feat: Pattern generation

Author: codingconcepts

Diff for: Makefile

@@ -33,6 +33,9 @@ data_match:
 data_each_match:
 	go run dg.go -c ./examples/each_match_test/config.yaml -o ./csvs/each_match -i import.sql
 
+data_pattern:
+	go run dg.go -c ./examples/pattern_test/config.yaml -o ./csvs/pattern_test -i import.sql
+
 data: data_many_to_many data_person data_range_test data_input_test data_unique_test data_const_test
 	echo "done"
 

Diff for: examples/pattern_test/config.yaml

@@ -0,0 +1,13 @@
+tables:
+  # Generate data for a person table using the pattern generator.
+  - name: person
+    count: 1000
+    columns:
+      - name: id
+        type: gen
+        processor:
+          value: ${uuid}
+      - name: mobile
+        type: gen
+        processor:
+          pattern: \d{3}-\d{3}-\d{4}

Diff for: go.mod

@@ -11,6 +11,7 @@ require (
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/lucasjones/reggen v0.0.0-20200904144131-37ba4fa293bb // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	golang.org/x/exp v0.0.0-20220303212507-bbda1eaf7a17 // indirect
 )

Diff for: go.sum

@@ -2,6 +2,8 @@ github.com/brianvoe/gofakeit/v6 v6.22.0 h1:BzOsDot1o3cufTfOk+fWKE9nFYojyDV+XHdCW
 github.com/brianvoe/gofakeit/v6 v6.22.0/go.mod h1:Ow6qC71xtwm79anlwKRlWZW6zVq9D2XHE4QSSMP/rU8=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/lucasjones/reggen v0.0.0-20200904144131-37ba4fa293bb h1:w1g9wNDIE/pHSTmAaUhv4TZQuPBS6GV3mMz5hkgziIU=
+github.com/lucasjones/reggen v0.0.0-20200904144131-37ba4fa293bb/go.mod h1:5ELEyG+X8f+meRWHuqUOewBOhvHkl7M76pdGEansxW4=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/samber/lo v1.38.1 h1:j2XEAqXKb09Am4ebOg31SpvzUTTs6EN3VfgeLUhPdXM=

Diff for: internal/pkg/generator/gen_generator.go

@@ -1,18 +1,23 @@
 package generator
 
 import (
+	"fmt"
 	"strings"
 
 	"github.com/codingconcepts/dg/internal/pkg/model"
 	"github.com/codingconcepts/dg/internal/pkg/random"
+	"github.com/lucasjones/reggen"
 	"github.com/samber/lo"
 )
 
 // GenGenerator provides additional context to a gen column.
 type GenGenerator struct {
 	Value          string `yaml:"value"`
+	Pattern        string `yaml:"pattern"`
 	NullPercentage int    `yaml:"null_percentage"`
 	Format         string `yaml:"format"`
+
+	patternGenerator *reggen.Generator
 }
 
 func (g GenGenerator) GetFormat() string {
@@ -21,27 +26,43 @@ func (g GenGenerator) GetFormat() string {
 
 // Generate random data for a given column.
 func (g GenGenerator) Generate(t model.Table, c model.Column, files map[string]model.CSVFile) error {
+	if g.Value == "" && g.Pattern == "" {
+		return fmt.Errorf("gen must have either 'value' or 'pattern'")
+	}
+
 	if t.Count == 0 {
 		t.Count = len(lo.MaxBy(files[t.Name].Lines, func(a, b []string) bool {
 			return len(a) > len(b)
 		}))
 	}
 
+	if g.Pattern != "" {
+		var err error
+		if g.patternGenerator, err = reggen.NewGenerator(g.Pattern); err != nil {
+			return fmt.Errorf("creating regex generator: %w", err)
+		}
+	}
+
 	var line []string
 	for i := 0; i < t.Count; i++ {
-		line = append(line, g.replacePlaceholders())
+		s := g.generate()
+		line = append(line, s)
 	}
 
 	AddTable(t, c.Name, line, files)
 	return nil
 }
 
-func (pg GenGenerator) replacePlaceholders() string {
+func (pg GenGenerator) generate() string {
 	r := random.Intn(100)
 	if r < pg.NullPercentage {
 		return ""
 	}
 
+	if pg.Pattern != "" {
+		return pg.patternGenerator.Generate(255)
+	}
+
 	s := pg.Value
 
 	// Look for quick single-replacements.

Diff for: internal/pkg/generator/gen_generator_test.go

@@ -1,12 +1,14 @@
 package generator
 
 import (
+	"regexp"
 	"strconv"
 	"strings"
 	"testing"
 	"time"
 
 	"github.com/codingconcepts/dg/internal/pkg/model"
+	"github.com/lucasjones/reggen"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -15,6 +17,7 @@ func TestGenerateGenColumn(t *testing.T) {
 	cases := []struct {
 		name         string
 		value        string
+		pattern      string
 		format       string
 		expShapeFunc func(val string) bool
 	}{
@@ -40,11 +43,19 @@ func TestGenerateGenColumn(t *testing.T) {
 			expShapeFunc: func(val string) bool {
 				_, err := strconv.Atoi(val)
 				if err != nil {
-					(panic(err))
+					t.Fatal(err)
 				}
 				return err == nil
 			},
 		},
+		{
+			name:    "pattern",
+			pattern: `[a-z]{3}-[A-Z]{3}-\d{3}`,
+			expShapeFunc: func(val string) bool {
+				re := regexp.MustCompile(`[a-z]{3}-[A-Z]{3}-\d{3}`)
+				return re.MatchString(val)
+			},
+		},
 	}
 
 	for _, c := range cases {
@@ -59,8 +70,9 @@ func TestGenerateGenColumn(t *testing.T) {
 			}
 
 			g := GenGenerator{
-				Value:  c.value,
-				Format: c.format,
+				Value:   c.value,
+				Pattern: c.pattern,
+				Format:  c.format,
 			}
 
 			files := map[string]model.CSVFile{}
@@ -70,3 +82,18 @@ func TestGenerateGenColumn(t *testing.T) {
 		})
 	}
 }
+
+func BenchmarkGeneratePattern(b *testing.B) {
+	pattern := `[a-z]{3}-[A-Z]{3}-\d{3}`
+	patternGenerator, err := reggen.NewGenerator(pattern)
+	assert.NoError(b, err)
+
+	g := GenGenerator{
+		Pattern:          pattern,
+		patternGenerator: patternGenerator,
+	}
+
+	for i := 0; i < b.N; i++ {
+		g.generate()
+	}
+}