Adding script to get promotion paths from JSON map

iac/scripts/get-branch-promotions.sh

@@ -0,0 +1,126 @@
+#!/bin/sh
+
+# Function to display usage
+usage() {
+    echo "Usage: $0 [-h|--help] file.json [branch_name]"
+    echo ""
+    echo "Arguments:"
+    echo "  file.json           The JSON file to read promotion mappings from (required)."
+    echo "  branch_name         The branch name to check for promotion (optional). If not provided, the current Git branch will be used."
+    echo ""
+    echo "Flags:"
+    echo "  -h, --help          Show this help message and exit."
+    exit 0
+}
+
+# Function to handle error when no promotion branch is found
+error_exit() {
+    echo "No promotion branch for '$1'"
+    exit 1
+}
+
+# Function to handle error when no branch is found for reverse lookup
+error_from_exit() {
+    echo "No branch promotes to '$1'"
+    exit 1
+}
+
+# Function to retrieve promotion branch for a given key
+get_promotion() {
+    branch="$1"
+    jq_filter='.[$branch]'
+    promotion=$(cat "$json_file" | jq -r --arg branch "$branch" "$jq_filter")
+
+    if [ "$promotion" = "null" ] || [ -z "$promotion" ]; then
+        error_exit "$branch"
+    fi
+
+    echo "$promotion"
+}
+
+# Function to match branch using glob patterns
+match_branch() {
+    branch="$1"
+    cat "$json_file" | jq -r 'keys[]' | while read key; do
+        case "$branch" in
+            $key) echo "$key" && return 0 ;;
+        esac
+    done
+    return 1
+}
+
+# Function to handle promotion lookup based on the branch or glob pattern
+promotion_lookup() {
+    branch="$1"
+    matched_branch=$(match_branch "$branch")
+
+    if [ -z "$matched_branch" ]; then
+        error_exit "$branch"
+    fi
+
+    get_promotion "$matched_branch"
+}
+
+# Function to handle reverse lookup (finding branches that promote to the given one)
+reverse_lookup() {
+    branch="$1"
+    jq_filter='to_entries | map(select(.value == $branch)) | map(.key) | join(",")'
+    promotion_from=$(cat "$json_file" | jq -r --arg branch "$branch" "$jq_filter")
+
+    if [ -z "$promotion_from" ]; then
+        error_from_exit "$branch"
+    fi
+
+    echo "$promotion_from"
+}
+
+# Function to get the current Git branch
+get_current_git_branch() {
+    git rev-parse --abbrev-ref HEAD
+}
+
+# Parse command line arguments
+json_file=""
+branch=""
+help_flag=0
+
+while [ $# -gt 0 ]; do
+    case "$1" in
+        -h|--help)
+            help_flag=1
+            shift
+            ;;
+        *)
+            if [ -z "$json_file" ]; then
+                json_file="$1"
+            else
+                branch="$1"
+            fi
+            shift
+            ;;
+    esac
+done
+
+# Display help if -h or --help is passed
+if [ "$help_flag" -eq 1 ]; then
+    usage
+fi
+
+# Ensure a JSON file is supplied
+if [ -z "$json_file" ]; then
+    usage
+fi
+
+# If no branch is provided, get the current Git branch
+if [ -z "$branch" ]; then
+    branch=$(get_current_git_branch)
+fi
+
+# Commented out JSON map test data (kept for later use)
+# json_map='{"dev":"main","main":"prod","prod":null,"*[0-9]-*":"dev","hotfix":"prod"}'
+
+# Handle branch promotion logic or reverse lookup
+result=$(promotion_lookup "$branch")
+
+# Output result
+echo "$result"