Initial commit

.gitignore

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+.idea/**
+template
+.env

README.md

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+# go-web-app-template
+
+Basic template for creating go applications
+
+Includes:
+ * dotenv
+ * pq
+ * sqlx
+ * chi
+ * google.uuid
+
+To start using make sure to setup either environment variables listed
+below, or create .env file and copy variables below
+```
+PSQL_HOST=localhost
+PSQL_PORT=5432
+PSQL_USER=template
+PSQL_PASSWORD=templatePassword
+PSQL_DB=template
+```
+
+Also, database is required for template to start, so you can start it with `docker compose up -d`

db.go

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+package main
+
+import (
+	"fmt"
+	"github.com/jmoiron/sqlx"
+	_ "github.com/lib/pq"
+	"os"
+)
+
+func envMustExist(env string) string {
+	if value, exists := os.LookupEnv(env); !exists {
+		panic(fmt.Sprintf("env variable '%s' not defined", env))
+	} else {
+		return value
+	}
+}
+
+func connectToDb() (*sqlx.DB, error) {
+	host := envMustExist("PSQL_HOST")
+	port := envMustExist("PSQL_PORT")
+	user := envMustExist("PSQL_USER")
+	password := envMustExist("PSQL_PASSWORD")
+	dbname := envMustExist("PSQL_DB")
+
+	psqlInfo := fmt.Sprintf("host=%s port=%s user=%s password=%s dbname=%s sslmode=disable",
+		host, port, user, password, dbname)
+
+	db, err := sqlx.Open("postgres", psqlInfo)
+	if err != nil {
+		return nil, err
+	}
+
+	err = db.Ping()
+	if err != nil {
+		return nil, err
+	}
+
+	return db, nil
+}

db/prod/v1_0.sql

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+package prod

docker-compose-deploy.yml

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+version: '3.1'
+
+services:
+    backend:
+        image: registry.bbr-dev.info/template/backend:latest
+        restart: on-failure
+        depends_on:
+            - database
+        ports:
+            - "5281:5281"
+        networks:
+            - template
+        env_file:
+            - .env.docker
+
+    database:
+        image: postgres:14
+        ports:
+            - "5432:5432"
+        environment:
+            - POSTGRES_USER=template
+            - POSTGRES_PASSWORD=templatePassword
+            - POSTGRES_DB=template
+        networks:
+            - template
+
+networks:
+    template:

docker-compose.yml

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+version: '3.1'
+
+services:
+    database:
+        image: postgres:14
+        ports:
+            - "5432:5432"
+        environment:
+            - POSTGRES_USER=template
+            - POSTGRES_PASSWORD=templatePassword
+            - POSTGRES_DB=template

dockerfile

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+### STAGE 1.a: Prepare certs ###
+FROM alpine:latest as certs
+RUN apk --update add ca-certificates
+
+### STAGE 1.b: Build ###
+FROM golang as go-build
+WORKDIR /root
+COPY go.mod go.sum ./
+# install packages
+RUN go mod download
+COPY . .
+ENV CGO_ENABLED=0
+RUN go build -tags timetzdata template
+
+### Stage 2: Run ###
+FROM scratch
+COPY --from=certs /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/ca-certificates.crt
+COPY --from=go-build /root/template /usr/bin/template
+ENTRYPOINT ["template"]

go.mod

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+module template
+
+go 1.19
+
+require (
+	github.com/go-chi/chi v1.5.4
+	github.com/jmoiron/sqlx v1.3.5
+	github.com/joho/godotenv v1.5.1
+	github.com/lib/pq v1.10.9
+	github.com/google/uuid v1.3.0 // indirect
+)

