Add tag.sh to tag a release

tag.sh

@@ -0,0 +1,178 @@
+#!/usr/bin/env bash
+
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+readonly PROGNAME=$(basename "$0")
+readonly PROGDIR=$(readlink -m "$(dirname "$0")")
+
+readonly EXCLUDE_PACKAGES="internal/tools"
+readonly SEMVER_REGEX="v(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)(\\-[0-9A-Za-z-]+(\\.[0-9A-Za-z-]+)*)?(\\+[0-9A-Za-z-]+(\\.[0-9A-Za-z-]+)*)?"
+
+usage() {
+    cat <<- EOF
+Usage: $PROGNAME [OPTIONS] SEMVER_TAG COMMIT_HASH
+
+Creates git tag for all Go packages in project.
+
+OPTIONS:
+  -h --help        Show this help.
+
+ARGUMENTS:
+  SEMVER_TAG       Semantic version to tag with.
+  COMMIT_HASH      Git commit hash to tag.
+EOF
+}
+
+cmdline() {
+    local arg commit
+
+    for arg
+    do
+        local delim=""
+        case "$arg" in
+            # Translate long form options to short form.
+            --help)           args="${args}-h ";;
+            # Pass through for everything else.
+            *) [[ "${arg:0:1}" == "-" ]] || delim="\""
+                args="${args}${delim}${arg}${delim} ";;
+        esac
+    done
+
+    # Reset and process short form options.
+    eval set -- "$args"
+
+    while getopts "h" OPTION
+    do
+         case $OPTION in
+         h)
+             usage
+             exit 0
+             ;;
+         *)
+             echo "unknown option: $OPTION"
+             usage
+             exit 1
+             ;;
+        esac
+    done
+
+    # Positional arguments.
+    shift $((OPTIND-1))
+    readonly TAG="$1"
+    if [ -z "$TAG" ]
+    then
+        echo "missing SEMVER_TAG"
+        usage
+        exit 1
+    fi
+    if [[ ! "$TAG" =~ $SEMVER_REGEX ]]
+    then
+        printf "invalid semantic version: %s\n" "$TAG"
+        exit 2
+    fi
+    if [[ "$( git tag --list "$TAG" )" ]]
+    then
+        printf "tag already exists: %s\n" "$TAG"
+        exit 2
+    fi
+
+    shift
+    commit="$1"
+    if [ -z "$commit" ]
+    then
+        echo "missing COMMIT_HASH"
+        usage
+        exit 1
+    fi
+    # Verify rev is for a commit and unify hashes into a complete SHA1.
+    readonly SHA="$( git rev-parse --quiet --verify "${commit}^{commit}" )"
+    if [ -z "$SHA" ]
+    then
+        printf "invalid commit hash: %s\n" "$commit"
+        exit 2
+    fi
+    if [ "$( git merge-base "$SHA" HEAD )" != "$SHA" ]
+    then
+        printf "commit '%s' not found on this branch\n" "$commit"
+        exit 2
+    fi
+}
+
+package_dirs() {
+    # Return a list of package directories in the form:
+    #
+    #  package/directory/a
+    #  package/directory/b
+    #  deeper/package/directory/a
+    #  ...
+    #
+    # Making sure to exclude any packages in the EXCLUDE_PACKAGES regexp.
+    find . -mindepth 2 -type f -name 'go.mod' -exec dirname {} \; \
+        | grep -E -v "$EXCLUDE_PACKAGES" \
+        | sed 's/^\.\///' \
+        | sort
+}
+
+git_tag() {
+    local tag="$1"
+    local commit="$2"
+
+    git tag -a "$tag" -s -m "Version $tag" "$commit"
+}
+
+previous_version() {
+    local current="$1"
+
+    # Requires git > 2.0
+    git tag -l --sort=v:refname \
+        | grep -E "^${SEMVER_REGEX}$" \
+        | grep -v "$current" \
+        | tail -1
+}
+
+print_changes() {
+    local tag="$1"
+    local previous
+
+    previous="$( previous_version "$tag" )"
+    if [ -n "$previous" ]
+    then
+        printf "\nRaw changes made between %s and %s\n" "$previous" "$tag"
+        printf "======================================\n"
+        git --no-pager log --pretty=oneline "${previous}..$tag"
+    fi
+}
+
+main() {
+    local dir
+
+    cmdline "$@"
+
+    cd "$PROGDIR" || exit 3
+
+    # Create tag for root package.
+    git_tag "$TAG" "$SHA"
+    printf "created tag: %s\n" "$TAG"
+
+    # Create tag for all sub-packages.
+    for dir in $( package_dirs )
+    do
+        git_tag "${dir}/$TAG" "$SHA"
+        printf "created tag: %s\n" "${dir}/$TAG"
+    done
+
+    print_changes "$TAG"
+}
+main "$@"