Taskfile Smart Caching with Sources & Generates

Intermediatev1.0.0

Use Taskfile's sources and generates for intelligent task caching — skip tasks when inputs haven't changed, fingerprint-based detection, and status commands for custom cache logic.

Content

Overview

Taskfile can skip tasks when source files haven't changed since the last run. This makes builds incremental — only rebuild what's needed. Configure sources (inputs) and generates (outputs) for automatic detection, or use status for custom logic.

Why This Matters

-Faster builds — skip unchanged tasks
-Incremental CI — only re-lint changed files
-Smart dependencies — rebuild only when sources change
-No manual cache invalidation — Taskfile tracks fingerprints

How It Works

Step 1: File-Based Caching

yaml

tasks:
  build:
    desc: Build Go binary
    sources:
      - cmd/**/*.go
      - internal/**/*.go
      - go.mod
      - go.sum
    generates:
      - bin/myapp
    cmds:
      - go build -o bin/myapp ./cmd/myapp
    # Skips if no .go files or go.mod changed since last build

Step 2: Status-Based Caching

yaml

tasks:
  install-deps:
    desc: Install npm dependencies
    status:
      - test -d node_modules
      - test node_modules/.package-lock.json -nt package-lock.json
    cmds:
      - npm ci
    # Skips if node_modules exists and is newer than lockfile

  docker-build:
    desc: Build Docker image
    status:
      - docker image inspect myapp:{{.VERSION}} > /dev/null 2>&1
    cmds:
      - docker build -t myapp:{{.VERSION}} .
    # Skips if image already exists

Step 3: Combining Sources and Status

yaml

tasks:
  generate-proto:
    desc: Generate protobuf Go code
    sources:
      - proto/**/*.proto
    generates:
      - gen/**/*.pb.go
    cmds:
      - protoc --go_out=gen/ proto/**/*.proto
    # Skips if .proto files haven't changed AND .pb.go files exist

  lint:
    desc: Run linters
    sources:
      - "**/*.go"
      - .golangci.yml
    cmds:
      - golangci-lint run
    # Re-lints only when Go files or config change

Step 4: Force Run (Bypass Cache)

bash

# Force run a cached task
task build --force

# Run with verbose output (shows cache decisions)
task build --verbose

Caching Methods

Method	Use When
sources + generates	File transformation (compile, generate)
sources only	Validation tasks (lint, test)
status	Custom conditions (Docker image exists, deps installed)
--force	Bypass all caching

Best Practices

-Use sources for all build tasks — makes them incremental
-Use status for installation checks — skip if already installed
-Use glob patterns: **/*.go matches all Go files recursively
-Use --verbose to debug cache decisions
-Combine sources + status for complex cache logic

Common Mistakes

-Not using sources/generates (every run rebuilds from scratch)
-Too broad glob patterns (cache never hits)
-Too narrow glob patterns (misses changed files)
-Forgetting --force when debugging cache issues

FAQ

Discussion

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How It Works

Step 1: File-Based Caching

yaml

tasks:
  build:
    desc: Build Go binary
    sources:
      - cmd/**/*.go
      - internal/**/*.go
      - go.mod
      - go.sum
    generates:
      - bin/myapp
    cmds:
      - go build -o bin/myapp ./cmd/myapp
    # Skips if no .go files or go.mod changed since last build

Step 2: Status-Based Caching

yaml

tasks:
  install-deps:
    desc: Install npm dependencies
    status:
      - test -d node_modules
      - test node_modules/.package-lock.json -nt package-lock.json
    cmds:
      - npm ci
    # Skips if node_modules exists and is newer than lockfile

  docker-build:
    desc: Build Docker image
    status:
      - docker image inspect myapp:{{.VERSION}} > /dev/null 2>&1
    cmds:
      - docker build -t myapp:{{.VERSION}} .
    # Skips if image already exists

Step 3: Combining Sources and Status

yaml

tasks:
  generate-proto:
    desc: Generate protobuf Go code
    sources:
      - proto/**/*.proto
    generates:
      - gen/**/*.pb.go
    cmds:
      - protoc --go_out=gen/ proto/**/*.proto
    # Skips if .proto files haven't changed AND .pb.go files exist

  lint:
    desc: Run linters
    sources:
      - "**/*.go"
      - .golangci.yml
    cmds:
      - golangci-lint run
    # Re-lints only when Go files or config change

Step 4: Force Run (Bypass Cache)

bash

# Force run a cached task
task build --force

# Run with verbose output (shows cache decisions)
task build --verbose

Method

Use When

sources + generates

File transformation (compile, generate)

sources only

Validation tasks (lint, test)

status

Custom conditions (Docker image exists, deps installed)

--force

Bypass all caching