Makefile Generator

Overview

Generate production-ready Makefiles with best practices for C/C++, Python, Go, Java, and generic projects. Features GNU Coding Standards compliance, standard targets, security hardening, and automatic validation via devops-skills:makefile-validator skill.

When to Use

• Creating new Makefiles from scratch
• Setting up build systems for projects (C/C++, Python, Go, Java)
• Implementing build automation and CI/CD integration
• Converting manual build processes to Makefiles
• The user asks to "create", "generate", or "write" a Makefile

Do NOT use for: Validating existing Makefiles (use devops-skills:makefile-validator), debugging (use make -d), or running builds.

Generation Workflow

Stage 1: Gather Requirements

Collect information for the following categories. Use AskUserQuestion when information is missing or ambiguous:

When to Use AskUserQuestion: MUST ask when language unspecified, project structure unclear, Docker registry unknown, multiple binaries possible, install paths unclear, or cross-compilation mentioned. Example questions: "What programming language?", "Single or multi-directory project?", "Which container registry?", "Target platform/architecture?"

Skip when: User provides all info explicitly, standard project with obvious defaults (e.g., "Go project with Docker"), or user says "use defaults".

Default Assumptions: Single-directory, PREFIX=/usr/local, standard targets (all/build/test/clean/install/help), no cross-compilation.

Stage 2: Documentation Lookup

When REQUIRED (MUST perform lookup):

• User requests integration with unfamiliar tools, frameworks, or build systems
• Complex build patterns not covered in Stage 3 examples (e.g., Bazel, Meson, custom toolchains)
• Docker/container integration (Dockerfile builds, multi-stage, registry push)
• CI/CD platform-specific integration (GitHub Actions, GitLab CI, Jenkins)
• Cross-compilation for unusual targets or embedded systems
• Package manager integration (Conan, vcpkg, Homebrew formulas)
• Multi-binary or multi-library projects
• Version embedding via ldflags or build-time variables

When OPTIONAL (may skip external lookup):

• Standard language patterns already covered in Stage 3 (C/C++, Go, Python, Java)
• Simple single-binary projects with no external dependencies
• User provides complete requirements with no ambiguity
• Internal docs already cover the required pattern comprehensively

Lookup Process (follow in order):

1. ALWAYS consult internal references/ FIRST using the Read tool (primary source of truth):

   Requirement	Read This Doc
   Docker/container targets	references/patterns-guide.md (Pattern 8: Docker Integration)
   Multi-binary projects	references/patterns-guide.md (Pattern 7: Multi-Binary Project)
   Go projects with version embedding	references/patterns-guide.md (Pattern 5: Go Project)
   Parallel builds, caching, ccache	references/optimization-guide.md
   Credentials, secrets, API keys	references/security-guide.md
   Complex dependencies, pattern rules	references/patterns-guide.md
   Order-only prerequisites	references/optimization-guide.md or references/targets-guide.md
   Variables, assignment operators	references/variables-guide.md

   CRITICAL: You MUST explicitly use the Read tool to consult relevant docs during generation, even if you have prior knowledge. Do NOT rely on context from earlier in the conversation. This ensures patterns are always current and correctly applied.

   Required Workflow Example (Docker + Go with version embedding):

   # Step 1: Use Read tool to get Go pattern
   Read: references/patterns-guide.md (find Pattern 5: Go Project)
   
   # Step 2: Use Read tool to get Docker pattern
   Read: references/patterns-guide.md (find Pattern 8: Docker Integration)
   
   # Step 3: Use Read tool for security considerations
   Read: references/security-guide.md (credential handling for docker-push)
   
   # Step 4: Generate Makefile combining patterns
   # Step 5: Document which docs were consulted in Makefile header

   Important: Internal docs contain vetted, production-ready patterns. Always read the relevant docs before external lookups.

2. Try context7 for external tool documentation (when internal docs don't cover a specific tool):

   # Only needed for tools/frameworks NOT covered in internal docs
   mcp__context7__resolve-library-id: "<tool-name>"
   mcp__context7__get-library-docs: topic="<integration-topic>"
   
   # Example topics:
   # - For Docker: topic="dockerfile best practices"
   # - For Go: topic="go build ldflags"
   # - For specific tools: topic="<tool> makefile integration"

   Note: Context7 may not have GNU Make-specific documentation. Skip if internal docs provide sufficient patterns.

