Add version to configuration file (#116)

* Add required version number to configuration file

`sqlc generate` now errors in the following cases:
- The required version number is empty or not equal to "1"
- There are zero packages configured
- An unknown key exists in the configuration file

Author: kyleconroy

README.md

@@ -269,6 +269,7 @@ in the directory where the `sqlc` command is run.
 
 ```json
 {
+  "version": "1",
   "packages": [
     {
       "name": "db",

internal/cmd/cmd.go

@@ -1,6 +1,7 @@
 package cmd
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -74,14 +75,29 @@ var initCmd = &cobra.Command{
 		if _, err := os.Stat("sqlc.json"); !os.IsNotExist(err) {
 			return nil
 		}
-		blob, err := json.MarshalIndent(dinosql.GenerateSettings{}, "  ", "")
+		blob, err := json.MarshalIndent(dinosql.GenerateSettings{Version: "1"}, "", "  ")
 		if err != nil {
 			return err
 		}
 		return ioutil.WriteFile("sqlc.json", blob, 0644)
 	},
 }
 
+const errMessageNoVersion = `The configuration file must have a version number.
+Set the version to 1 at the top of sqlc.json:
+
+{
+  "version": "1"
+  ...
+}
+`
+
+const errMessageUnknownVersion = `The configuration file has an invalid version number.
+The only supported version is "1".
+`
+
+const errMessageNoPackages = `No packages are configured`
+
 var genCmd = &cobra.Command{
 	Use:   "generate",
 	Short: "Generate Go code from SQL",
@@ -92,19 +108,17 @@ var genCmd = &cobra.Command{
 			os.Exit(1)
 		}
 
-		var settings dinosql.GenerateSettings
-		if err := json.Unmarshal(blob, &settings); err != nil {
-			switch err.(type) {
-			// TODO: Provide better error messages for sqlc.json parsing
-			// case *json.SyntaxError:
-			// case *json.InvalidUnmarshalError:
-			// case *json.UnmarshalFieldError:
-			// case *json.UnmarshalTypeError:
-			// case *json.UnsupportedTypeError:
-			// case *json.UnsupportedValueError:
-			default:
-				fmt.Fprintf(os.Stderr, "error parsing sqlc.json: %s\n", err)
+		settings, err := dinosql.ParseConfig(bytes.NewReader(blob))
+		if err != nil {
+			switch err {
+			case dinosql.ErrMissingVersion:
+				fmt.Fprintf(os.Stderr, errMessageNoVersion)
+			case dinosql.ErrUnknownVersion:
+				fmt.Fprintf(os.Stderr, errMessageUnknownVersion)
+			case dinosql.ErrNoPackages:
+				fmt.Fprintf(os.Stderr, errMessageNoPackages)
 			}
+			fmt.Fprintf(os.Stderr, "error parsing sqlc.json: %s\n", err)
 			os.Exit(1)
 		}
 

internal/dinosql/config.go

@@ -0,0 +1,46 @@
+package dinosql
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+)
+
+type PackageSettings struct {
+	Name                string `json:"name"`
+	Path                string `json:"path"`
+	Schema              string `json:"schema"`
+	Queries             string `json:"queries"`
+	EmitPreparedQueries bool   `json:"emit_prepared_queries"`
+	EmitJSONTags        bool   `json:"emit_json_tags"`
+}
+
+type GenerateSettings struct {
+	Version   string            `json:"version"`
+	Packages  []PackageSettings `json:"packages"`
+	Overrides []TypeOverride    `json:"overrides,omitempty"`
+	Rename    map[string]string `json:"rename,omitempty"`
+}
+
+var ErrMissingVersion = errors.New("no version number")
+var ErrUnknownVersion = errors.New("invalid version number")
+var ErrNoPackages = errors.New("no packages")
+
+func ParseConfig(rd io.Reader) (GenerateSettings, error) {
+	dec := json.NewDecoder(rd)
+	dec.DisallowUnknownFields()
+	var config GenerateSettings
+	if err := dec.Decode(&config); err != nil {
+		return config, err
+	}
+	if config.Version == "" {
+		return config, ErrMissingVersion
+	}
+	if config.Version != "1" {
+		return config, ErrUnknownVersion
+	}
+	if len(config.Packages) == 0 {
+		return config, ErrNoPackages
+	}
+	return config, nil
+}

internal/dinosql/config_test.go

@@ -0,0 +1,63 @@
+package dinosql
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+const missingVersion = `{
+}`
+
+const missingPackages = `{
+  "version": "1"
+}`
+
+const unknownVersion = `{
+  "version": "foo"
+}`
+
+const unknownFields = `{
+  "foo": "bar"
+}`
+
+func TestBadConfigs(t *testing.T) {
+	for _, test := range []struct {
+		name string
+		err  string
+		json string
+	}{
+		{
+			"missing version",
+			"no version number",
+			missingVersion,
+		},
+		{
+			"missing packages",
+			"no packages",
+			missingPackages,
+		},
+		{
+			"unknown version",
+			"invalid version number",
+			unknownVersion,
+		},
+		{
+			"unknown fields",
+			"json: unknown field \"foo\"",
+			unknownFields,
+		},
+	} {
+		tt := test
+		t.Run(tt.name, func(t *testing.T) {
+			_, err := ParseConfig(strings.NewReader(tt.json))
+			if err == nil {
+				t.Fatalf("expected err; got nil")
+			}
+			if diff := cmp.Diff(err.Error(), tt.err); diff != "" {
+				t.Errorf("differed (-want +got):\n%s", diff)
+			}
+		})
+	}
+}

internal/dinosql/parser.go

@@ -997,18 +997,3 @@ type TypeOverride struct {
 	GoType       string `json:"go_type"`
 	Null         bool   `json:"null"`
 }
-
-type PackageSettings struct {
-	Name                string `json:"name"`
-	Path                string `json:"path"`
-	Schema              string `json:"schema"`
-	Queries             string `json:"queries"`
-	EmitPreparedQueries bool   `json:"emit_prepared_queries"`
-	EmitJSONTags        bool   `json:"emit_json_tags"`
-}
-
-type GenerateSettings struct {
-	Packages  []PackageSettings `json:"packages"`
-	Overrides []TypeOverride    `json:"overrides"`
-	Rename    map[string]string `json:"rename"`
-}

internal/dinosql/testdata/ondeck/sqlc.json

@@ -1,4 +1,5 @@
 {
+  "version": "1",
   "packages": [
     {
       "name": "ondeck",