Add make publish: build the image on the Docker host and push it to the registry

script/publish runs script/docker with DOCKER_HOST set to the Docker
host (ssh://root@fsn1app1 unless set) and pushes the image to
git.eeqj.de/sneak/smallwebwaf under four tags: the UTC date as
YYYY-MM-DD, the short commit hash, the branch name and latest. It
refuses a working tree with uncommitted changes, since the hash tag
names a commit.

Makefile

@@ -1,5 +1,5 @@
-.PHONY: bootstrap setup test lint fmt fmt-check tidy check docker hooks build \
-	run example-app gitea-requests gitea-setup
+.PHONY: bootstrap setup test lint fmt fmt-check tidy check docker publish \
+	hooks build run example-app gitea-requests gitea-setup
 
 # Makefile targets are thin shims; the implementations live in script/
 # per the scripts-to-rule-them-all pattern (see the Entrypoints section
@@ -7,7 +7,8 @@
 # which test checks. build and run are for working on the code by hand;
 # example-app checks the image with an app built on it; gitea-requests
 # reports the gitea requests the Core Rule Set refuses at the defaults;
-# gitea-setup checks the setup in deploy/gitea.
+# gitea-setup checks the setup in deploy/gitea; publish builds the image
+# on the Docker host and pushes it to the registry.
 
 bootstrap:
 	@script/bootstrap
@@ -36,6 +37,9 @@ check:
 docker:
 	@script/docker
 
+publish:
+	@script/publish
+
 hooks:
 	@script/install-precommit
 

README.md

@@ -743,6 +743,11 @@ on the host.
   `make check`.
 - `script/docker`: builds the image, whose build runs the tests and the linter
   first. `make docker`.
+- `script/publish`: runs `script/docker` on the Docker host `DOCKER_HOST`
+  (`ssh://root@fsn1app1` unless set) and pushes the image to `PUBLISH_IMAGE`
+  (`git.eeqj.de/sneak/smallwebwaf` unless set) under four tags: the UTC date as
+  `YYYY-MM-DD`, the short commit hash, the branch name and `latest`. Refuses a
+  working tree with uncommitted changes. `make publish`.
 - `script/cibuild`: what CI runs: `script/bootstrap`, `script/check`, then the
   image build.
 - `script/precommit`: run by the git pre-commit hook; runs `script/check`.

script/publish

@@ -0,0 +1,51 @@
+#!/bin/sh
+# script/publish: build the image on the Docker host and push it to the
+# registry under four tags: the UTC date (YYYY-MM-DD), the short commit
+# hash, the branch name and latest. The build is script/docker's, so the
+# tests and the linter run first. The host and the registry name are
+# environment variables with defaults, for running it against another.
+#
+# The working tree must be clean: the hash tag names a commit, and an
+# image built from uncommitted changes would carry a hash that does not
+# describe it.
+set -eu
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
+
+: "${DOCKER_HOST:=ssh://root@fsn1app1}"
+: "${PUBLISH_IMAGE:=git.eeqj.de/sneak/smallwebwaf}"
+export DOCKER_HOST
+
+main() {
+    cd "$ROOT"
+
+    if [ -n "$(git status --porcelain)" ]; then
+        echo "script/publish: the working tree is not clean; commit or stash first" >&2
+        exit 1
+    fi
+
+    date="$(date -u +%Y-%m-%d)"
+    hash="$(git rev-parse --short HEAD)"
+    branch="$(git rev-parse --abbrev-ref HEAD)"
+    if [ "$branch" = "HEAD" ]; then
+        echo "script/publish: detached HEAD; check out a branch first" >&2
+        exit 1
+    fi
+    # A tag is [A-Za-z0-9_.-]; a branch name such as feature/x is not.
+    branch="$(printf '%s' "$branch" | tr -c 'A-Za-z0-9_.-' '-')"
+
+    local_tag="$("$SCRIPT_DIR/projectname")"
+    "$SCRIPT_DIR/docker"
+
+    for tag in "$date" "$hash" "$branch" latest; do
+        docker tag "$local_tag" "$PUBLISH_IMAGE:$tag"
+    done
+    for tag in "$date" "$hash" "$branch" latest; do
+        docker push "$PUBLISH_IMAGE:$tag"
+    done
+
+    echo "pushed $PUBLISH_IMAGE with tags: $date $hash $branch latest"
+}
+
+main "$@"