3. Fallback to WebSearch (only if pattern not found in internal docs OR context7):

   "<specific-feature>" makefile best practices 2025
   Example: "docker makefile best practices 2025"
   Example: "go ldflags version makefile 2025"

   Trigger WebSearch when: Internal docs don't cover the specific integration AND context7 returns no relevant results.

Note: Document which internal docs you consulted in your response (add comment in generated Makefile header).

Stage 3: Generate Makefile

Header (choose one style)

Traditional (POSIX-compatible):

.DELETE_ON_ERROR:
.SUFFIXES:

Modern (GNU Make 4.0+, recommended):

SHELL := bash
.ONESHELL:
.SHELLFLAGS := -eu -o pipefail -c
.DELETE_ON_ERROR:
.SUFFIXES:
MAKEFLAGS += --warn-undefined-variables
MAKEFLAGS += --no-builtin-rules

Standard Variables

# User-overridable (use ?=)
CC ?= gcc
CFLAGS ?= -Wall -Wextra -O2
PREFIX ?= /usr/local
DESTDIR ?=

# GNU installation directories
BINDIR ?= $(PREFIX)/bin
LIBDIR ?= $(PREFIX)/lib
INCLUDEDIR ?= $(PREFIX)/include

# Project-specific (use :=)
PROJECT := myproject
VERSION := 1.0.0
SRCDIR := src
BUILDDIR := build
SOURCES := $(wildcard $(SRCDIR)/*.c)
OBJECTS := $(SOURCES:$(SRCDIR)/%.c=$(BUILDDIR)/%.o)

Language-Specific Build Rules

C/C++:

$(TARGET): $(OBJECTS)
	$(CC) $(LDFLAGS) $^ $(LDLIBS) -o $@

$(BUILDDIR)/%.o: $(SRCDIR)/%.c
	@mkdir -p $(@D)
	$(CC) $(CPPFLAGS) $(CFLAGS) -MMD -MP -c $< -o $@

-include $(OBJECTS:.o=.d)

Go:

$(TARGET): $(shell find . -name '*.go') go.mod
	go build -o $@ ./cmd/$(PROJECT)

Python:

.PHONY: build
build:
	python -m build

.PHONY: develop
develop:
	pip install -e .[dev]

Java:

$(BUILDDIR)/%.class: $(SRCDIR)/%.java
	@mkdir -p $(@D)
	javac -d $(BUILDDIR) -sourcepath $(SRCDIR) $<

Standard Targets

.PHONY: all clean install uninstall test help

## Build all targets
all: $(TARGET)

## Install to PREFIX
install: all
	install -d $(DESTDIR)$(BINDIR)
	install -m 755 $(TARGET) $(DESTDIR)$(BINDIR)/

## Remove built files
clean:
	$(RM) -r $(BUILDDIR) $(TARGET)

## Run tests
test:
	# Add test commands

## Show help
help:
	@echo "$(PROJECT) v$(VERSION)"
	@echo "Targets: all, install, clean, test, help"
	@echo "Override: make CC=clang PREFIX=/opt"

Stage 4: Validate and Format

CRITICAL: Always validate using devops-skills:makefile-validator skill.

1. Generate Makefile following stages above
2. Invoke devops-skills:makefile-validator skill
3. Fix any errors identified (MUST have 0 errors)
4. Apply formatting fixes (see "Formatting Step" below)
5. Fix warnings (SHOULD fix; explain if skipped)
6. Address info items for large/production projects
7. Re-validate until checks pass
8. Output structured validation report (REQUIRED - see format below)

Formatting Step (REQUIRED)

When mbake reports formatting issues, you MUST either:

1. Auto-apply formatting (preferred for minor issues):

   mbake format <Makefile>

2. Explain why not applied (if formatting would break functionality):

   Formatting not applied because:
   - [specific reason, e.g., "heredoc syntax would be corrupted"]
   - Manual review recommended for: [specific lines]

Formatting Decision Guide:

Validation Pass Criteria:

Known mbake False Positives (can be safely ignored):

The mbake validator may report warnings for valid GNU Make special targets. These are false positives and can be ignored:

Validation Report Output (REQUIRED)

After validation completes, you MUST output a structured report. Example format:

## Validation Report

**Result:** PASSED with warnings
**Errors:** 0
**Warnings:** 2
**Info:** 1

### Errors Fixed
- None

### Warnings Addressed
- Fixed: Added error handling to install target (|| exit 1)

### Warnings Skipped (with reasons)
- mbake reports ".DELETE_ON_ERROR" as unknown - this is a valid and critical
  GNU Make special target that ensures failed builds don't leave corrupt files.
  See: https://www.gnu.org/software/make/manual/html_node/Special-Targets.html

