Initial commit

skills/working-in-monorepos/scripts/monorepo-init

@@ -0,0 +1,203 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# monorepo-init: Auto-detect subprojects and generate .monorepo.json
+#
+# Usage:
+#   bin/monorepo-init              # Output JSON to stdout
+#   bin/monorepo-init --dry-run    # Same as above
+#   bin/monorepo-init --write      # Write to .monorepo.json
+
+show_usage() {
+  cat << EOF
+Usage: monorepo-init [OPTIONS]
+
+Auto-detect subprojects and generate .monorepo.json
+
+OPTIONS:
+  --dry-run    Output JSON to stdout (default)
+  --write      Write to .monorepo.json
+  -h, --help   Show this help
+
+DETECTION:
+  Scans for package manager artifacts:
+  - package.json (Node)
+  - Gemfile (Ruby)
+  - go.mod (Go)
+  - pyproject.toml, setup.py, requirements.txt (Python)
+  - Cargo.toml (Rust)
+  - build.gradle, pom.xml (Java)
+
+EXAMPLES:
+  bin/monorepo-init --dry-run
+  bin/monorepo-init | jq .
+  bin/monorepo-init --write
+EOF
+}
+
+# Parse arguments
+MODE="dry-run"
+while [[ $# -gt 0 ]]; do
+  case $1 in
+    --write)
+      MODE="write"
+      shift
+      ;;
+    --dry-run)
+      MODE="dry-run"
+      shift
+      ;;
+    -h | --help)
+      show_usage
+      exit 0
+      ;;
+    *)
+      echo "Unknown option: $1" >&2
+      show_usage >&2
+      exit 1
+      ;;
+  esac
+done
+
+# Find repo root
+find_repo_root() {
+  git rev-parse --show-toplevel 2> /dev/null || {
+    echo "Error: Not in a git repository" >&2
+    exit 1
+  }
+}
+
+# Detect subproject type from artifacts
+detect_type() {
+  local dir="$1"
+
+  if [[ -f "$dir/package.json" ]]; then
+    echo "node"
+  elif [[ -f "$dir/Gemfile" ]]; then
+    echo "ruby"
+  elif [[ -f "$dir/go.mod" ]]; then
+    echo "go"
+  elif [[ -f "$dir/pyproject.toml" ]] || [[ -f "$dir/setup.py" ]] || [[ -f "$dir/requirements.txt" ]]; then
+    echo "python"
+  elif [[ -f "$dir/Cargo.toml" ]]; then
+    echo "rust"
+  elif [[ -f "$dir/build.gradle" ]] || [[ -f "$dir/pom.xml" ]]; then
+    echo "java"
+  else
+    echo "unknown"
+  fi
+}
+
+# Find all artifact files
+find_artifacts() {
+  local root="$1"
+
+  # Check if fd is available (faster)
+  if command -v fd &> /dev/null; then
+    fd -t f '(package\.json|Gemfile|go\.mod|pyproject\.toml|setup\.py|requirements\.txt|Cargo\.toml|build\.gradle|pom\.xml)$' "$root"
+  else
+    # Fallback to find
+    find "$root" -type f \( \
+      -name 'package.json' -o \
+      -name 'Gemfile' -o \
+      -name 'go.mod' -o \
+      -name 'pyproject.toml' -o \
+      -name 'setup.py' -o \
+      -name 'requirements.txt' -o \
+      -name 'Cargo.toml' -o \
+      -name 'build.gradle' -o \
+      -name 'pom.xml' \
+      \)
+  fi
+}
+
+# Generate JSON structure
+generate_json() {
+  local root="$1"
+  local subprojects="$2" # newline-separated list of "id:path:type"
+
+  # Start JSON
+  cat << EOF
+{
+  "root": "$root",
+  "subprojects": {
+EOF
+
+  # Add each subproject
+  local first=true
+  while IFS=: read -r id path type; do
+    if [[ "$first" == true ]]; then
+      first=false
+    else
+      echo ","
+    fi
+
+    cat << EOF
+    "$id": {
+      "path": "$path",
+      "type": "$type"
+    }
+EOF
+  done <<< "$subprojects"
+
+  # Close JSON
+  cat << EOF
+
+  }
+}
+EOF
+}
+
+# Main logic
+REPO_ROOT=$(find_repo_root)
+cd "$REPO_ROOT"
+
+# Find all artifacts and group by directory
+declare -A seen_dirs
+SUBPROJECTS=""
+
+while read -r artifact_path; do
+  dir=$(dirname "$artifact_path")
+
+  # Skip if we've seen this directory
+  [[ -n "${seen_dirs[$dir]:-}" ]] && continue
+  seen_dirs[$dir]=1
+
+  # Generate subproject ID (relative path with / → -)
+  rel_path="${dir#$REPO_ROOT/}"
+  if [[ "$rel_path" == "$REPO_ROOT" ]] || [[ "$rel_path" == "." ]]; then
+    id="root"
+    rel_path="."
+  else
+    id="${rel_path//\//-}"
+  fi
+
+  # Detect type
+  type=$(detect_type "$dir")
+
+  # Add to list
+  SUBPROJECTS+="$id:$rel_path:$type"$'\n'
+done < <(find_artifacts "$REPO_ROOT")
+
+# Generate JSON
+JSON=$(generate_json "$REPO_ROOT" "$SUBPROJECTS")
+
+# Output based on mode
+case "$MODE" in
+  dry-run)
+    echo "$JSON"
+    ;;
+  write)
+    if [[ -f ".monorepo.json" ]]; then
+      echo "Warning: .monorepo.json already exists" >&2
+      echo "Overwrite? (y/N) " >&2
+      read -r response
+      if [[ ! "$response" =~ ^[Yy]$ ]]; then
+        echo "Aborted" >&2
+        exit 1
+      fi
+    fi
+    echo "$JSON" > .monorepo.json
+    echo "Written to .monorepo.json" >&2
+    ;;
+esac