Merge pull request #3 from sv-tools/base

Add the first implementation

Author: SVilgelm

Dockerfile

@@ -1,4 +1,5 @@
 FROM scratch
 ENV CONFIG=config.yaml
+ENV PORT=8080
 ENTRYPOINT ["/mock-http-server"]
 COPY mock-http-server /

README.md

@@ -6,7 +6,7 @@
 [![GitHub tag (latest SemVer)](https://img.shields.io/github/v/tag/sv-tools/mock-http-server?style=flat)](https://github.com/sv-tools/mock-http-server/releases)
 
 A simple HTTP Server to be used for the unit or end-to-end to integrations tests.
-* yaml based configuration
+* yaml based configuration, see an `example_config.go`
 * docker image
 
 ## License

config.go

@@ -0,0 +1,79 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"os"
+)
+
+type Config struct {
+	RequestIDHeader string  `json:"request_id_header,omitempty" yaml:"request_id_header,omitempty"`
+	Routes          []Route `json:"routes" yaml:"routes"`
+	Port            int     `json:"port,omitempty" yaml:"port,omitempty"`
+}
+
+type Route struct {
+	Method    string     `json:"method,omitempty" yaml:"method,omitempty"`
+	Pattern   string     `json:"pattern,omitempty" yaml:"pattern,omitempty"`
+	Responses []Response `json:"responses" yaml:"responses"`
+}
+
+type Response struct {
+	Headers http.Header `json:"headers,omitempty" yaml:"headers,omitempty"`
+	Repeat  *int        `json:"repeat,omitempty" yaml:"repeat,omitempty"`
+	Body    string      `json:"body,omitempty" yaml:"body,omitempty"`
+	File    string      `json:"file,omitempty" yaml:"file,omitempty"`
+	Code    int         `json:"code,omitempty" yaml:"code,omitempty"`
+	IsJSON  bool        `json:"is_json,omitempty" yaml:"is_json,omitempty"`
+}
+
+func responsesWriter(responses []Response) http.HandlerFunc {
+	var i int
+	return func(writer http.ResponseWriter, request *http.Request) {
+		for {
+			if i > len(responses)-1 {
+				http.NotFound(writer, request)
+				return
+			}
+			response := responses[i]
+			if response.Repeat != nil {
+				if *response.Repeat <= 0 {
+					i++
+					continue
+				}
+				*response.Repeat--
+			}
+
+			var data []byte
+			if response.File != "" {
+				var err error
+				data, err = os.ReadFile(response.File)
+				if err != nil {
+					http.Error(writer, err.Error(), http.StatusInternalServerError)
+					return
+				}
+			} else if len(response.Body) > 0 {
+				data = []byte(response.Body)
+			}
+
+			for name, header := range response.Headers {
+				for _, value := range header {
+					writer.Header().Add(name, value)
+				}
+			}
+			if response.IsJSON {
+				if writer.Header().Get("Content-Type") == "" {
+					writer.Header().Set("Content-Type", "application/json")
+				}
+			}
+			writer.WriteHeader(response.Code)
+
+			if len(data) > 0 {
+				if _, err := writer.Write(data); err != nil {
+					log.Printf("sending response failed: %+v", err)
+				}
+			}
+			return
+		}
+	}
+}

config.schema.json

@@ -0,0 +1,83 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://raw.githubusercontent.com/sv-tools/mock-http-server/main/config.schema.json",
+  "title": "Mock HTTP Server Config Schema",
+  "description": "Schema to validate the config of the Mock HTTP Server",
+  "type": "object",
+  "properties": {
+    "port": {
+      "description": "The http port for the server",
+      "default": 8080,
+      "type": "integer"
+    },
+    "request_id_header": {
+      "description": "Name of an HTTP header for Request Id",
+      "default": "X-Request-Id",
+      "type": "string"
+    },
+    "routes": {
+      "description": "The list of routes",
+      "type": "array",
+      "items": {
+        "type": "object",
+        "properties": {
+          "method": {
+            "description": "The HTTP method, any of the standard or custom.",
+            "default": "GET",
+            "type": "string"
+          },
+          "pattern": {
+            "description": "An url pattern",
+            "default": "/",
+            "type": "string"
+          },
+          "responses": {
+            "description": "List of the responses",
+            "type": "array",
+            "items": {
+              "type": "object",
+              "properties": {
+                "code": {
+                  "description": "The response Status Code",
+                  "default": 200,
+                  "type": "integer"
+                },
+                "headers": {
+                  "description": "The response headers in form of name and list of values",
+                  "type": "object",
+                  "additionalProperties": {
+                    "type": "array",
+                    "items": {
+                      "type": "string"
+                    }
+                  }
+                },
+                "body": {
+                  "description": "The response body as text",
+                  "type": "string"
+                },
+                "file": {
+                  "description": "A path to a file to be used as response body",
+                  "type": "string"
+                },
+                "is_json": {
+                  "description": "A flag to automatically add the `Content-Type: application/json` response header",
+                  "default": false,
+                  "type": "boolean"
+                },
+                "repeat": {
+                  "description": "the number of repeats. Infinity if no set. Zero to skip. Or an exact number of repeats.",
+                  "type": "integer"
+                }
+              }
+            },
+            "minItems": 1
+          }
+        },
+        "required": ["responses"]
+      },
+      "minItems": 1
+    }
+  },
+  "required": ["routes"]
+}

