Load functions for PostgreSQL extensions (#640)

* tools: Generate schemas for extensions

* postgresql: Add generated code

* sql/catalog: Implement extension loading

Add endtoend tests for common PostgreSQL extensions

Author: kyleconroy

internal/endtoend/testdata/pg_extensions/go/db.go

@@ -0,0 +1,4 @@
+CREATE EXTENSION IF NOT EXISTS "pg_trgm";
+
+-- name: WordSimilarity :one
+SELECT word_similarity('word', 'two words');

internal/endtoend/testdata/pg_extensions/go/models.go

@@ -0,0 +1,5 @@
+CREATE EXTENSION IF NOT EXISTS "pgcrypto";
+
+-- name: EncodeDigest :one
+SELECT encode(digest($1, 'sha1'), 'hex');
+

internal/endtoend/testdata/pg_extensions/go/pg_trgm.sql.go

@@ -0,0 +1,4 @@
+CREATE EXTENSION IF NOT EXISTS "uuid-ossp";
+
+-- name: GenerateUUID :one
+SELECT uuid_generate_v4();

internal/endtoend/testdata/pg_extensions/go/pgcrypto.sql.go

@@ -0,0 +1,12 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "engine": "postgresql",
+      "path": "go",
+      "name": "querytest",
+      "schema": "sql",
+      "queries": "sql"
+    }
+  ]
+}

internal/endtoend/testdata/pg_extensions/go/uuid_ossp.sql.go

@@ -7,6 +7,7 @@ func NewCatalog() *catalog.Catalog {
 	c.Schemas = append(c.Schemas, pgTemp())
 	c.Schemas = append(c.Schemas, genPGCatalog())
 	c.SearchPath = []string{"pg_catalog"}
+	c.LoadExtension = loadExtension
 	return c
 }
 
@@ -15,5 +16,20 @@ func NewCatalog() *catalog.Catalog {
 func newTestCatalog() *catalog.Catalog {
 	c := catalog.New("public")
 	c.Schemas = append(c.Schemas, pgTemp())
+	c.LoadExtension = loadExtension
 	return c
 }
+
+func loadExtension(name string) *catalog.Schema {
+	switch name {
+	case "citext":
+		return genCIText()
+	case "pg_trgm":
+		return genPGTrigram()
+	case "pgcrypto":
+		return genPGCrypto()
+	case "uuid-ossp":
+		return genUUIDOSSP()
+	}
+	return nil
+}