refactor: graph from directory

cobble.go

@@ -27,8 +27,8 @@ var up = &cobra.Command{
 		}
 
 		migrationRoot := args[0]
-		migrationHistory, err := getMigrations(migrationRoot)
+		migrationGraph, _ := NewMigrationGraphFromDirectory(migrationRoot)
-
+		migrationHistory, _ := migrationGraph.GetLinearHistory()
 		for _, migration := range migrationHistory {
 			log.Printf("%s", migration.Name)
 			if err = ApplyMigration(db, migration); err != nil {

migrate.go

@@ -11,7 +11,6 @@ import (
 
 	"log"
 	"os"
-	"path/filepath"
 )
 
 var commentPrefix = []byte("--")
@@ -79,42 +78,3 @@ func gatherMigrationHeaders(migrationFile *os.File) MigrationHeaders {
 
 	return MigrationHeaders{Requirements: requirements}
 }
-
-// Gathers available migrations from the migration root directory.
-//
-// Migrations are expected to be .sql files.
-func getMigrations(migrationsRoot string) ([]Migration, error) {
-	files, err := os.ReadDir(migrationsRoot)
-
-	if err != nil {
-		log.Printf("Failed to read migration directory: %s", migrationsRoot)
-		return []Migration{}, err
-	}
-
-	migrationGraph := NewMigrationGraph()
-
-	for _, file := range files {
-		filename := file.Name()
-
-		if filepath.Ext(filename) != ".sql" {
-			continue
-		}
-
-		migrationPath := filepath.Join(migrationsRoot, file.Name())
-
-		file, _ := os.Open(migrationPath)
-
-		headers := gatherMigrationHeaders(file)
-
-		requirements := ""
-
-		if len(headers.Requirements) > 0 {
-			requirements = headers.Requirements[0]
-		}
-
-		migration := NewMigration(migrationPath, filepath.Base(file.Name()), requirements)
-		migrationGraph.AddMigration(migration)
-	}
-
-	return migrationGraph.GetLinearHistory()
-}

migrate_test.go

@@ -39,7 +39,8 @@ func TestGetMigrationsGathersSqlFiles(t *testing.T) {
 	os.WriteFile(filepath.Join(root, "0002.sql"), []byte("--requires:0001.sql\nSELECT 1 from table;"), 0750)
 	os.WriteFile(filepath.Join(root, "0003.sql"), []byte("--requires:0002.sql\nSELECT 1 from table;"), 0750)
 
-	migrations, err := getMigrations(root)
+	migrationGraph, err := NewMigrationGraphFromDirectory(root)
+	migrations, _ := migrationGraph.GetLinearHistory()
 
 	if len(migrations) != 3 {
 		t.Errorf("Expected three migrations collected, got %d instead.", len(migrations))
@@ -71,7 +72,8 @@ func TestGetMigrationsIgnoresNonMigrationFiles(t *testing.T) {
 	os.WriteFile(filepath.Join(root, "0001.sql"), []byte("SELECT 1 from table;"), 0750)
 	os.WriteFile(filepath.Join(root, "0002.txt"), []byte("SELECT 1 from table;"), 0750)
 
-	migrations, err := getMigrations(root)
+	migrationGraph, err := NewMigrationGraphFromDirectory(root)
+	migrations, _ := migrationGraph.GetLinearHistory()
 
 	if len(migrations) != 1 {
 		t.Errorf("Expected one migration collected, got %d instead.", len(migrations))
@@ -95,7 +97,8 @@ func TestGetMigrationsIgnoresNonMigrationFiles(t *testing.T) {
 }
 
 func TestGetMigrationsReturnsErrorIfInvalidRootDirectory(t *testing.T) {
-	migrations, err := getMigrations("not-root")
+	migrationGraph, _ := NewMigrationGraphFromDirectory("not-root")
+	migrations, err := migrationGraph.GetLinearHistory()
 
 	if len(migrations) != 0 {
 		t.Errorf("Did not expect any migrations returned, got %#v", migrations)
@@ -111,8 +114,8 @@ func TestGetMigrationsParsesRequirementsInCommentHeaders(t *testing.T) {
 	os.WriteFile(filepath.Join(root, "0000.sql"), []byte("SELECT 1 from table;"), 0750)
 	os.WriteFile(filepath.Join(root, "0001.sql"), []byte("-- requires: 0000.sql\nSELECT 1 from table;"), 0750)
 
