Implement schemagen ignore-names flag

Co-authored by Alexander Setzer <Alexander.Setzer@alfatraining.de>

cmd/schemagen/schemagen.go

@@ -11,6 +11,7 @@ import (
 	"log"
 	"os"
 	"path"
+	"regexp"
 	"strings"
 
 	"github.com/gocql/gocql"
@@ -26,6 +27,7 @@ var (
 	flagOutput      = cmd.String("output", "models", "the name of the folder to output to")
 	flagUser        = cmd.String("user", "", "user for password authentication")
 	flagPassword    = cmd.String("password", "", "password for password authentication")
+	flagIgnoreNames = cmd.String("ignore-names", "", "a comma-separated list of table, view or index names to ignore")
 )
 
 var (
@@ -82,6 +84,24 @@ func renderTemplate(md *gocql.KeyspaceMetadata) ([]byte, error) {
 		log.Fatalln("unable to parse models template:", err)
 	}
 
+	ignoredNames := make(map[string]struct{})
+	for _, ignoredName := range strings.Split(*flagIgnoreNames, ",") {
+		ignoredNames[ignoredName] = struct{}{}
+	}
+	for name := range ignoredNames {
+		delete(md.Tables, name)
+	}
+
+	orphanedTypes := make(map[string]struct{})
+	for userTypeName := range md.UserTypes {
+		if !usedInTables(userTypeName, md.Tables) {
+			orphanedTypes[userTypeName] = struct{}{}
+		}
+	}
+	for typeName := range orphanedTypes {
+		delete(md.UserTypes, typeName)
+	}
+
 	imports := make([]string, 0)
 	for _, t := range md.Tables {
 		for _, c := range t.Columns {
@@ -135,3 +155,28 @@ func existsInSlice(s []string, v string) bool {
 
 	return false
 }
+
+// userTypes finds Cassandra schema types enclosed in angle brackets.
+// Calling FindAllStringSubmatch on it will return a slice of string slices containing two elements.
+// The second element contains the name of the type.
+//
+//	[["<my_type,", "my_type"] ["my_other_type>", "my_other_type"]]
+var userTypes = regexp.MustCompile(`(?:<|\s)(\w+)(?:>|,)`) // match all types contained in set<X>, list<X>, tuple<A, B> etc.
+
+// usedInTables reports whether the typeName is used in any of columns of the provided tables.
+func usedInTables(typeName string, tables map[string]*gocql.TableMetadata) bool {
+	for _, table := range tables {
+		for _, column := range table.Columns {
+			if typeName == column.Validator {
+				return true
+			}
+			matches := userTypes.FindAllStringSubmatch(column.Validator, -1)
+			for _, s := range matches {
+				if s[1] == typeName {
+					return true
+				}
+			}
+		}
+	}
+	return false
+}

cmd/schemagen/schemagen_test.go

@@ -5,8 +5,10 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"strings"
 	"testing"
 
+	"github.com/gocql/gocql"
 	"github.com/google/go-cmp/cmp"
 	"github.com/scylladb/gocqlx/v2/gocqlxtest"
 )
@@ -16,6 +18,13 @@ var flagUpdate = flag.Bool("update", false, "update golden file")
 func TestSchemagen(t *testing.T) {
 	flag.Parse()
 	createTestSchema(t)
+
+	// add ignored types and table
+	*flagIgnoreNames = strings.Join([]string{
+		"composers",
+		"composers_by_name",
+		"label",
+	}, ",")
 	b := runSchemagen(t, "foobar")
 
 	const goldenFile = "testdata/models.go.txt"
@@ -34,6 +43,76 @@ func TestSchemagen(t *testing.T) {
 	}
 }
 
+func Test_usedInTables(t *testing.T) {
+	tests := map[string]struct {
+		columnValidator string
+		typeName        string
+	}{
+		"matches given a frozen collection": {
+			columnValidator: "frozen<album>",
+			typeName:        "album",
+		},
+		"matches given a set": {
+			columnValidator: "set<artist>",
+			typeName:        "artist",
+		},
+		"matches given a list": {
+			columnValidator: "list<song>",
+			typeName:        "song",
+		},
+		"matches given a tuple: first of two elements": {
+			columnValidator: "tuple<first, second>",
+			typeName:        "first",
+		},
+		"matches given a tuple: second of two elements": {
+			columnValidator: "tuple<first, second>",
+			typeName:        "second",
+		},
+		"matches given a tuple: first of three elements": {
+			columnValidator: "tuple<first, second, third>",
+			typeName:        "first",
+		},
+		"matches given a tuple: second of three elements": {
+			columnValidator: "tuple<first, second, third>",
+			typeName:        "second",
+		},
+		"matches given a tuple: third of three elements": {
+			columnValidator: "tuple<first, second, third>",
+			typeName:        "third",
+		},
+		"matches given a frozen set": {
+			columnValidator: "set<frozen<album>>",
+			typeName:        "album",
+		},
+		"matches snake_case names given a nested map": {
+			columnValidator: "map<album, tuple<first, map<map_key, map-value>, third>>",
+			typeName:        "map_key",
+		},
+	}
+
+	for name, tt := range tests {
+		t.Run(name, func(t *testing.T) {
+			tables := map[string]*gocql.TableMetadata{
+				"table": {Columns: map[string]*gocql.ColumnMetadata{
+					"column": {Validator: tt.columnValidator},
+				}},
+			}
+			if !usedInTables(tt.typeName, tables) {
+				t.Fatal()
+			}
+		})
+	}
+
+	t.Run("doesn't panic with empty type name", func(t *testing.T) {
+		tables := map[string]*gocql.TableMetadata{
+			"table": {Columns: map[string]*gocql.ColumnMetadata{
+				"column": {Validator: "map<text, album>"},
+			}},
+		}
+		usedInTables("", tables)
+	})
+}
+
 func createTestSchema(t *testing.T) {
 	t.Helper()
 
@@ -73,6 +152,29 @@ func createTestSchema(t *testing.T) {
 	if err != nil {
 		t.Fatal("create table:", err)
 	}
+
+	err = session.ExecStmt(`CREATE TABLE IF NOT EXISTS schemagen.composers (
+		id uuid PRIMARY KEY,
+		name text)`)
+	if err != nil {
+		t.Fatal("create table:", err)
+	}
+
+	err = session.ExecStmt(`CREATE MATERIALIZED VIEW IF NOT EXISTS schemagen.composers_by_name AS
+    	SELECT id, name
+    	FROM composers
+    	WHERE id IS NOT NULL AND name IS NOT NULL
+    	PRIMARY KEY (id, name)`)
+	if err != nil {
+		t.Fatal("create view:", err)
+	}
+
+	err = session.ExecStmt(`CREATE TYPE IF NOT EXISTS schemagen.label (
+		name text,
+		artists set<text>)`)
+	if err != nil {
+		t.Fatal("create type:", err)
+	}
 }
 
 func runSchemagen(t *testing.T, pkgname string) []byte {