session 6

Author: tebeka

README.md

@@ -299,4 +299,38 @@ Miki Tebeka
 - [Secure Code Slides](_extra/secure-go.pdf)
 - [journal.tar.gz](_extra/journal.tar.gz)
 
+---
+## Session 6: Testing
+
+### Agenda
+
+- Running services
+- Mocking and when to avoid them
+- Reading test data from files
+- Fuzzing
+
+### Code
+
+- [unter](session_6/unter)
+
+### Links
+
+- Linters
+    - [staticcheck](https://staticcheck.dev/)
+    - [golangci-lint](https://golangci-lint.run/)
+    - [x/tools/analysis](https://pkg.go.dev/golang.org/x/tools/go/analysis) - Write your own
+- [Getting Started with Fuzzing](https://go.dev/doc/tutorial/fuzz)
+- [Testcontainers for Go](https://golang.testcontainers.org/)
+- [distroless](https://github.com/GoogleContainerTools/distroless) - Hardened Docker images
+- [go-faker](https://github.com/go-faker/faker/blob/main/example_with_tags_test.go) - Generate fake data (email ...)
+- [RESP Client for VSCode](https://marketplace.visualstudio.com/items?itemName=humao.rest-client)
+
+
+### Data & Other
+
+```
+¯\_(ツ)_/¯
+```
+
+
 ![](https://pixel-73339669570.me-west1.run.app/p/para1/p.png)

session_6/unter/.gitignore

@@ -0,0 +1 @@
+*.db

session_6/unter/Dockerfile

@@ -0,0 +1,16 @@
+FROM golang:1.25 AS build
+WORKDIR /app
+COPY go.* ./
+RUN go mod download
+COPY . .
+ENV CGO_ENABLED=0
+RUN go build -o unter
+
+FROM debian:trixie-slim
+COPY --from=build /app/unter /usr/local/bin
+RUN groupadd -r unter && useradd --no-log-init -r -g unter unter
+RUN mkdir /opt/unter
+RUN chown unter /opt/unter
+ENV UNTER_DB=/opt/unter/unter.db
+USER unter
+CMD ["unter"]

session_6/unter/Makefile

@@ -0,0 +1,8 @@
+tag = unter/httpd
+
+build-docker:
+	docker build -t $(tag) .
+
+
+run-docker:
+	docker run --rm -p 8080:8080 $(tag)

session_6/unter/api.go

@@ -0,0 +1,76 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"net/http"
+)
+
+type API struct {
+	log *slog.Logger
+	db  *DB
+}
+
+func (a *API) Health(w http.ResponseWriter, r *http.Request) {
+	// TODO: Health check
+	fmt.Fprintln(w, "OK")
+}
+
+func (a *API) Add(w http.ResponseWriter, r *http.Request) {
+	var rd Ride
+	if err := json.NewDecoder(r.Body).Decode(&rd); err != nil {
+		a.log.Error("decode", "error", err)
+		http.Error(w, "bad record", http.StatusBadRequest)
+		return
+	}
+
+	if err := rd.Validate(); err != nil {
+		a.log.Error("validate", "error", err)
+		http.Error(w, "bad record", http.StatusBadRequest)
+		return
+	}
+
+	if err := a.db.Insert(rd); err != nil {
+		a.log.Error("insert", "error", err)
+		http.Error(w, "can't insert", http.StatusInternalServerError)
+		return
+	}
+	a.log.Info("added", "id", rd.ID)
+
+	resp := map[string]any{
+		"id": rd.ID,
+	}
+	a.sendJSON(w, resp)
+}
+
+func (a *API) Get(w http.ResponseWriter, r *http.Request) {
+	id := r.PathValue("id")
+	if id == "" {
+		http.Error(w, "missing ID", http.StatusBadRequest)
+		return
+	}
+
+	rd, err := a.db.Get(id)
+	if err != nil {
+		a.log.Error("scan", "error", err)
+		http.Error(w, "can't get rides", http.StatusInternalServerError)
+		return
+	}
+
+	resp := map[string]any{
+		"id":       rd.ID,
+		"distance": rd.Distance,
+		"shared":   rd.Shared,
+		"price":    RidePrice(rd.Distance, rd.Shared),
+	}
+	a.sendJSON(w, resp)
+}
+
+func (a *API) sendJSON(w http.ResponseWriter, resp any) {
+	w.Header().Set("content-type", "application/json")
+	if err := json.NewEncoder(w).Encode(resp); err != nil {
+		a.log.Error("encode", "error", err)
+		return
+	}
+}

session_6/unter/backoffice.go

@@ -0,0 +1,15 @@
+package main
+
+import "math"
+
+// RidePrice returns ride price in ¢
+func RidePrice(distance float64, shared bool) int {
+	price := 250 // initial fare
+	price += int(math.Ceil(distance)) * 150
+
+	if shared {
+		price = int(float64(price) * 0.9)
+	}
+
+	return price
+}

session_6/unter/client.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+)
+
+type Client struct {
+	baseURL string
+	c       http.Client
+}
+
+func NewClient(baseURL string) Client {
+	return Client{baseURL: baseURL}
+}
+
+func (c *Client) Health() error {
+	url, err := url.JoinPath(c.baseURL, "/health")
+	if err != nil {
+		return err
+	}
+
+	resp, err := c.c.Get(url)
+	if err != nil {
+		return err
+	}
+
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("%s: bad status - %s", url, resp.Status)
+	}
+
+	return nil
+}

