From 96bedf16df480807ab04865db85a0b3c1eb2f470 Mon Sep 17 00:00:00 2001
From: Jason Hall <jasonhall@redhat.com>
Date: Tue, 14 Dec 2021 12:56:21 -0500
Subject: [PATCH] Add .ko.yaml to base ko container image on golang:1.17 (#533)

* Add .ko.yaml to base ko container image on golang:1.17

Ignore this in e2e tests, since even though golang:1.17 provides a
Windows base image, ko's base image platform selection doesn't take
osversion into account. The e2e tests don't exercise golang usage at
all, so it shouldn't matter.

* Update README
---
 .github/workflows/e2e.yaml | 3 +++
 .ko.yaml                   | 2 ++
 README.md                  | 4 +++-
 3 files changed, 8 insertions(+), 1 deletion(-)
 create mode 100644 .ko.yaml

diff --git a/.github/workflows/e2e.yaml b/.github/workflows/e2e.yaml
index 82d42f62be..a6b4f592cf 100644
--- a/.github/workflows/e2e.yaml
+++ b/.github/workflows/e2e.yaml
@@ -33,6 +33,9 @@ jobs:
         eval $(go env | sed -r 's/^(set )?(\w+)=("?)(.*)\3$/\2="\4"/gm')
 
         if [[ "${{ matrix.platform }}" == "windows-latest" ]]; then
+          # Always use the nanoserver base image, which matches the Windows
+          # version used by the GitHub Actions Windows runner.
+          rm .ko.yaml
           export KO_DEFAULTBASEIMAGE=mcr.microsoft.com/windows/nanoserver:1809
         fi
 
diff --git a/.ko.yaml b/.ko.yaml
new file mode 100644
index 0000000000..6371051bce
--- /dev/null
+++ b/.ko.yaml
@@ -0,0 +1,2 @@
+baseImageOverrides:
+  github.com/google/ko: golang:1.17
diff --git a/README.md b/README.md
index 614fd074f0..e0e81227c5 100644
--- a/README.md
+++ b/README.md
@@ -466,9 +466,11 @@ You can try out building a Windows container image by [setting the base image](#
 For example, to build a Windows container image for `ko`, from within this repo:
 
 ```
-KO_DEFAULTBASEIMAGE=mcr.microsoft.com/windows/nanoserver:1809 ko publish ./ --platform=windows/amd64
+ko publish ./ --platform=windows/amd64
 ```
 
+This works because the `ko` image is configured in [`.ko.yaml`](./.ko.yaml) to be based on a `golang` base image, which provides platform-specific images for both Linux and Windows.
+
 ### Known issues 🐛
 
 - Symlinks in `kodata` are ignored when building Windows images; only regular files and directories will be included in the Windows image.