### Formatting Applied
- Yes - Applied `mbake format` to fix whitespace issues

### Info Items Addressed
- Added .NOTPARALLEL for Docker targets (parallel safety)
- Added error handling for docker-push target

### Remaining Issues
- None - Makefile is production-ready

Common Info Items to Address:

Production-Quality Requirements (MUST address for Docker/deploy targets):

When generating Makefiles with Docker or deployment targets, you MUST apply these production patterns:

1. Error Handling for docker-push:

   ## Push Docker image to registry (with error handling)
   docker-push: docker-build
   	@echo "Pushing $(IMAGE)..."
   	docker push $(IMAGE) || { echo "Failed to push $(IMAGE)"; exit 1; }
   	docker push $(IMAGE_LATEST) || { echo "Failed to push $(IMAGE_LATEST)"; exit 1; }

2. Parallel Safety for Docker targets:

   # Prevent parallel execution of Docker targets (race conditions)
   .NOTPARALLEL: docker-build docker-push docker-run

   Or use proper dependencies to serialize:

   docker-push: docker-build  # Ensures build completes before push
   docker-run: docker-build   # Ensures build completes before run

3. Install target error handling:

   install: $(TARGET)
   	install -d $(DESTDIR)$(PREFIX)/bin || exit 1
   	install -m 755 $(TARGET) $(DESTDIR)$(PREFIX)/bin/ || exit 1

Note: When validation shows info items about error handling or parallel safety, you MUST address them for any Makefile containing Docker, deploy, or install targets. Explain in your response which patterns were applied.

Validation Checklist:

• Syntax correct (make -n passes)
• All non-file targets have .PHONY
• Tab indentation (not spaces)
• No hardcoded credentials
• User-overridable variables use ?=
• .DELETE_ON_ERROR present
• MAKEFLAGS optimizations included (Modern header)
• Order-only prerequisites for build directories (large projects)
• Error handling in critical recipes (install, deploy, docker-push)

Best Practices

Variables

• ?= for user-overridable (CC, CFLAGS, PREFIX)
• := for project-specific (SOURCES, OBJECTS)
• Use pkg-config: CFLAGS += $(shell pkg-config --cflags lib)

Targets

• Always declare .PHONY for non-file targets
• Default target should be all
• Use .DELETE_ON_ERROR for safety
• Document with ## comments for help target

Directory Creation

Two approaches for creating build directories:

Simple (inline mkdir):

$(BUILDDIR)/%.o: $(SRCDIR)/%.c
	@mkdir -p $(@D)
	$(CC) $(CFLAGS) -c $< -o $@

Optimized (order-only prerequisites): Prevents unnecessary rebuilds when directory timestamps change.

$(BUILDDIR):
	@mkdir -p $@

$(BUILDDIR)/%.o: $(SRCDIR)/%.c | $(BUILDDIR)
	$(CC) $(CFLAGS) -c $< -o $@

Use order-only prerequisites (|) for large projects with many targets.

Recipes

• Use tabs, never spaces
• Quote variables in shell: $(RM) "$(TARGET)"
• Use @ prefix for quiet commands
• Test with make -n first

Helper Scripts (Optional)

These scripts are optional convenience tools for quick template generation.

When to Use Scripts vs Manual Generation

generate_makefile_template.sh

Generates a complete Makefile template for a specific project type.

bash scripts/generate_makefile_template.sh [TYPE] [NAME]

Types: c, c-lib, cpp, go, python, java, generic

Example:

bash scripts/generate_makefile_template.sh go myservice
# Creates Makefile with Go patterns, version embedding, standard targets

add_standard_targets.sh

Adds missing standard GNU targets to an existing Makefile.

bash scripts/add_standard_targets.sh [MAKEFILE] [TARGETS...]

Targets: all, install, uninstall, clean, distclean, test, check, help

Example:

bash scripts/add_standard_targets.sh Makefile install uninstall help
# Adds install, uninstall, help targets if they don't exist

Note: Manual generation following the Stage 3 patterns produces equivalent results but allows for more customization.

Documentation

Detailed guides in references/:

• makefile-structure.md - Organization, layout, includes
• variables-guide.md - Assignment operators, automatic variables
• targets-guide.md - Standard targets, .PHONY, prerequisites
• patterns-guide.md - Pattern rules, dependencies
• optimization-guide.md - Parallel builds, caching
• security-guide.md - Safe expansion, credential handling

Resources

• GNU Make Manual
• GNU Coding Standards
• Makefile Conventions