blubber/config/node.go

package config

import (
	"gerrit.wikimedia.org/r/blubber/build"
)

// NodeConfig holds configuration fields related to the Node environment and
// whether/how to install NPM packages.
//
type NodeConfig struct {
	Requirements []string `json:"requirements"`                     // install requirements from given files
	Env          string   `json:"env" validate:"omitempty,nodeenv"` // environment name ("production" install)
}

// Merge takes another NodeConfig and merges its fields into this one's,
// overwriting both the environment and requirements files.
//
func (nc *NodeConfig) Merge(nc2 NodeConfig) {
	if nc2.Requirements != nil {
		nc.Requirements = nc2.Requirements
	}

	if nc2.Env != "" {
		nc.Env = nc2.Env
	}
}

// InstructionsForPhase injects instructions into the build related to Node
// dependency installation and setting of the NODE_ENV.
//
// PhasePreInstall
//
// Installs Node package dependencies declared in requirements files into the
// application directory. Only production related packages are install if
// NodeConfig.Env is set to "production" in which case `npm dedupe` is also
// run. Installing dependencies during the build.PhasePreInstall phase allows
// a compiler implementation (e.g. Docker) to produce cache-efficient output
// so only changes to package.json will invalidate these steps of the image
// build.
//
// PhasePostInstall
//
// Injects build.Env instructions for NODE_ENV, setting the environment
// according to the configuration.
//
func (nc NodeConfig) InstructionsForPhase(phase build.Phase) []build.Instruction {
	switch phase {
	case build.PhasePreInstall:
		if len(nc.Requirements) > 0 {
			npmInstall := build.RunAll{[]build.Run{
				{"npm install", []string{}},
			}}

			if nc.Env == "production" {
				npmInstall.Runs[0].Arguments = []string{"--production"}
				npmInstall.Runs = append(npmInstall.Runs,
					build.Run{"npm dedupe", []string{}},
				)
			}

			return append(
				build.SyncFiles(nc.Requirements, "."),
				npmInstall,
			)
		}
	case build.PhasePostInstall:
		if nc.Env != "" || len(nc.Requirements) > 0 {
			return []build.Instruction{build.Env{map[string]string{
				"NODE_ENV": nc.Env,
			}}}
		}
	}

	return []build.Instruction{}
}