migrate database from Datastore (not psql)

This is following a pattern I saw here:

https://github.com/GoogleCloudPlatform/golang-samples/blob/master/getting-started/bookshelf/db_mysql.go

Keep the database setup statements as code, and allow the Datastore to
run through those statements itself. This means it can use the right
DATABASE_URL, and we can do it between tests if necessary.

Makefile

@@ -8,11 +8,7 @@ run_collectors:
 
 .PHONY: migrate
 migrate:
-	./migrations/migrate migrations/*.sql
-
-.PHONY: migrate_heroku
-migrate_heroku:
-	MIGRATE_HEROKU=1 ./migrations/migrate migrations/*.sql
+	go run cmd/migrate/migrate.go
 
 .PHONY: test
 test:

cmd/migrate/migrate.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"fmt"
+	"github.com/fluidkeys/api/datastore"
+)
+
+func main() {
+	fmt.Print("Running database migrations.\n")
+
+	err := datastore.Initialize(datastore.MustReadDatabaseUrl())
+	if err != nil {
+		panic(err)
+	}
+	err = datastore.Migrate()
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Print("Done.\n")
+}

datastore/datastore.go

@@ -13,20 +13,6 @@ import (
 
 var db *sql.DB
 
-func init() {
-	databaseUrl, present := os.LookupEnv("DATABASE_URL")
-
-	if !present {
-		panic("Missing DATABASE_URL, it should be e.g. " +
-			"postgres://vagrant:password@localhost:5432/vagrant")
-	}
-
-	err := Initialize(databaseUrl)
-	if err != nil {
-		panic(err)
-	}
-}
-
 // Initialize initialises a postgres database from the given databaseUrl
 func Initialize(databaseUrl string) error {
 	var err error
@@ -169,6 +155,36 @@ func DeleteSecret(secretUUID uuid.UUID, recipientFingerprint fpr.Fingerprint) (f
 	return true, nil // found and deleted
 }
 
+func MustReadDatabaseUrl() string {
+	databaseUrl, present := os.LookupEnv("DATABASE_URL")
+
+	if !present {
+		panic("Missing DATABASE_URL, it should be e.g. " +
+			"postgres://vagrant:password@localhost:5432/vagrant")
+	}
+	return databaseUrl
+}
+
+func Migrate() error {
+	tx, err := db.Begin()
+	if err != nil {
+		return err
+	}
+
+	for _, sql := range migrateDatabaseStatements {
+		_, err := tx.Exec(sql)
+		if err != nil {
+			return fmt.Errorf("error (rolling back everything): %v", err)
+		}
+	}
+
+	err = tx.Commit()
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
 func dbFormat(fingerprint fpr.Fingerprint) string {
 	return fmt.Sprintf("4:%s", fingerprint.Hex())
 }

datastore/schema.go

@@ -0,0 +1,34 @@
+package datastore
+
+var migrateDatabaseStatements = []string{
+	`CREATE TABLE IF NOT EXISTS keys (
+                id BIGSERIAL PRIMARY KEY,
+              
+                -- fingerprint is the uppercase hex version of the fingerprint,
+		-- prepended by the version number and a colon, e.g.
+                -- 4:A999B7498D1A8DC473E53C92309F635DAD1B5517
+                fingerprint VARCHAR UNIQUE NOT NULL,
+                armored_public_key TEXT NOT NULL
+         )`,
+
+	`CREATE TABLE IF NOT EXISTS email_key_link (
+                -- The email -> key mapping is many-to-one, e.g. an email will always resolve
+                -- to a single key, and multiple emails can point to the same key.
+                --
+                -- If the key is deleted, the email should be deleted too since it's not used
+                -- for anything but mapping to a key.
+                
+                id BIGSERIAL PRIMARY KEY,
+                email VARCHAR UNIQUE NOT NULL,
+    
+                key_id INT UNIQUE NOT NULL REFERENCES keys(id) ON DELETE CASCADE
+         )`,
+
+	`CREATE TABLE IF NOT EXISTS secrets (
+                id BIGSERIAL PRIMARY KEY,
+                uuid UUID UNIQUE NOT NULL,
+                created_at TIMESTAMP NOT NULL,
+                recipient_key_id INT NOT NULL REFERENCES keys(id) ON DELETE CASCADE,
+                armored_encrypted_secret TEXT NOT NULL
+    )`,
+}