try task + build

Taskfile.yml

@@ -1,8 +1,11 @@
 version: '3'
+
 env:
   IMAGE: jswank/alpine-cli
   NAME: alpine-cli
-  TAG: latest
+vars:
+  TAG:
+    sh: 'grep ^FROM Dockerfile  | cut -d: -f2'
 tasks:
   default:
     cmds:
@@ -13,3 +16,15 @@ tasks:
       - (podman manifest exists {{.IMAGE}}:{{.TAG}} && podman manifest rm {{.IMAGE}}:{{.TAG}}) || true
       - podman manifest create {{.IMAGE}}:{{.TAG}}
       - podman build --platform linux/amd64,linux/arm64 --manifest {{.IMAGE}}:{{.TAG}} {{.CLI_ARGS}} -f Dockerfile ctx
+  publish:
+    desc: publish the image
+    cmds:
+      - podman tag {{.IMAGE}}:{{.TAG}} {{.REGISTRY}}/{{.IMAGE}}:{{.ALT_TAG}}
+      - echo "${{.REGISTRY_PASS_VAR}}" | podman login {{.REGISTRY}} -u {{.REGISTRY_USER}} --password-stdin
+      - podman manifest push {{.REGISTRY}}/{{.IMAGE}}:{{.ALT_TAG}}
+      - podman logout {{.REGISTRY}}
+    vars:
+      REGISTRY_PASS_VAR: GH_PAT
+      REGISTRY: ghcr.io
+      REGISTRY_USER: jswank
+      ALT_TAG: '{{.TAG}}'