Optimize spanner migration handler

.golangci.yml

@@ -28,3 +28,6 @@ issues:
   exclude:
     # gosec: Duplicated errcheck checks
     - G104
+    - bad syntax for struct tag pair
+    - struct literal uses unkeyed fields
+    - bad syntax for struct tag key

database/spanner/ddl/.got/snapshots/TestBasic/ddl-string.json

@@ -0,0 +1 @@
+"A B;\nA;\nA (B C);\nA \"B\";\nA <B , C>;\nA B , A (B (C D)) E\n"

database/spanner/ddl/.got/snapshots/TestBasic/ddl.json

@@ -0,0 +1,133 @@
+{
+  "Statements": [
+    {
+      "Expression": {
+        "Values": [
+          {
+            "Component": ["A", "B"],
+            "Braced": null,
+            "Bracketed": null
+          }
+        ]
+      },
+      "End": ";"
+    },
+    {
+      "Expression": {
+        "Values": [
+          {
+            "Component": ["A"],
+            "Braced": null,
+            "Bracketed": null
+          }
+        ]
+      },
+      "End": ";"
+    },
+    {
+      "Expression": {
+        "Values": [
+          {
+            "Component": ["A"],
+            "Braced": null,
+            "Bracketed": null
+          },
+          {
+            "Component": null,
+            "Braced": {
+              "Values": [
+                {
+                  "Component": ["B", "C"],
+                  "Braced": null,
+                  "Bracketed": null
+                }
+              ]
+            },
+            "Bracketed": null
+          }
+        ]
+      },
+      "End": ";"
+    },
+    {
+      "Expression": {
+        "Values": [
+          {
+            "Component": ["A", "\"B\""],
+            "Braced": null,
+            "Bracketed": null
+          }
+        ]
+      },
+      "End": ";"
+    },
+    {
+      "Expression": {
+        "Values": [
+          {
+            "Component": ["A"],
+            "Braced": null,
+            "Bracketed": null
+          },
+          {
+            "Component": null,
+            "Braced": null,
+            "Bracketed": {
+              "Values": [
+                {
+                  "Component": ["B", ",", "C"],
+                  "Braced": null,
+                  "Bracketed": null
+                }
+              ]
+            }
+          }
+        ]
+      },
+      "End": ";"
+    },
+    {
+      "Expression": {
+        "Values": [
+          {
+            "Component": ["A", "B", ",", "A"],
+            "Braced": null,
+            "Bracketed": null
+          },
+          {
+            "Component": null,
+            "Braced": {
+              "Values": [
+                {
+                  "Component": ["B"],
+                  "Braced": null,
+                  "Bracketed": null
+                },
+                {
+                  "Component": null,
+                  "Braced": {
+                    "Values": [
+                      {
+                        "Component": ["C", "D"],
+                        "Braced": null,
+                        "Bracketed": null
+                      }
+                    ]
+                  },
+                  "Bracketed": null
+                }
+              ]
+            },
+            "Bracketed": null
+          },
+          {
+            "Component": ["E"],
+            "Braced": null,
+            "Bracketed": null
+          }
+        ]
+      },
+      "End": ""
+    }
+  ]
+}

database/spanner/ddl/.got/snapshots/TestToMigrationStatements/list.json

@@ -0,0 +1,4 @@
+[
+  "CREATE TABLE test (id INT64)",
+  "CREATE PROPERTY GRAPH SocialGraph NODE TABLES (Person) EDGE TABLES (Knows)"
+]

database/spanner/ddl/ddl_test.go

@@ -0,0 +1,48 @@
+package ddl
+
+import (
+	"testing"
+
+	"github.com/ysmood/got"
+)
+
+func TestBasic(t *testing.T) {
+	g := got.T(t)
+
+	ddl, err := parser.ParseString("", `
+		-- Comment
+		A B;
+		A;
+		A (B C); /* 
+			Multi-line
+			comment
+		*/
+		A "B";
+		A <B, C>;
+		A -- Comment
+		B,
+		-- Comment
+		A (B (C D)) E
+	`)
+	g.E(err)
+
+	g.Snapshot("ddl", ddl)
+
+	g.Snapshot("ddl-string", ddl.String())
+}
+
+func TestToMigrationStatements(t *testing.T) {
+	g := got.T(t)
+
+	list, err := ToMigrationStatements("", `
+		-- Comment
+		CREATE TABLE test(id INT64);
+
+		CREATE PROPERTY GRAPH SocialGraph
+		NODE TABLES (Person)
+		EDGE TABLES (Knows);
+	`)
+	g.E(err)
+
+	g.Snapshot("list", list)
+}

database/spanner/ddl/format.go

@@ -0,0 +1,59 @@
+package ddl
+
+import (
+	"fmt"
+	"strings"
+)
+
+func ToMigrationStatements(path, ddl string) ([]string, error) {
+	parsed, err := parser.ParseString(path, ddl)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse DDL: %w", err)
+	}
+
+	list := []string{}
+
+	for _, statement := range parsed.Statements {
+		list = append(list, strings.TrimRight(statement.String(), ";"))
+	}
+
+	return list, nil
+}
+
+func (d *SpannerDDL) String() string {
+	out := ""
+
+	for _, s := range d.Statements {
+		out += s.String() + "\n"
+	}
+
+	return out
+}
+
+func (s *Statement) String() string {
+	return s.Expression.String() + s.End
+}
+
+func (e *Expression) String() string {
+	list := []string{}
+
+	for _, v := range e.Values {
+		list = append(list, v.String())
+	}
+
+	return strings.Join(list, " ")
+}
+
+func (v *Value) String() string {
+	out := ""
+
+	if v.Braced != nil {
+		out += "(" + v.Braced.String() + ")"
+	} else if v.Bracketed != nil {
+		out += "<" + v.Bracketed.String() + ">"
+	} else {
+		out += strings.Join(v.Component, " ")
+	}
+
+	return out
+}

database/spanner/ddl/parser.go

@@ -0,0 +1,46 @@
+package ddl
+
+import (
+	"github.com/alecthomas/participle/v2"
+	"github.com/alecthomas/participle/v2/lexer"
+)
+
+// SpannerDDL only parses the components that are relevant for the migration tool.
+// Main objectives:
+//   - Remove comments: spanner does allow comments in DDL.
+//   - Split DDL into statements: spanner requires the migration request to be a list of statements, not a single DDL file.
+//     Also each request should not exceed 10 statements.
+type SpannerDDL struct {
+	Statements []*Statement `@@*`
+}
+
+type Statement struct {
+	Expression *Expression `@@`
+	End        string      `@";"?`
+}
+
+type Expression struct {
+	Values []*Value `@@+`
+}
+
+type Value struct {
+	Component []string    `  @(Ident | String | Comma)+`
+	Braced    *Expression `| "(" @@ ")"`
+	Bracketed *Expression `| "<" @@ ">"`
+}
+
+var parser = participle.MustBuild[SpannerDDL](
+	participle.Lexer(lexer.MustSimple([]lexer.SimpleRule{
+		{"SingleLineComment", `--[^\n]*`},
+		{"MultiLineComment", `(?s)/\*.*?\*/`},
+		{"Whitespace", `\s+`},
+
+		{"StatementEnd", `;`},
+		{"Group", `[()<>]`},
+
+		{"Ident", `[a-zA-Z\d_]+`},
+		{"String", `"(?:\\.|[^"])*"`},
+		{"Comma", `,`},
+	})),
+	participle.Elide("SingleLineComment", "MultiLineComment", "Whitespace"),
+)