example_config.yaml

@@ -0,0 +1,30 @@
+routes:
+  - method: get
+    pattern: /users
+    responses:
+      - code: 200
+        body: |
+          [
+            {
+              "name": "foo"
+            },
+            {
+              "name": "bar"
+            }
+          ]
+        is_json: true
+        repeat: 3
+      - code: 500
+        repeat: 1
+        body: "something is broken"
+      - code: 200
+        body: |
+          [
+            {
+              "name": "foo"
+            },
+            {
+              "name": "bar"
+            }
+          ]
+        is_json: true

go.mod

@@ -1,3 +1,9 @@
 module github.com/sv-tools/mock-http-server
 
 go 1.20
+
+require (
+	github.com/go-chi/chi/v5 v5.0.8
+	github.com/spf13/pflag v1.0.5
+	gopkg.in/yaml.v3 v3.0.1
+)

go.sum

@@ -0,0 +1,8 @@
+github.com/go-chi/chi/v5 v5.0.8 h1:lD+NLqFcAi1ovnVZpsnObHGW4xb4J8lNmoYVfECH1Y0=
+github.com/go-chi/chi/v5 v5.0.8/go.mod h1:DslCQbL2OYiznFReuXYUmQ2hGd1aDpCnlMNITLSKoi8=
+github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
+github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

@@ -0,0 +1,106 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"strconv"
+	"syscall"
+	"time"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/chi/v5/middleware"
+	flag "github.com/spf13/pflag"
+	"gopkg.in/yaml.v3"
+)
+
+func main() {
+	conf := flag.StringP("config", "c", "config.yaml", "config file")
+	port := flag.IntP("port", "p", 8080, "http port")
+	flag.Parse()
+
+	if v := os.Getenv("CONFIG"); v != "" && !flag.Lookup("config").Changed {
+		conf = &v
+	}
+	if v := os.Getenv("PORT"); v != "" && !flag.Lookup("port").Changed {
+		p, err := strconv.Atoi(v)
+		if err != nil {
+			log.Fatal(err)
+		}
+		port = &p
+	}
+
+	f, err := os.Open(*conf)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var config Config
+	d := yaml.NewDecoder(f)
+	d.KnownFields(true)
+	if err := d.Decode(&config); err != nil {
+		panic(err)
+	}
+	if config.Port != 0 {
+		port = &config.Port
+	}
+
+	if config.RequestIDHeader != "" {
+		middleware.RequestIDHeader = config.RequestIDHeader
+	}
+	r := chi.NewRouter().With(middleware.Logger, middleware.RequestID)
+	for _, route := range config.Routes {
+		if route.Method == "" {
+			route.Method = "GET"
+		} else {
+			chi.RegisterMethod(route.Method)
+		}
+		if route.Pattern == "" {
+			route.Pattern = "/"
+		}
+		r.MethodFunc(route.Method, route.Pattern, responsesWriter(route.Responses))
+	}
+
+	server := &http.Server{
+		Addr:              fmt.Sprintf(":%d", *port),
+		Handler:           r,
+		ReadHeaderTimeout: 1 * time.Second,
+	}
+	serverCtx, serverStopCtx := context.WithCancel(context.Background())
+	sig := make(chan os.Signal, 1)
+	signal.Notify(sig, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)
+	go func() {
+		<-sig
+
+		// Shutdown signal with grace period of 30 seconds
+		shutdownCtx, shutdownCancelCtx := context.WithTimeout(serverCtx, 30*time.Second)
+		defer shutdownCancelCtx()
+
+		go func() {
+			<-shutdownCtx.Done()
+			if errors.Is(shutdownCtx.Err(), context.DeadlineExceeded) {
+				log.Fatal("graceful shutdown timed out.. forcing exit.")
+			}
+		}()
+
+		// Trigger graceful shutdown
+		err := server.Shutdown(shutdownCtx)
+		if err != nil {
+			log.Fatal(err)
+		}
+		serverStopCtx()
+	}()
+
+	// Run the server
+	log.Printf("Listen on http://localhost:%d\n", *port)
+	if err := server.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
+		log.Fatal(err)
+	}
+
+	// Wait for server context to be stopped
+	<-serverCtx.Done()
+}