-	migrations, err := getMigrations(root)
+	migrationGraph, _ := NewMigrationGraphFromDirectory(root)
-
+	migrations, err := migrationGraph.GetLinearHistory()
 	if err != nil {
 		t.Errorf("Expected no error returned, got %#v", err)
 	}
@@ -136,8 +139,8 @@ func TestGetMigrationsIgnoresUnrecognizedCommentHeaders(t *testing.T) {
 	root := t.TempDir()
 	os.WriteFile(filepath.Join(root, "0001.sql"), []byte("-- randomheader\nSELECT 1 from table;"), 0750)
 
-	migrations, err := getMigrations(root)
+	migrationGraph, _ := NewMigrationGraphFromDirectory(root)
-
+	migrations, err := migrationGraph.GetLinearHistory()
 	if err != nil {
 		t.Errorf("Expected no error returned, got %#v", err)
 	}
@@ -163,9 +166,9 @@ func TestMigrateRunsSqlOnDBConnection(t *testing.T) {
 	migrationSql := "SELECT 1 FROM table;"
 	os.WriteFile(migrationPath, []byte(migrationSql), 0750)
 
-	migrations, _ := getMigrations(root)
+	migrationGraph, _ := NewMigrationGraphFromDirectory(root)
-
+	migrations, err := migrationGraph.GetLinearHistory()
-	err := ApplyMigration(mockDb, migrations[0])
+	err = ApplyMigration(mockDb, migrations[0])
 
 	if err != nil {
 		t.Errorf("Expected no error returned, got %#v", err)
@@ -197,9 +200,10 @@ func TestMigrateReturnsErrorOnFailToRunSQL(t *testing.T) {
 
 	migrationPath := filepath.Join(root, "0001.sql")
 	os.WriteFile(migrationPath, []byte(migrationSql), 0750)
+	migrationGraph, _ := NewMigrationGraphFromDirectory(root)
+	migrations, err := migrationGraph.GetLinearHistory()
 
-	migrations, _ := getMigrations(root)
+	err = ApplyMigration(mockDb, migrations[0])
-	err := ApplyMigration(mockDb, migrations[0])
 
 	if err == nil {
 		t.Errorf("Expected error returned, got nil")

migration_graph.go

@@ -3,6 +3,9 @@ package main
 import (
 	"errors"
 	"fmt"
+	"log"
+	"os"
+	"path/filepath"
 )
 
 type MigrationGraph struct {
@@ -18,6 +21,41 @@ func NewMigrationGraph() MigrationGraph {
 	return MigrationGraph{Migrations: map[string]Migration{}, parentage: map[string]*Migration{}}
 }
 
+func NewMigrationGraphFromDirectory(pathRoot string) (MigrationGraph, error) {
+	migrationGraph := NewMigrationGraph()
+
+	files, err := os.ReadDir(pathRoot)
+
+	if err != nil {
+		log.Printf("Failed to read migration directory: %s", pathRoot)
+		return migrationGraph, err
+	}
+	for _, file := range files {
+		filename := file.Name()
+
+		if filepath.Ext(filename) != ".sql" {
+			continue
+		}
+
+		migrationPath := filepath.Join(pathRoot, file.Name())
+
+		file, _ := os.Open(migrationPath)
+
+		headers := gatherMigrationHeaders(file)
+
+		requirements := ""
+
+		if len(headers.Requirements) > 0 {
+			requirements = headers.Requirements[0]
+		}
+
+		migration := NewMigration(migrationPath, filepath.Base(file.Name()), requirements)
+		migrationGraph.AddMigration(migration)
+	}
+
+	return migrationGraph, nil
+}
+
 // Adds a migration to the graph.
 //
 // This also adds the migration to the parentage mappings to link it