feat: absolute imports (#63)

* feat: go-like import style

jb now creates a directory structure inside of vendor/ that is similar to how go
does (github.com/grafana/jsonnet-libs). This is reflected in the final import
paths, which means they will be go-like

* refactor(spec/deps): named regexs

* feat: make goImportStyle configurable

Defaults to off, can be enabled in `jsonnetfile.json`

* fix: integration test

* doc: license headers

* fix(deps): remove GO_IMPORT_STYLE

not an option anymore, will always do so and symlink

* feat: symlink to legacy location

* feat: allow to disable legacy links

* fix(test): legacyImports in integration tests

* fix(spec): test

* fix: respect legacyName aliases

It was possible to alias packages by changing `name` previously.

While names are now absolute (and computed), legacy links should still respect
old aliases to avoid breaking code.

* fix(test): integration

* fix(init): keep legacyImports enabled for now

* feat: rewrite imports

adds a command to automatically rewrite imports from legacy to absolute style

* fix(tool): rewrite confused by prefixing packages

When a package was a prefix of another one, it broke.
Fixed that by using a proper regular expression. Added a test to make sure it
works as expected

* Update cmd/jb/init.go

* fix: exclude local packages from legacy linking

They actually still use the old style, which is fine. LegacyLinking
messed them up, but from now on it just ignores symlinks that match a localPackage.

tool/rewrite/rewrite.go

@@ -0,0 +1,127 @@
+// Copyright 2018 jsonnet-bundler authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package rewrite provides a tool that automatically rewrites legacy imports to
+// absolute ones
+package rewrite
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	"github.com/jsonnet-bundler/jsonnet-bundler/spec/deps"
+)
+
+var expr = regexp.MustCompile(`(?mU)(import ["'])(.*)(\/.*["'])`)
+
+// Rewrite changes all imports in `dir` from legacy to absolute style
+// All files in `vendorDir` are ignored
+func Rewrite(dir, vendorDir string, packages map[string]deps.Dependency) error {
+	imports := make(map[string]string)
+	for _, p := range packages {
+		if p.LegacyName() == p.Name() {
+			continue
+		}
+
+		imports[p.LegacyName()] = p.Name()
+	}
+
+	vendorFi, err := os.Stat(filepath.Join(dir, vendorDir))
+	if err != nil {
+		return err
+	}
+
+	// list all Jsonnet files
+	files := []string{}
+	if err := filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		if os.SameFile(vendorFi, info) {
+			return filepath.SkipDir
+		}
+
+		if ext := filepath.Ext(path); ext == ".jsonnet" || ext == ".libsonnet" {
+			files = append(files, path)
+		}
+		return nil
+	}); err != nil {
+		return err
+	}
+
+	// change the imports
+	for _, s := range files {
+		if err := replaceFile(s, imports); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func wrap(s, q string) string {
+	return fmt.Sprintf(`import %s%s`, q, s)
+}
+
+func replaceFile(name string, imports map[string]string) error {
+	raw, err := ioutil.ReadFile(name)
+	if err != nil {
+		return err
+	}
+
+	out := replace(string(raw), imports)
+	return ioutil.WriteFile(name, out, 0644)
+}
+
+func replace(data string, imports map[string]string) []byte {
+	contents := strings.Split(string(data), "\n")
+
+	// try to fix imports line by line
+	buf := make([]string, 0, len(contents))
+	for _, line := range contents {
+		match := expr.FindStringSubmatch(line)
+		// no import in this line: push unmodified
+		if len(match) == 0 {
+			buf = append(buf, line)
+			continue
+		}
+
+		// the legacyName
+		matchedName := match[2]
+
+		replaced := false
+		for legacy, absolute := range imports {
+			// not this import
+			if matchedName != legacy {
+				continue
+			}
+
+			// fix the import
+			replaced = true
+			buf = append(buf, expr.ReplaceAllString(line, "${1}"+absolute+"${3}"))
+		}
+
+		// no matching known import found? push unmodified
+		if !replaced {
+			buf = append(buf, line)
+		}
+	}
+
+	return []byte(strings.Join(buf, "\n"))
+}

tool/rewrite/rewrite_test.go

@@ -0,0 +1,76 @@
+// Copyright 2018 jsonnet-bundler authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package rewrite
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/jsonnet-bundler/jsonnet-bundler/spec/deps"
+)
+
+const sample = `
+(import "k.libsonnet") + // not vendored
+(import "ksonnet/abc.jsonnet") + // prefix of next
+(import "ksonnet.beta.4/k.libsonnet") + // normal import
+(import "github.com/ksonnet/ksonnet/def.jsonnet") + // already absolute
+(import "prometheus/mixin/whatever/abc.libsonnet") + // nested
+(import "mylib/foo.libsonnet") + // not managed by jb
+// completely unrelated line:
+[ "nice" ]
+`
+
+const want = `
+(import "k.libsonnet") + // not vendored
+(import "github.com/ksonnet/ksonnet/abc.jsonnet") + // prefix of next
+(import "github.com/ksonnet/ksonnet-lib/ksonnet.beta.4/k.libsonnet") + // normal import
+(import "github.com/ksonnet/ksonnet/def.jsonnet") + // already absolute
+(import "github.com/prometheus/prometheus/mixin/whatever/abc.libsonnet") + // nested
+(import "mylib/foo.libsonnet") + // not managed by jb
+// completely unrelated line:
+[ "nice" ]
+`
+
+func TestRewrite(t *testing.T) {
+	dir, err := ioutil.TempDir("", "jbrewrite")
+	require.Nil(t, err)
+	defer os.RemoveAll(dir)
+
+	name := filepath.Join(dir, "test.jsonnet")
+	err = ioutil.WriteFile(name, []byte(sample), 0644)
+	require.Nil(t, err)
+
+	vendorDir := filepath.Join(dir, "vendor")
+	err = os.MkdirAll(vendorDir, os.ModePerm)
+	require.Nil(t, err)
+
+	err = Rewrite(dir, "vendor", locks)
+	require.Nil(t, err)
+
+	content, err := ioutil.ReadFile(name)
+	require.Nil(t, err)
+
+	assert.Equal(t, want, string(content))
+}
+
+var locks = map[string]deps.Dependency{
+	"ksonnet":        *deps.Parse("", "github.com/ksonnet/ksonnet"),
+	"ksonnet.beta.4": *deps.Parse("", "github.com/ksonnet/ksonnet-lib/ksonnet.beta.4"),
+	"prometheus":     *deps.Parse("", "github.com/prometheus/prometheus"),
+}