From 6a34c96eb0ec79244bd5f4ec59a4f8e2eb83c839 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Agn=C3=A8s=20Toulet?=
 <35176601+AgnesToulet@users.noreply.github.com>
Date: Tue, 7 Mar 2023 10:01:57 +0100
Subject: [PATCH] Start local schema registry

---
 kinds/gen.go                    |   1 +
 pkg/codegen/jenny_schema_reg.go |  44 ++++++++++
 scripts/kinds/schemaregistry.go | 150 ++++++++++++++++++++++++++++++++
 3 files changed, 195 insertions(+)
 create mode 100644 pkg/codegen/jenny_schema_reg.go
 create mode 100644 scripts/kinds/schemaregistry.go

diff --git a/kinds/gen.go b/kinds/gen.go
index a8dae5bb021..e93e92ffa50 100644
--- a/kinds/gen.go
+++ b/kinds/gen.go
@@ -46,6 +46,7 @@ func main() {
 		codegen.YamlCRDJenny(kindsys.GoCoreKindParentPath),
 		codegen.CRDKindRegistryJenny(filepath.Join("pkg", "registry", "corecrd")),
 		codegen.DocsJenny(filepath.Join("docs", "sources", "developers", "kinds", "core")),
+		codegen.SchemaRegistryJenny(filepath.Join("pkg", "kindsys", "schemaregistry")),
 	)
 
 	header := codegen.SlashHeaderMapper("kinds/gen.go")
diff --git a/pkg/codegen/jenny_schema_reg.go b/pkg/codegen/jenny_schema_reg.go
new file mode 100644
index 00000000000..d84ba0f0fb8
--- /dev/null
+++ b/pkg/codegen/jenny_schema_reg.go
@@ -0,0 +1,44 @@
+package codegen
+
+import (
+	"path/filepath"
+
+	"cuelang.org/go/cue"
+	"cuelang.org/go/cue/format"
+	"github.com/grafana/codejen"
+	"github.com/grafana/grafana/pkg/kindsys"
+)
+
+// SchemaRegistryJenny generates lineage files into the "next" folder
+// of the local schema registry.
+func SchemaRegistryJenny(path string) OneToOne {
+	return &schemaregjenny{
+		path: path,
+	}
+}
+
+type schemaregjenny struct {
+	path string
+}
+
+func (j *schemaregjenny) JennyName() string {
+	return "SchemaRegistryJenny"
+}
+
+func (j *schemaregjenny) Generate(kind kindsys.Kind) (*codejen.File, error) {
+	node := kind.Lineage().Underlying().Syntax(
+		cue.All(),
+		cue.Definitions(true),
+		cue.Docs(true),
+	)
+
+	bytes, err := format.Node(node)
+	if err != nil {
+		return nil, err
+	}
+
+	name := kind.Props().Common().MachineName
+	path := filepath.Join(j.path, "next", name+"_gen.cue")
+
+	return codejen.NewFile(path, bytes, j), nil
+}
diff --git a/scripts/kinds/schemaregistry.go b/scripts/kinds/schemaregistry.go
new file mode 100644
index 00000000000..6a1dd9b7f6b
--- /dev/null
+++ b/scripts/kinds/schemaregistry.go
@@ -0,0 +1,150 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strconv"
+
+	"github.com/grafana/thema"
+	"github.com/grafana/thema/load"
+)
+
+// TODO - change this
+const SchemaRegistryPath = "./pkg/kindsys/schemaregistry"
+
+func main() {
+	version, ok := os.LookupEnv("GRAFANA_VERSION")
+	if !ok {
+		panic(fmt.Errorf("GRAFANA_VERSION environment variable is missing"))
+	}
+
+	latestDir, err := findLatestDir(SchemaRegistryPath)
+	if err != nil {
+		panic(err)
+	}
+
+	nextSchemas, err := ioutil.ReadDir(SchemaRegistryPath + "/next")
+	if err != nil {
+		panic(err)
+	}
+
+	if latestDir == "" {
+		err = copySchemas(nextSchemas, filepath.Join(SchemaRegistryPath, version))
+		if err != nil {
+			panic(err)
+		}
+	}
+
+	for _, file := range nextSchemas {
+		// File is new - no need to compare with existing
+		if _, err := os.Stat(filepath.Join(SchemaRegistryPath, version, file.Name())); err != nil {
+			continue
+		}
+
+		bytes, err := os.ReadFile(filepath.Join(SchemaRegistryPath, version, file.Name()))
+		if err != nil {
+			panic(err)
+		}
+		oldLin, err := load.LineageFromBytes(bytes)
+		if err != nil {
+			panic(err)
+		}
+
+		bytes, err = os.ReadFile(filepath.Join(SchemaRegistryPath, "next", file.Name()))
+		if err != nil {
+			panic(err)
+		}
+		newLin, err := load.LineageFromBytes(bytes)
+		if err != nil {
+			panic(err)
+		}
+
+		isAppendOnly := thema.IsAppendOnly(oldLin, newLin)
+		fmt.Println(isAppendOnly)
+	}
+}
+
+func findLatestDir(path string) (string, error) {
+	re := regexp.MustCompile(`([0-9]+)\.([0-9]+)\.([0-9]+)`)
+	latestVersion := []uint64{0, 0, 0}
+	latestDir := ""
+
+	files, err := ioutil.ReadDir(path)
+	if err != nil {
+		return "", err
+	}
+
+	for _, file := range files {
+		if !file.IsDir() {
+			continue
+		}
+
+		parts := re.FindStringSubmatch(file.Name())
+		if parts == nil || len(parts) < 4 {
+			continue
+		}
+
+		version := make([]uint64, len(parts)-1)
+		for i := 1; i < len(parts); i++ {
+			version[i-1], _ = strconv.ParseUint(parts[i], 10, 32)
+		}
+
+		if isLess(latestVersion, version) {
+			latestVersion = version
+			latestDir = file.Name()
+		}
+	}
+
+	return latestDir, nil
+}
+
+func isLess(v1 []uint64, v2 []uint64) bool {
+	if len(v1) == 1 || len(v2) == 1 {
+		return v1[0] < v2[0]
+	}
+
+	return v1[0] < v2[0] || (v1[0] == v2[0] && isLess(v1[2:], v2[2:]))
+}
+
+func copySchemas(files []os.FileInfo, dest string) error {
+	_, err := os.Stat(dest)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return err
+		}
+
+		if err := os.Mkdir(dest, 0644); err != nil {
+			return err
+		}
+	}
+
+	for _, file := range files {
+		in, err := os.Open(filepath.Join(SchemaRegistryPath, "next", file.Name()))
+		if err != nil {
+			return err
+		}
+		defer in.Close()
+
+		out, err := os.Create(filepath.Join(dest, file.Name()))
+		if err != nil {
+			return err
+		}
+		defer func() {
+			cerr := out.Close()
+			if err == nil {
+				err = cerr
+			}
+		}()
+
+		if _, err = io.Copy(out, in); err != nil {
+			return err
+		}
+		err = out.Sync()
+	}
+
+	return nil
+}