go.sum

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+github.com/go-chi/chi v1.5.4 h1:QHdzF2szwjqVV4wmByUnTcsbIg7UGaQ0tPF2t5GcAIs=
+github.com/go-chi/chi v1.5.4/go.mod h1:uaf8YgoFazUOkPBG7fxPftUylNumIev9awIWOENIuEg=
+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/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
+github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/jmoiron/sqlx v1.3.5 h1:vFFPA71p1o5gAeqtEAwLU4dnX2napprKtHr7PYIcN3g=
+github.com/jmoiron/sqlx v1.3.5/go.mod h1:nRVWtLre0KfCLJvgxzCsLVMogSvQ1zNJtpYr2Ccp0mQ=
+github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
+github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
+github.com/lib/pq v1.2.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
+github.com/lib/pq v1.10.9 h1:YXG7RB+JIjhP29X+OtkiDnYaXQwpS4JEWq7dtCCRUEw=
+github.com/lib/pq v1.10.9/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
+github.com/mattn/go-sqlite3 v1.14.6 h1:dNPt6NO46WmLVt2DLNpwczCmdV5boIZ6g/tlDrlRUbg=
+github.com/mattn/go-sqlite3 v1.14.6/go.mod h1:NyWgC/yNuGj7Q9rpYnZvas74GogHl5/Z4A/KQRfk6bU=

main.go

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+package main
+
+import (
+	"embed"
+	"github.com/go-chi/chi"
+	"github.com/go-chi/chi/middleware"
+	"github.com/joho/godotenv"
+	"log"
+	"net/http"
+	"template/migration"
+)
+
+//go:embed db/dev/*.sql
+var devMigrations embed.FS
+
+func init() {
+	godotenv.Load()
+	log.SetPrefix("")
+	log.SetFlags(log.Ldate | log.Ltime | log.Lshortfile)
+}
+
+func main() {
+	client, err := connectToDb()
+	if err != nil {
+		log.Fatalf("couldn't connect to db: %v", err)
+	}
+	if err := migration.InitializeMigrations(client, devMigrations); err != nil {
+		log.Fatalf("couldn't execute migrations: %v", err)
+	}
+
+	r := chi.NewRouter()
+	r.Use(middleware.RequestID)
+	r.Use(middleware.RealIP)
+	r.Use(middleware.Logger)
+	r.Use(middleware.Recoverer)
+
+	r.Get("/", helloWorld)
+
+	log.Fatal(http.ListenAndServe(":5281", r))
+}
+
+func helloWorld(w http.ResponseWriter, r *http.Request) {
+	response := struct {
+		Title   string `json:"title"`
+		Message string `json:"message"`
+	}{Title: "hello world", Message: "this is an example of response"}
+
+	render(w, r, http.StatusOK, response)
+}

makefile

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+# scripts for building app
+# requires go 1.19+ and git installed
+
+VERSION := 0.0.1
+
+serve:
+	go run ./...
+
+setup:
+	go get
+
+docker-dev:
+	docker image build -t registry.bbr-dev.info/template/backend:$(VERSION)-dev .
+	docker tag registry.bbr-dev.info/template/backend:$(VERSION)-dev registry.bbr-dev.info/template/backend:latest-dev
+	docker image push registry.bbr-dev.info/template/backend:$(VERSION)-dev
+	docker image push registry.bbr-dev.info/template/backend:latest-dev
+	
+
+docker-prod:
+	docker image build -t registry.bbr-dev.info/template/backend:$(VERSION) .
+	docker tag registry.bbr-dev.info/template/backend:$(VERSION) registry.bbr-dev.info/template/backend:latest
+	docker image push registry.bbr-dev.info/template/backend:$(VERSION)
+	docker image push registry.bbr-dev.info/template/backend:latest
+
+release:
+	git tag $(VERSION)
+	git push origin $(VERSION)
+
+test:
+	go test ./...
+
+clean:
+	rm -rf template

