deploytool: Add README.md, migrate docs to it.

deploytool/cmd/build.go

-// Copyright 2016 The LUCI Authors. All rights reserved.
-// Use of this source code is governed under the Apache License, Version 2.0
-// that can be found in the LICENSE file.
-
-package main
-
-import (
-        "fmt"
-        "strings"
-
-        "github.com/luci/luci-go/common/errors"
-        "github.com/luci/luci-go/deploytool/api/deploy"
-        "github.com/luci/luci-go/deploytool/managedfs"
-)
-
-func flattenVarToDir(v string) string {
-        return strings.Map(func(r rune) rune {
-                switch {
-                case (r >= 'a' && r <= 'z'),
-                        (r >= 'A' && r <= 'Z'),
-                        (r >= '0' && r <= '9'),
-                        (r == '.'), (r == '_'):
-                        return r
-
-                default:
-                        return '_'
-                }
-        }, v)
-}
-
-// buildComponent runs the varuous build scripts defined by the specified
-// deployment component.
-//
-// After running the build scripts, variable substitution will occur on "c"
-// to update its directory.
-func buildComponent(w *work, c *layoutDeploymentComponent, root *managedfs.Dir) error {
-        if src := c.source(); !src.Source.RunScripts {
-                return errors.Reason("refusing to run scripts (run_scripts is false for %(source)q)").
-                        D("source", src.title).Err()
-        }
-
-        // Create our build directories and map them to variables.
-        c.buildDirs = make(map[string]string, len(c.Build))
-        dirs := make([]*managedfs.Dir, len(c.Build))
-        for i, b := range c.Build {
-                if _, has := c.buildDirs[b.DirKey]; has {
-                        return errors.Reason("duplicate build key [%(key)s]").D("key", b.DirKey).Err()
-                }
-
-                dir, err := root.EnsureDirectory(fmt.Sprintf("%d_%s", i, flattenVarToDir(b.DirKey)))
-                if err != nil {
-                        return errors.Annotate(err).Reason("failed to create build directory").Err()
-                }
-
-                dirs[i] = dir
-                c.buildDirs[b.DirKey] = dir.String()
-        }
-
-        // Apply build directories.
-        if err := c.expandPaths(); err != nil {
-                return errors.Annotate(err).Reason("failed to expand component paths").Err()
-        }
-
-        // Run all of our build scripts in parallel.
-        err := w.RunMulti(func(workC chan<- func() error) {
-                for i, b := range c.Build {
-                        i, b := i, b
-                        workC <- func() error {
-                                return runComponentBuild(w, c, b, dirs[i])
-                        }
-                }
-        })
-        if err != nil {
-                return errors.Annotate(err).Reason("failed to run component builds").Err()
-        }
-        return nil
-}
-
-func runComponentBuild(w *work, c *layoutDeploymentComponent, b *deploy.Component_Build, root *managedfs.Dir) error {
-        switch t := b.Operation.(type) {
-        case *deploy.Component_Build_PythonScript_:
-                ps := t.PythonScript
-
-                python, err := w.python()
-                if err != nil {
-                        return err
-                }
-
-                src := c.source()
-                scriptPath := src.pathTo(ps.Path, c.comp.Path)
-                buildDir := root.String()
-
-                args := append(make([]string, 0, 2+len(ps.ExtraArgs)),
-                        src.checkoutPath(),
-                        buildDir)
-                args = append(args, ps.ExtraArgs...)
-
-                if err := python.exec(scriptPath, args...).cwd(buildDir).check(w); err != nil {
-                        return errors.Annotate(err).Reason("failed to execute [%(scriptPath)s]").D("scriptPath", scriptPath).Err()
-                }
-                return nil
-
-        default:
-                return errors.Reason("unknown build type %(type)T").D("type", t).Err()
-        }
-}