From 1bf0841574d228b86979c0235cda1d0b13bc2e00 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bojan=20=C4=8Cekrli=C4=87?= <bojan@cekrlic.com>
Date: Sat, 3 Oct 2020 14:02:33 +0200
Subject: [PATCH] Add proper docker tag detection

---
 .github/workflows/build-and-release.yml |  22 +-----
 get-docker-tags.sh                      | 101 ++++++++++++++++++++++++
 2 files changed, 102 insertions(+), 21 deletions(-)
 create mode 100755 get-docker-tags.sh

diff --git a/.github/workflows/build-and-release.yml b/.github/workflows/build-and-release.yml
index 10cebfc..69c987a 100644
--- a/.github/workflows/build-and-release.yml
+++ b/.github/workflows/build-and-release.yml
@@ -30,27 +30,7 @@ jobs:
         id: extract_tag_names
         if: startsWith(github.ref, 'refs/tags/') && github.event_name != 'pull_request'
         shell: bash
-        # TODO: This code assumes that the most recent tag pushed is also the latest version of the app.
-        # This might not always be the case. What we would nedd to do is check if there are any semver
-        # tags in front of us and if so, do not set the laster-major-minor docker tags approperiately.
-        #
-        # Quick Google search did not find anything useful on the topic.
-        run: |
-          export TAG="${GITHUB_REF:10}"
-          if [[ "$TAG" == v* ]]; then
-            # Remove "v" from the beginning
-            TAG=$(echo "$TAG" | cut -c2-)
-            export TAGS="-t boky/socketace:latest"
-            while [[ -n "$TAG" ]]; do
-              TAGS="$TAGS -t boky/socketace:$TAG"
-              TAG="$(echo "$TAG" | rev | cut -d. -f2- | rev)"
-            done
-            echo "::set-env name=TAGS::$TAGS"
-          else
-            echo "::set-env name=DO_BUILD_TAG::"
-          fi
-
-          echo "::set-env name=DO_BUILD_TAG::1"
+        run: ./get-docker-tags.sh
 
       - name: Build tagged version
         id: build_tagged_version
diff --git a/get-docker-tags.sh b/get-docker-tags.sh
new file mode 100755
index 0000000..7be988c
--- /dev/null
+++ b/get-docker-tags.sh
@@ -0,0 +1,101 @@
+#!/usr/bin/env bash
+
+#
+# Extract the data on which docker image tags should be built from the list of git tags
+#
+
+set -o errexit
+set -o pipefail
+set -o nounset
+
+declare TAG
+declare ALL_TAGS
+declare FOLLOWING_TAGS
+
+# version_weight converts the semver versions into a list which can be compared using `sort -V`
+version_weight () {
+  echo -e "$1" | tr ' ' "\n"  | sed -e 's:\+.*$::' | sed -e 's:^v::' | \
+  sed -Ee 's:^[0-9]+(\.[0-9]+)+$:&-stable:' | \
+  sed -Ee 's:([^A-Za-z])dev\.?([^A-Za-z]|$):\1.10.\2:g' | \
+  sed -Ee 's:([^A-Za-z])(alpha|a)\.?([^A-Za-z]|$):\1.20.\3:g' | \
+  sed -Ee 's:([^A-Za-z])(beta|b)\.?([^A-Za-z]|$):\1.30.\3:g' | \
+  sed -Ee 's:([^A-Za-z])(rc|RC)\.?([^A-Za-z]|$)?:\1.40.\3:g' | \
+  sed -Ee 's:([^A-Za-z])stable\.?([^A-Za-z]|$):\1.50.\2:g' | \
+  sed -Ee 's:([^A-Za-z])pl\.?([^A-Za-z]|$):\1.60.\2:g' | \
+  sed -Ee 's:([^A-Za-z])(patch|p)\.?([^A-Za-z]|$):\1.70.\3:g' | \
+  sed -E 's:\.{2,}:.:' | \
+  sed -E 's:\.$::' | \
+  sed -E 's:-\.:.:' | \
+  sed -E 's:^:v:'
+}
+
+
+# semversort will take a list of semantic versions and sort them properly. It takes a list of versions either
+# as list of arguments or as an input stream. One tag per line.
+# shellcheck disable=SC2120
+semversort() {
+  local -a tags_orig
+  local -a tags_weight
+  local -a versions_list
+  local -a keys
+
+  if [[ $# -gt 0 ]]; then
+    versions_list=$*
+  else
+    # catch pipeline output
+    versions_list=$(cat)
+  fi
+
+  # Map the tags into an array
+  mapfile -t tags_orig < <(echo "${versions_list}")
+
+  # Create a restructured list of versions which can be sorted
+  mapfile -t tags_weight < <(version_weight "${tags_orig[*]}")
+
+  # Calculate the key (index) values on the original array
+  keys=$(for ix in ${!tags_weight[*]}; do
+      printf "%s+%s\n" "${tags_weight[${ix}]}" "${ix}"
+  done | sort -V | cut -d+ -f2)
+
+  # Return data from the original array, sorted in ascending order
+  for ix in ${keys}; do
+      printf "%s\n" "${tags_orig[${ix}]}"
+  done
+}
+
+# Read the GitHub reference (we expect it to be in format "ref/tags/<tag-name>"
+TAG="${GITHUB_REF:10}"
+
+if [[ "$TAG" == v* ]]; then
+  # Get a list of all tags on the project, sort it by tag semantic version
+  ALL_TAGS="$(git tag -l | grep -E "^v*" | semversort)"
+
+  # Get a list of tags following our tag. List might be empty if this is the latest tag
+  FOLLOWING_TAGS="$(echo "$ALL_TAGS" | sed -e "1,/^${TAG}/ d")"
+
+  # Initialize the tag array
+  TAGS=""
+  if [[ -z "$FOLLOWING_TAGS" ]]; then
+    TAGS="-t boky/socketace:latest"
+  fi
+
+  # Gradually split the tag
+  # TODO: Also take into account that the tag may be followed by optional ["-" <pre-release>]["+" <build>]
+  while [[ -n "$TAG" ]]; do
+    if ! echo "${FOLLOWING_TAGS}" | grep -E -q "$TAG"; then
+      TAGS="$TAGS -t boky/socketace:$TAG"
+    fi
+    NEW_TAG="$(echo "$TAG" | rev | cut -d. -f2- | rev)"
+    if [[ "$NEW_TAG" == "$TAG" ]]; then
+      break
+    else
+      TAG="$NEW_TAG"
+    fi
+  done
+  echo "::set-env name=TAGS::$TAGS"
+else
+  echo "::set-env name=DO_BUILD_TAG::"
+fi
+
+echo "::set-env name=DO_BUILD_TAG::1"
+