session_6/unter/db.go

@@ -0,0 +1,78 @@
+package main
+
+import (
+	"bytes"
+	"encoding/gob"
+	"fmt"
+
+	"go.etcd.io/bbolt"
+)
+
+var (
+	bucketName = []byte("rides")
+)
+
+type DB struct {
+	conn *bbolt.DB
+}
+
+func NewDB(fileName string) (*DB, error) {
+	conn, err := bbolt.Open(fileName, 0666, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	err = conn.Update(func(tx *bbolt.Tx) error {
+		_, err := tx.CreateBucketIfNotExists(bucketName)
+		return err
+	})
+
+	if err != nil {
+		conn.Close()
+		return nil, err
+	}
+
+	db := DB{conn}
+	return &db, nil
+}
+
+func (db *DB) Close() error {
+	return db.conn.Close()
+}
+
+func (db *DB) Insert(r Ride) error {
+	var buf bytes.Buffer
+	if err := gob.NewEncoder(&buf).Encode(r); err != nil {
+		return err
+	}
+
+	err := db.conn.Update(func(tx *bbolt.Tx) error {
+		b := tx.Bucket(bucketName)
+		return b.Put([]byte(r.ID), buf.Bytes())
+	})
+	return err
+}
+
+func (db *DB) Get(id string) (Ride, error) {
+	var r Ride
+
+	err := db.conn.View(func(tx *bbolt.Tx) error {
+		b := tx.Bucket(bucketName)
+		data := b.Get([]byte(id))
+		if data == nil {
+			return fmt.Errorf("%q not found", id)
+		}
+
+		if err := gob.NewDecoder(bytes.NewReader(data)).Decode(&r); err != nil {
+			return err
+		}
+
+		return nil
+	})
+
+	if err != nil {
+		return Ride{}, err
+	}
+
+	return r, nil
+}

session_6/unter/go.mod

@@ -0,0 +1,67 @@
+module unter
+
+go 1.25
+
+require (
+	github.com/goccy/go-yaml v1.19.1
+	github.com/stretchr/testify v1.11.1
+	github.com/testcontainers/testcontainers-go v0.40.0
+	go.etcd.io/bbolt v1.4.3
+)
+
+require (
+	dario.cat/mergo v1.0.2 // indirect
+	github.com/Azure/go-ansiterm v0.0.0-20210617225240-d185dfc1b5a1 // indirect
+	github.com/Microsoft/go-winio v0.6.2 // indirect
+	github.com/cenkalti/backoff/v4 v4.3.0 // indirect
+	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/containerd/errdefs v1.0.0 // indirect
+	github.com/containerd/errdefs/pkg v0.3.0 // indirect
+	github.com/containerd/log v0.1.0 // indirect
+	github.com/containerd/platforms v0.2.1 // indirect
+	github.com/cpuguy83/dockercfg v0.3.2 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/distribution/reference v0.6.0 // indirect
+	github.com/docker/docker v28.5.1+incompatible // indirect
+	github.com/docker/go-connections v0.6.0 // indirect
+	github.com/docker/go-units v0.5.0 // indirect
+	github.com/ebitengine/purego v0.8.4 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
+	github.com/go-logr/logr v1.4.3 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/go-ole/go-ole v1.2.6 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	github.com/klauspost/compress v1.18.0 // indirect
+	github.com/lufia/plan9stats v0.0.0-20211012122336-39d0f177ccd0 // indirect
+	github.com/magiconair/properties v1.8.10 // indirect
+	github.com/moby/docker-image-spec v1.3.1 // indirect
+	github.com/moby/go-archive v0.1.0 // indirect
+	github.com/moby/patternmatcher v0.6.0 // indirect
+	github.com/moby/sys/sequential v0.6.0 // indirect
+	github.com/moby/sys/user v0.4.0 // indirect
+	github.com/moby/sys/userns v0.1.0 // indirect
+	github.com/moby/term v0.5.0 // indirect
+	github.com/morikuni/aec v1.0.0 // indirect
+	github.com/opencontainers/go-digest v1.0.0 // indirect
+	github.com/opencontainers/image-spec v1.1.1 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/power-devops/perfstat v0.0.0-20210106213030-5aafc221ea8c // indirect
+	github.com/shirou/gopsutil/v4 v4.25.6 // indirect
+	github.com/sirupsen/logrus v1.9.3 // indirect
+	github.com/tklauser/go-sysconf v0.3.12 // indirect
+	github.com/tklauser/numcpus v0.6.1 // indirect
+	github.com/yusufpapurcu/wmi v1.2.4 // indirect
+	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.49.0 // indirect
+	go.opentelemetry.io/otel v1.39.0 // indirect
+	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.39.0 // indirect
+	go.opentelemetry.io/otel/metric v1.39.0 // indirect
+	go.opentelemetry.io/otel/sdk v1.39.0 // indirect
+	go.opentelemetry.io/otel/trace v1.39.0 // indirect
+	go.opentelemetry.io/proto/otlp v1.9.0 // indirect
+	golang.org/x/crypto v0.43.0 // indirect
+	golang.org/x/sys v0.39.0 // indirect
+	google.golang.org/protobuf v1.36.10 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)