lektor_webpack_support.py

import os

from lektor.pluginsystem import Plugin
from lektor.reporter import reporter
from lektor.utils import locate_executable
from lektor.utils import portable_popen


class WebpackSupportPlugin(Plugin):
    name = "Webpack Support Plugin"
    description = "Super simple Lektor plugin that runs a webpack watcher"

    def __init__(self, *args, **kwargs):
        Plugin.__init__(self, *args, **kwargs)
        self.webpack_process = None

    def is_enabled(self, extra_flags):
        return bool(extra_flags.get("webpack"))

    def run_webpack(self, watch=False):
        webpack_root = os.path.join(self.env.root_path, "webpack")
        args = [os.path.join(webpack_root, "node_modules", ".bin", "webpack")]
        if watch:
            args.append("--watch")
        return portable_popen(args, cwd=webpack_root)

    def install_node_dependencies(self):
        webpack_root = os.path.join(self.env.root_path, "webpack")

        # Use yarn over npm if it's availabe and there is a yarn lockfile
        has_yarn_lockfile = os.path.exists(os.path.join(webpack_root, "yarn.lock"))
        pkg_manager = "npm"
        if locate_executable("yarn") is not None and has_yarn_lockfile:
            pkg_manager = "yarn"

        reporter.report_generic("Running {} install".format(pkg_manager))
        portable_popen([pkg_manager, "install"], cwd=webpack_root).wait()

    def on_server_spawn(self, **extra):
        extra_flags = extra.get("extra_flags") or extra.get("build_flags") or {}
        if not self.is_enabled(extra_flags):
            return
        self.install_node_dependencies()
        reporter.report_generic("Spawning webpack watcher")
        self.webpack_process = self.run_webpack(watch=True)

    def on_server_stop(self, **extra):
        if self.webpack_process is not None:
            reporter.report_generic("Stopping webpack watcher")
            self.webpack_process.kill()

    def on_before_build_all(self, builder, **extra):
        extra_flags = getattr(
            builder, "extra_flags", getattr(builder, "build_flags", None)
        )
        if not self.is_enabled(extra_flags) or self.webpack_process is not None:
            return
        self.install_node_dependencies()
        reporter.report_generic("Starting webpack build")
        self.run_webpack().wait()
        reporter.report_generic("Webpack build finished")