Define code generation interface via Protocol Buffers (#1406)

* Define CodeGenRequest and CodeGenResponse via `proto/plugin/codegen.proto`
* Move pattern matching to another package

Makefile

@@ -21,6 +21,9 @@ sqlc-pg-gen:
 start:
 	docker-compose up -d
 
+fmt:
+	go fmt ./...
+
 psql:
 	PGPASSWORD=mysecretpassword psql --host=127.0.0.1 --port=5432 --username=postgres dinotest
 

internal/cmd/generate.go

@@ -19,6 +19,7 @@ import (
 	"github.com/kyleconroy/sqlc/internal/debug"
 	"github.com/kyleconroy/sqlc/internal/multierr"
 	"github.com/kyleconroy/sqlc/internal/opts"
+	"github.com/kyleconroy/sqlc/internal/plugin"
 )
 
 const errMessageNoVersion = `The configuration file must have a version number.
@@ -187,6 +188,7 @@ func Generate(ctx context.Context, e Env, dir, filename string, stderr io.Writer
 			region = trace.StartRegion(ctx, "codegen")
 		}
 		var files map[string]string
+		var resp *plugin.CodeGenResponse
 		var out string
 		switch {
 		case sql.Gen.Go != nil:
@@ -197,14 +199,21 @@ func Generate(ctx context.Context, e Env, dir, filename string, stderr io.Writer
 			files, err = kotlin.Generate(result, combo)
 		case sql.Gen.Python != nil:
 			out = combo.Python.Out
-			files, err = python.Generate(result, combo)
+			resp, err = python.Generate(codeGenRequest(result, combo))
 		default:
 			panic("missing language backend")
 		}
 		if region != nil {
 			region.End()
 		}
 
+		if resp != nil {
+			files = map[string]string{}
+			for _, file := range resp.Files {
+				files[file.Name] = string(file.Contents)
+			}
+		}
+
 		if err != nil {
 			fmt.Fprintf(stderr, "# package %s\n", name)
 			fmt.Fprintf(stderr, "error generating code: %s\n", err)

