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Version: 0.1.0-alpha.2

Tool Dependencies

Tool dependencies verify that required binaries are available in PATH before your command runs.

Basic Usage​

depends_on: {
    tools: [
        {alternatives: ["go"]}
    ]
}

If go isn't found in PATH, the command fails with a clear error:

$ invowk cmd build

✗ Dependencies not satisfied

Command 'build' has unmet dependencies:

Missing Tools:
  • go - not found in PATH

Install the missing tools and try again.

Alternatives (OR Semantics)​

Specify multiple alternatives when any tool will work:

depends_on: {
    tools: [
        {alternatives: ["docker", "podman"]},
        {alternatives: ["node", "nodejs"]}
    ]
}

Invowk™ checks alternatives in order and stops at the first match. This is useful for:

  • Tools with compatible alternatives (docker/podman)
  • Editor preferences (nvim/vim/vi)
  • Version variants (python3/python)

Multiple Tool Requirements​

Each entry in tools is an AND requirement:

depends_on: {
    tools: [
        // Need (podman OR docker) AND kubectl AND helm
        {alternatives: ["podman", "docker"]},
        {alternatives: ["kubectl"]},
        {alternatives: ["helm"]},
    ]
}

All three must be satisfied (though alternatives within each are OR).

Real-World Examples​

Go Project​

{
    name: "build"
    depends_on: {
        tools: [
            {alternatives: ["go"]},
            {alternatives: ["git"]},  // For version info
        ]
    }
    implementations: [{
        script: """
            VERSION=$(git describe --tags --always)
            go build -ldflags="-X main.version=$VERSION" ./...
            """
        runtimes: [{name: "native"}]
    }]
}

Node.js Project​

{
    name: "build"
    depends_on: {
        tools: [
            // Prefer pnpm, but npm works too
            {alternatives: ["pnpm", "npm", "yarn"]},
            {alternatives: ["node"]},
        ]
    }
    implementations: [{
        script: "pnpm run build || npm run build"
        runtimes: [{name: "native"}]
    }]
}

Kubernetes Deployment​

{
    name: "deploy"
    depends_on: {
        tools: [
            {alternatives: ["kubectl"]},
            {alternatives: ["helm"]},
            {alternatives: ["podman", "docker"]},
        ]
    }
    implementations: [{
        script: """
            helm upgrade --install myapp ./charts/myapp
            kubectl rollout status deployment/myapp
            """
        runtimes: [{name: "native"}]
    }]
}

Python Project​

{
    name: "run"
    depends_on: {
        tools: [
            // Python 3 with various possible names
            {alternatives: ["python3", "python"]},
            // Virtual environment tool
            {alternatives: ["poetry", "pipenv", "pip"]},
        ]
    }
    implementations: [{
        script: "poetry run python main.py"
        runtimes: [{name: "native"}]
    }]
}

Runtime-Aware Validation​

Tool checks are validated according to the runtime:

Native Runtime​

Tools are checked on the host system:

{
    name: "build"
    depends_on: {
        tools: [{alternatives: ["go"]}]  // Checked on host
    }
    implementations: [{
        script: "go build ./..."
        runtimes: [{name: "native"}]
    }]
}

Virtual Runtime​

Tools are checked in the virtual shell environment:

{
    name: "build"
    depends_on: {
        tools: [{alternatives: ["go"]}]  // Checked in virtual shell
    }
    implementations: [{
        script: "go build ./..."
        runtimes: [{name: "virtual"}]
    }]
}

Container Runtime​

Tools are checked inside the container:

{
    name: "build"
    implementations: [{
        script: "go build ./..."
        runtimes: [{name: "container", image: "golang:1.21"}]
        depends_on: {
            // This checks for 'go' INSIDE the container
            tools: [{alternatives: ["go"]}]
        }
    }]
}

This is especially useful because:

  • The host doesn't need Go installed
  • You're validating the actual execution environment
  • You catch missing tools in custom container images

Common Patterns​

Check Before External Call​

{
    name: "upload"
    depends_on: {
        tools: [{alternatives: ["aws", "aws-cli"]}]
    }
    implementations: [{
        script: "aws s3 sync ./dist s3://my-bucket"
        runtimes: [{name: "native"}]
    }]
}

Database Tools​

{
    name: "db migrate"
    depends_on: {
        tools: [
            {alternatives: ["psql", "pgcli"]},  // PostgreSQL client
            {alternatives: ["migrate", "goose", "flyway"]},  // Migration tool
        ]
    }
    implementations: [{
        script: "migrate -path ./migrations -database $DATABASE_URL up"
        runtimes: [{name: "native"}]
    }]
}

Cross-Platform​

{
    name: "open docs"
    depends_on: {
        tools: [
            // Platform-specific openers
            {alternatives: ["xdg-open", "open", "start"]},
        ]
    }
    implementations: [{
        script: "xdg-open http://localhost:3000/docs || open http://localhost:3000/docs"
        runtimes: [{name: "native"}]
    }]
}

Best Practices​

  1. Use alternatives for compatible tools: {alternatives: ["podman", "docker"]}
  2. Order alternatives by preference: First alternative is checked first
  3. Keep tool lists minimal: Only require what's actually used
  4. Consider runtime context: Container tools are checked inside containers

Next Steps​