migration/migration.go

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+package migration
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+	"github.com/jmoiron/sqlx"
+	"io/fs"
+	"log"
+	"sort"
+	"strings"
+	"time"
+)
+
+const migrationsTable = `
+CREATE TABLE IF NOT EXISTS migration (
+    filename varchar,
+    hash varchar,
+    created timestamp,
+    should_validate boolean
+);`
+const fetchMigrationsTable = `SELECT * FROM "migration";`
+const createMigration = `INSERT INTO "migration" (filename, hash, created, should_validate) VALUES  ($1, $2, current_timestamp, TRUE);`
+
+type Migration struct {
+	Filename       string    `db:"filename"`
+	Hash           string    `db:"hash"`
+	Created        time.Time `db:"created"`
+	ShouldValidate bool      `db:"should_validate"`
+}
+
+func InitializeMigrations(db *sqlx.DB, migrationFiles fs.FS) error {
+	// create table if it doesn't exist already
+	if _, err := db.Exec(migrationsTable); err != nil {
+		return err
+	}
+
+	// fetch current migrations
+	var entries []Migration
+	if err := db.Select(&entries, fetchMigrationsTable); err != nil {
+		return err
+	}
+
+	migrations := map[string]Migration{}
+	for _, entry := range entries {
+		migrations[entry.Filename] = entry
+	}
+	return validateMigrations(db, migrations, migrationFiles)
+}
+
+type version struct {
+	major int
+	minor int
+}
+
+func validateMigrations(db *sqlx.DB, migrations map[string]Migration, migrationFiles fs.FS) error {
+	scripts := map[string]string{}
+	var scriptNames []string
+
+	// fetch scripts
+	err := fs.WalkDir(migrationFiles, ".", func(path string, d fs.DirEntry, outerErr error) error {
+		if !d.IsDir() {
+			if bytearr, err := fs.ReadFile(migrationFiles, path); err == nil {
+				scripts[d.Name()] = strings.TrimSpace(string(bytearr))
+				scriptNames = append(scriptNames, d.Name())
+			}
+		}
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+
+	// sort scripts by version
+	sort.Slice(scriptNames, func(i, j int) bool {
+		return isLessThan(parseVersion(scriptNames[i]), parseVersion(scriptNames[j]))
+	})
+
+	for _, name := range scriptNames {
+		if _, exists := migrations[name]; exists {
+			if err := validateMigration(name, migrations[name], scripts[name]); err != nil {
+				return err
+			}
+		} else {
+			if err := executeMigration(db, name, scripts[name]); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func executeMigration(db *sqlx.DB, name string, script string) error {
+	log.Printf("[INFO] script='%s' | migrations - executing", name)
+	tx := db.MustBeginTx(context.Background(), nil)
+	var err error = nil
+	if _, e := tx.Exec(script); e != nil {
+		err = e
+	}
+	if _, e := tx.Exec(createMigration, name, hash(script)); e != nil {
+		err = e
+	}
+	if err != nil {
+		log.Printf("[ERROR] script='%s' | migrations - failed executing", name)
+		tx.Rollback()
+	} else {
+		log.Printf("[INFO] script='%s' | migrations - succesfully executed", name)
+		tx.Commit()
+	}
+	return err
+}
+
+func validateMigration(name string, migration Migration, script string) error {
+	if !migration.ShouldValidate {
+		return nil
+	}
+
+	calculatedHash := hash(script)
+
+	if calculatedHash != migration.Hash {
+		err := fmt.Sprintf("migrations - mismatch in hash for %s (expected '%s', calculated '%s')", name, migration.Hash, calculatedHash)
+		log.Printf("[ERROR] script='%s' err='%s' | migrations - failed executing", script, err)
+		return fmt.Errorf("migrations - mismatch in hashes for %s", name)
+	}
+	return nil
+}
+
+func hash(script string) string {
+	hash := sha256.New()
+	hash.Write([]byte(script))
+	return base64.StdEncoding.EncodeToString(hash.Sum(nil))
+}
+
+func isLessThan(v1 version, v2 version) bool {
+	if v1.major > v2.major {
+		return false
+	}
+	if v1.major == v2.major && v1.minor > v2.minor {
+		return false
+	}
+	return true
+}
+
+func parseVersion(filename string) version {
+	ver := version{}
+	if _, err := fmt.Sscanf(filename, "v%d_%d", &ver.major, &ver.minor); err != nil {
+		panic(err)
+	}
+	return ver
+}

render.go

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+package main
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+)
+
+func render[T any](w http.ResponseWriter, r *http.Request, status int, response T) error {
+	if body, err := json.MarshalIndent(response, "", "  "); err == nil {
+		w.Header().Add("content-type", "application/json")
+		w.WriteHeader(status)
+		_, err = w.Write(body)
+		return err
+	} else {
+		w.WriteHeader(http.StatusInternalServerError)
+		log.Printf("couldn't parse response")
+		_, err = w.Write([]byte{})
+		return err
+	}
+}