for the image.
+
+Example:
+
+```yaml
+image:
+  entrypoint: /usr/bin/my-binary
+```
+
+### Cmd
+
+The `cmd` field is used to specify the command for the image.
+
+Example:
+
+```yaml
+image:
+  cmd: /usr/bin/my-binary
+```
+
+### Workdir
+
+The `workdir` field is used to specify the working directory for the image.
+
+Example:
+
+```yaml
+image:
+  workdir: /my-dir
+```
+
+### User
+
+The `user` field is used to specify the user for the image.
+
+Example:
+
+```yaml
+image:
+  user: my-user:my-group
+```
+
+Alterantively
+
+```yaml
+image:
+  user: my-user
+```
+
+You may also use uid/gid values:
+
+```yaml
+image:
+  user: 1000:1000
+```
+
+Or just user:
+
+```yaml
+image:
+  user: 1000
+```
+
+User and group names are not automatically created for you, so it must be in
+the base OS to a username to work.
+
+### Stop Signal
+
+The `stop_signal` field is used to specify the stop signal for the image.
+This is used by the container runtime to know what signal to use to gracefully
+stop the container.
+
+Example:
+
+```yaml
+image:
+  stop_signal: SIGINT
+```
+
+### Volumes
+
+The `volumes` field is used to specify volumes for the image.
+
+Example:
+
+```yaml
+image:
+  volumes:
+    /some-path: {}
+```
+
+This is always a map of the path to create the volume at and an empty object.
+

website/docs/spec.md

@@ -107,8 +107,19 @@ For more information, please see [Targets](targets.md).
 
 Image section is used to define the base image and post processing for the image.
 
-- `base`: The base image for the target.
-- `post`: The post processing for the image, such as symlinks.
+Example:
+
+```yaml
+image:
+  base: mcr.microsoft.com/cbl-mariner/distroless/minimal:2.0
+  post:
+    symlinks:
+      /usr/bin/my-binary:
+       path: /my-binary
+  entrypoint: /my-binary
+```
+
+For more information, please see [Images](image.md).
 
 ### Package Config section