chore(examples): add example simple migration

.gitignore

@@ -8,3 +8,4 @@ node_modules
 Thumbs.db
 
 /gobblr
+/examples/simple/migrations/simple

.gitpod.yml

@@ -1,13 +1,25 @@
 tasks:
+  - name: Build migration program
+    init: |
+      cd ./examples/simple/migrations
+      go build .
+    command: |
+      exit 0
+
   - name: MySQL
+    env:
+      DB_CONNECTION: "root:password@tcp(localhost:3306)/gobblr"
+      DB_TYPE: mysql
     command: |
       docker run \
         -e MYSQL_ROOT_PASSWORD=password \
         -e MYSQL_DATABASE=gobblr \
         --rm \
         -p 3306:3306 \
         --name mysql \
-        mysql
+        mysql &
+
+      ./examples/simple/migrations/simple
 
   - name: MongoDB
     command: |

examples/simple/data/001-users.json

@@ -0,0 +1,16 @@
+{
+  "meta": {
+    "createdKey": "created_at",
+    "updatedKey": "updated_at"
+  },
+  "data": [
+    {
+      "registered": true,
+      "confirmed": true,
+      "username": "test1",
+      "email_address": "test@test.com",
+      "name": "Test Testington",
+      "password": "13905934cb5503269ca5613b72a8aa8a:57a1846d12716308be489ec25f2a017e22aba88d591f5c5184e046cb42ec921f1ac5f5249b212efe5c8a644d45d7c63d3ee075cce79ba3a663c731971a56f4c3"
+    }
+  ]
+}

examples/simple/migrations/Dockerfile

@@ -0,0 +1,13 @@
+FROM golang AS builder
+WORKDIR /app
+ADD . .
+ENV CGO_ENABLED=0
+ENV GOOS=linux
+RUN go build -o /app/app
+ENTRYPOINT /app/app
+
+FROM alpine
+RUN apk --no-cache add ca-certificates
+WORKDIR /app
+COPY --from=builder /app/app /app
+ENTRYPOINT [ "/app/app" ]

examples/simple/migrations/go.mod

@@ -0,0 +1,15 @@
+module simple
+
+go 1.19
+
+require (
+	github.com/cenkalti/backoff/v4 v4.2.0
+	gorm.io/driver/mysql v1.4.4
+	gorm.io/gorm v1.24.2
+)
+
+require (
+	github.com/go-sql-driver/mysql v1.6.0 // indirect
+	github.com/jinzhu/inflection v1.0.0 // indirect
+	github.com/jinzhu/now v1.1.5 // indirect
+)

examples/simple/migrations/go.sum

@@ -0,0 +1,14 @@
+github.com/cenkalti/backoff/v4 v4.2.0 h1:HN5dHm3WBOgndBH6E8V0q2jIYIR3s9yglV8k/+MN3u4=
+github.com/cenkalti/backoff/v4 v4.2.0/go.mod h1:Y3VNntkOUPxTVeUxJ/G5vcM//AlwfmyYozVcomhLiZE=
+github.com/go-sql-driver/mysql v1.6.0 h1:BCTh4TKNUYmOmMUcQ3IipzF5prigylS7XXjEkfCHuOE=
+github.com/go-sql-driver/mysql v1.6.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
+github.com/jinzhu/inflection v1.0.0 h1:K317FqzuhWc8YvSVlFMCCUb36O/S9MCKRDI7QkRKD/E=
+github.com/jinzhu/inflection v1.0.0/go.mod h1:h+uFLlag+Qp1Va5pdKtLDYj+kHp5pxUVkryuEj+Srlc=
+github.com/jinzhu/now v1.1.4/go.mod h1:d3SSVoowX0Lcu0IBviAWJpolVfI5UJVZZ7cO71lE/z8=
+github.com/jinzhu/now v1.1.5 h1:/o9tlHleP7gOFmsnYNz3RGnqzefHA47wQpKrrdTIwXQ=
+github.com/jinzhu/now v1.1.5/go.mod h1:d3SSVoowX0Lcu0IBviAWJpolVfI5UJVZZ7cO71lE/z8=
+gorm.io/driver/mysql v1.4.4 h1:MX0K9Qvy0Na4o7qSC/YI7XxqUw5KDw01umqgID+svdQ=
+gorm.io/driver/mysql v1.4.4/go.mod h1:BCg8cKI+R0j/rZRQxeKis/forqRwRSYOR8OM3Wo6hOM=
+gorm.io/gorm v1.23.8/go.mod h1:l2lP/RyAtc1ynaTjFksBde/O8v9oOGIApu2/xRitmZk=
+gorm.io/gorm v1.24.2 h1:9wR6CFD+G8nOusLdvkZelOEhpJVwwHzpQOUM+REd6U0=
+gorm.io/gorm v1.24.2/go.mod h1:DVrVomtaYTbqs7gB/x2uVvqnXzv0nqjB396B8cG4dBA=

examples/simple/migrations/main.go

@@ -0,0 +1,72 @@
+// The SQL databases need to have the tables created before
+// we can do anything. Normally, this would be your own migration
+// package's responsibility, but this simulates it for our
+// purposes
+
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/cenkalti/backoff/v4"
+	"gorm.io/driver/mysql"
+	"gorm.io/gorm"
+)
+
+type User struct {
+	gorm.Model
+	Registered   bool
+	Confirmed    bool
+	Username     string
+	EmailAddress string
+	Name         string
+	Password     string
+}
+
+func execute(dialector gorm.Dialector) error {
+	db, err := gorm.Open(dialector, &gorm.Config{})
+	if err != nil {
+		return err
+	}
+
+	if err := db.AutoMigrate(&User{}); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func main() {
+	connection := os.Getenv("DB_CONNECTION")
+	dbType := os.Getenv("DB_TYPE")
+
+	var dialector gorm.Dialector
+	switch dbType {
+	case "mysql":
+		dialector = mysql.Open(connection)
+	default:
+		panic(fmt.Errorf("unknown db type: %s", dbType))
+	}
+
+	tries := 0
+
+	err := backoff.Retry(
+		func() error {
+			if tries > 0 {
+				fmt.Println("Retrying database connection...")
+			}
+			err := execute(dialector)
+
+			tries += 1
+
+			return err
+		},
+		backoff.NewExponentialBackOff(),
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println("Migration completed")
+}

go.work

@@ -0,0 +1,6 @@
+go 1.19
+
+use (
+	.
+	./examples/simple/migrations
+)

go.work.sum

@@ -0,0 +1,6 @@
+github.com/mattn/go-colorable v0.1.12 h1:jF+Du6AlPIjs2BiUiQlKOX0rt3SujHxPnksPKZbaA40=
+github.com/mattn/go-isatty v0.0.14 h1:yVuAays6BHfxijgZPzw+3Zlu5yQgKGP2/hcQbHb7S9Y=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
+golang.org/x/net v0.0.0-20221014081412-f15817d10f9b h1:tvrvnPFcdzp294diPnrdZZZ8XUt2Tyj7svb7X52iDuU=
+golang.org/x/sync v0.1.0 h1:wsuoTGHzEhffawBOhz5CYhcrV4IdKZbEyZjBMuTp12o=
+google.golang.org/protobuf v1.28.1 h1:d0NfwRgPtno5B1Wa6L2DAG+KivqkdutMf1UhdNx175w=