From 8fa594e3f0a1d82aec6462aafd7e58da051a130b Mon Sep 17 00:00:00 2001
From: Matthew Dillon <mrdillon@alaska.edu>
Date: Mon, 6 Oct 2014 17:09:41 -0800
Subject: [PATCH] =?UTF-8?q?DB=20Migrations=20Replacing=20modl=E2=80=99s=20?=
 =?UTF-8?q?built-in=20table=20creation=20and=20removal=20with=20manual=20m?=
 =?UTF-8?q?igrations.=20Thanks=20to=20@DavidHuie=20for=20gomigrate!?=
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---
 cmd/bactdb/bactdb.go                         |  6 ++--
 datastore/db.go                              | 32 ++++++++++++++------
 datastore/db_test.go                         |  5 +--
 datastore/migrations/00001_AddUsers_down.sql |  5 +++
 datastore/migrations/00001_AddUsers_up.sql   | 19 ++++++++++++
 datastore/users.go                           |  3 --
 6 files changed, 53 insertions(+), 17 deletions(-)
 create mode 100644 datastore/migrations/00001_AddUsers_down.sql
 create mode 100644 datastore/migrations/00001_AddUsers_up.sql

diff --git a/cmd/bactdb/bactdb.go b/cmd/bactdb/bactdb.go
index 2c563eb..63a228f 100644
--- a/cmd/bactdb/bactdb.go
+++ b/cmd/bactdb/bactdb.go
@@ -117,8 +117,10 @@ The options are:
 	}
 
 	datastore.Connect()
+	migrationsPath := "./datastore/migrations"
+
 	if *drop {
-		datastore.Drop()
+		datastore.Drop(migrationsPath)
 	}
-	datastore.Create()
+	datastore.Create(migrationsPath)
 }
diff --git a/datastore/db.go b/datastore/db.go
index b2f4b96..e2d1b4d 100644
--- a/datastore/db.go
+++ b/datastore/db.go
@@ -5,6 +5,7 @@ import (
 	"os"
 	"sync"
 
+	"github.com/DavidHuie/gomigrate"
 	"github.com/jmoiron/modl"
 	"github.com/jmoiron/sqlx"
 	_ "github.com/lib/pq"
@@ -37,21 +38,32 @@ func Connect() {
 var createSQL []string
 
 // Create the database schema. It calls log.Fatal if it encounters an error.
-func Create() {
-	if err := DB.CreateTablesIfNotExists(); err != nil {
-		log.Fatal("Error creating tables: ", err)
+func Create(path string) {
+	migrator, err := gomigrate.NewMigrator(DB.Dbx.DB, gomigrate.Postgres{}, path)
+	if err != nil {
+		log.Fatal("Error initializing migrations: ", err)
 	}
-	for _, query := range createSQL {
-		if _, err := DB.Exec(query); err != nil {
-			log.Fatalf("Error running query %q: %s", query, err)
-		}
+
+	pwd, err := os.Getwd()
+	log.Print("current path: ", pwd)
+
+	err = migrator.Migrate()
+	if err != nil {
+		log.Fatal("Error applying migrations: ", err)
 	}
 }
 
 // Drop the database schema
-func Drop() {
-	// TODO(mrd): raise errors.
-	DB.DropTables()
+func Drop(path string) {
+	migrator, err := gomigrate.NewMigrator(DB.Dbx.DB, gomigrate.Postgres{}, path)
+	if err != nil {
+		log.Fatal("Error initializing migrations: ", err)
+	}
+
+	err = migrator.RollbackAll()
+	if err != nil {
+		log.Fatal("Error rolling back migrations: ", err)
+	}
 }
 
 // transact calls fn in a DB transaction. If dbh is a transaction, then it just calls
diff --git a/datastore/db_test.go b/datastore/db_test.go
index c8103e0..e19317e 100644
--- a/datastore/db_test.go
+++ b/datastore/db_test.go
@@ -21,6 +21,7 @@ func init() {
 
 	// Reset DB
 	Connect()
-	Drop()
-	Create()
+	migrationsPath := "./migrations"
+	Drop(migrationsPath)
+	Create(migrationsPath)
 }
diff --git a/datastore/migrations/00001_AddUsers_down.sql b/datastore/migrations/00001_AddUsers_down.sql
new file mode 100644
index 0000000..5bc15a4
--- /dev/null
+++ b/datastore/migrations/00001_AddUsers_down.sql
@@ -0,0 +1,5 @@
+-- bactdb
+-- Matthew R Dillon
+
+DROP TABLE users;
+
diff --git a/datastore/migrations/00001_AddUsers_up.sql b/datastore/migrations/00001_AddUsers_up.sql
new file mode 100644
index 0000000..9dd8907
--- /dev/null
+++ b/datastore/migrations/00001_AddUsers_up.sql
@@ -0,0 +1,19 @@
+-- bactdb
+-- Matthew R Dillon
+
+CREATE TABLE users (
+    id BIGSERIAL NOT NULL,
+    username CHARACTER VARYING(100),
+
+    createdat TIMESTAMP WITH TIME ZONE,
+    updatedat TIMESTAMP WITH TIME ZONE,
+    deletedat TIMESTAMP WITH TIME ZONE,
+
+    CONSTRAINT users_pkey PRIMARY KEY (id)
+);
+
+CREATE UNIQUE INDEX username_idx
+    ON users
+    USING btree
+    (username COLLATE pg_catalog."default");
+
diff --git a/datastore/users.go b/datastore/users.go
index ee233a4..fdacc6c 100644
--- a/datastore/users.go
+++ b/datastore/users.go
@@ -12,9 +12,6 @@ import (
 
 func init() {
 	DB.AddTableWithName(models.User{}, "users").SetKeys(true, "Id")
-	createSQL = append(createSQL,
-		`CREATE UNIQUE INDEX username_idx ON users (username);`,
-	)
 }
 
 type usersStore struct {