internal/cmd/shim.go

@@ -0,0 +1,217 @@
+package cmd
+
+import (
+	"strings"
+
+	"github.com/kyleconroy/sqlc/internal/compiler"
+	"github.com/kyleconroy/sqlc/internal/config"
+	"github.com/kyleconroy/sqlc/internal/plugin"
+	"github.com/kyleconroy/sqlc/internal/sql/catalog"
+)
+
+func pluginOverride(o config.Override) *plugin.Override {
+	var column string
+	var table plugin.Identifier
+
+	if o.Column != "" {
+		colParts := strings.Split(o.Column, ".")
+		switch len(colParts) {
+		case 2:
+			table.Schema = "public"
+			table.Name = colParts[0]
+			column = colParts[1]
+		case 3:
+			table.Schema = colParts[0]
+			table.Name = colParts[1]
+			column = colParts[2]
+		case 4:
+			table.Catalog = colParts[0]
+			table.Schema = colParts[1]
+			table.Name = colParts[2]
+			column = colParts[3]
+		}
+	}
+	return &plugin.Override{
+		CodeType:   "", // FIXME
+		DbType:     o.DBType,
+		Nullable:   o.Nullable,
+		Column:     o.Column,
+		ColumnName: column,
+		Table:      &table,
+		PythonType: pluginPythonType(o.PythonType),
+	}
+}
+
+func pluginSettings(cs config.CombinedSettings) *plugin.Settings {
+	var over []*plugin.Override
+	for _, o := range cs.Overrides {
+		over = append(over, pluginOverride(o))
+	}
+	return &plugin.Settings{
+		Version:   cs.Global.Version,
+		Engine:    string(cs.Package.Engine),
+		Schema:    []string(cs.Package.Schema),
+		Queries:   []string(cs.Package.Queries),
+		Overrides: over,
+		Rename:    cs.Rename,
+		Python:    pluginPythonCode(cs.Python),
+	}
+}
+
+func pluginPythonCode(s config.SQLPython) *plugin.PythonCode {
+	return &plugin.PythonCode{
+		Out:                 s.Out,
+		Package:             s.Package,
+		EmitExactTableNames: s.EmitExactTableNames,
+		EmitSyncQuerier:     s.EmitSyncQuerier,
+		EmitAsyncQuerier:    s.EmitAsyncQuerier,
+	}
+}
+
+func pluginPythonType(pt config.PythonType) *plugin.PythonType {
+	return &plugin.PythonType{
+		Module: pt.Module,
+		Name:   pt.Name,
+	}
+}
+
+func pluginCatalog(c *catalog.Catalog) *plugin.Catalog {
+	var schemas []*plugin.Schema
+	for _, s := range c.Schemas {
+		var enums []*plugin.Enum
+		for _, typ := range s.Types {
+			enum, ok := typ.(*catalog.Enum)
+			if !ok {
+				continue
+			}
+			enums = append(enums, &plugin.Enum{
+				Name:    enum.Name,
+				Comment: enum.Comment,
+				Vals:    enum.Vals,
+			})
+		}
+		var tables []*plugin.Table
+		for _, t := range s.Tables {
+			var columns []*plugin.Column
+			for _, c := range t.Columns {
+				l := -1
+				if c.Length != nil {
+					l = *c.Length
+				}
+				columns = append(columns, &plugin.Column{
+					Name: c.Name,
+					Type: &plugin.Identifier{
+						Catalog: c.Type.Catalog,
+						Schema:  c.Type.Schema,
+						Name:    c.Type.Name,
+					},
+					Comment: c.Comment,
+					NotNull: c.IsNotNull,
+					IsArray: c.IsArray,
+					Length:  int32(l),
+					Table: &plugin.Identifier{
+						Catalog: t.Rel.Catalog,
+						Schema:  t.Rel.Schema,
+						Name:    t.Rel.Name,
+					},
+				})
+			}
+			tables = append(tables, &plugin.Table{
+				Rel: &plugin.Identifier{
+					Catalog: t.Rel.Catalog,
+					Schema:  t.Rel.Schema,
+					Name:    t.Rel.Name,
+				},
+				Columns: columns,
+				Comment: t.Comment,
+			})
+		}
+		schemas = append(schemas, &plugin.Schema{
+			Comment: s.Comment,
+			Name:    s.Name,
+			Tables:  tables,
+			Enums:   enums,
+		})
+	}
+	return &plugin.Catalog{
+		Name:          c.Name,
+		DefaultSchema: c.DefaultSchema,
+		Comment:       c.Comment,
+		Schemas:       schemas,
+	}
+}
+
+func pluginQueries(r *compiler.Result) []*plugin.Query {
+	var out []*plugin.Query
+	for _, q := range r.Queries {
+		var params []*plugin.Parameter
+		var columns []*plugin.Column
+		for _, c := range q.Columns {
+			columns = append(columns, pluginQueryColumn(c))
+		}
+		for _, p := range q.Params {
+			params = append(params, pluginQueryParam(p))
+		}
+		out = append(out, &plugin.Query{
+			Name:     q.Name,
+			Cmd:      q.Cmd,
+			Text:     q.SQL,
+			Comments: q.Comments,
+			Columns:  columns,
+			Params:   params,
+			Filename: q.Filename,
+		})
+	}
+	return out
+}
+
+func pluginQueryColumn(c *compiler.Column) *plugin.Column {
+	l := -1
+	if c.Length != nil {
+		l = *c.Length
+	}
+	out := &plugin.Column{
+		Name:    c.Name,
+		Comment: c.Comment,
+		NotNull: c.NotNull,
+		IsArray: c.IsArray,
+		Length:  int32(l),
+	}
+
+	if c.Type != nil {
+		out.Type = &plugin.Identifier{
+			Catalog: c.Type.Catalog,
+			Schema:  c.Type.Schema,
+			Name:    c.Type.Name,
+		}
+	} else {
+		out.Type = &plugin.Identifier{
+			Name: c.DataType,
+		}
+	}
+
+	if c.Table != nil {
+		out.Table = &plugin.Identifier{
+			Catalog: c.Table.Catalog,
+			Schema:  c.Table.Schema,
+			Name:    c.Table.Name,
+		}
+	}
+
+	return out
+}
+
+func pluginQueryParam(p compiler.Parameter) *plugin.Parameter {
+	return &plugin.Parameter{
+		Number: int32(p.Number),
+		Column: pluginQueryColumn(p.Column),
+	}
+}
+
+func codeGenRequest(r *compiler.Result, settings config.CombinedSettings) *plugin.CodeGenRequest {
+	return &plugin.CodeGenRequest{
+		Settings: pluginSettings(settings),
+		Catalog:  pluginCatalog(r.Catalog),
+		Queries:  pluginQueries(r),
+	}
+}