From 58710c23b2389f42e46bd84f5012e922b7bbc7a3 Mon Sep 17 00:00:00 2001
From: Timmelmann <41704604+Timmelmann@users.noreply.github.com>
Date: Sat, 8 Aug 2026 14:26:06 +0200
Subject: [PATCH] moved the kafka-go project to this repository

---
 README.md                            | 34 +++++++++++++++++++++++++
 app/protocol/request/body.go         | 35 ++++++++++++++++++++++++++
 app/protocol/request/header.go       | 19 ++++++++++++++
 app/protocol/response/message.go     |  7 ++++++
 app/protocol/response/v0_header.go   | 19 ++++++++++++++
 app/protocol/response/v0_response.go | 28 +++++++++++++++++++++
 app/server.go                        | 37 ++++++++++++++++++++++++++++
 codecrafters.yml                     | 11 +++++++++
 go.mod                               | 11 +++++++++
 go.sum                               |  0
 your_program.sh                      | 24 ++++++++++++++++++
 11 files changed, 225 insertions(+)
 create mode 100644 README.md
 create mode 100644 app/protocol/request/body.go
 create mode 100644 app/protocol/request/header.go
 create mode 100644 app/protocol/response/message.go
 create mode 100644 app/protocol/response/v0_header.go
 create mode 100644 app/protocol/response/v0_response.go
 create mode 100644 app/server.go
 create mode 100644 codecrafters.yml
 create mode 100644 go.mod
 create mode 100644 go.sum
 create mode 100755 your_program.sh

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..a9a521b
--- /dev/null
+++ b/README.md
@@ -0,0 +1,34 @@
+[![progress-banner](https://backend.codecrafters.io/progress/kafka/4eddd9dd-43a3-4d8f-bae7-2f6d7d8ec6bc)](https://app.codecrafters.io/users/Timmelmann?r=2qF)
+
+This is a starting point for Go solutions to the
+["Build Your Own Kafka" Challenge](https://codecrafters.io/challenges/kafka).
+
+In this challenge, you'll build a toy Kafka clone that's capable of accepting
+and responding to APIVersions & Fetch API requests. You'll also learn about
+encoding and decoding messages using the Kafka wire protocol. You'll also learn
+about handling the network protocol, event loops, TCP sockets and more.
+
+**Note**: If you're viewing this repo on GitHub, head over to
+[codecrafters.io](https://codecrafters.io) to try the challenge.
+
+# Passing the first stage
+
+The entry point for your Kafka implementation is in `app/server.go`. Study and
+uncomment the relevant code, and push your changes to pass the first stage:
+
+```sh
+git commit -am "pass 1st stage" # any msg
+git push origin master
+```
+
+That's all!
+
+# Stage 2 & beyond
+
+Note: This section is for stages 2 and beyond.
+
+1. Ensure you have `go (1.19)` installed locally
+1. Run `./your_program.sh` to run your Kafka broker, which is implemented in
+   `app/server.go`.
+1. Commit your changes and run `git push origin master` to submit your solution
+   to CodeCrafters. Test output will be streamed to your terminal.
diff --git a/app/protocol/request/body.go b/app/protocol/request/body.go
new file mode 100644
index 0000000..0636104
--- /dev/null
+++ b/app/protocol/request/body.go
@@ -0,0 +1,35 @@
+package protocol
+
+import "encoding/binary"
+
+type Request struct {
+	bytes []byte
+	byteParseOffset uint
+
+	Length int32
+	Header *RequestHeader
+}
+
+func NewRequest(bytes []byte) *Request {
+	req := Request{
+		bytes: bytes, 
+		byteParseOffset: 0,
+	}
+
+	req.Length = req.ReadInt32()
+	req.Header = ParseRequestHeader(&req)
+
+	return &req
+}
+
+func (r *Request) ReadInt16() int16{
+	val := binary.BigEndian.Uint16(r.bytes[r.byteParseOffset:])
+	r.byteParseOffset += 2
+	return int16(val)
+}
+
+func (r *Request) ReadInt32() int32 {
+	val := binary.BigEndian.Uint32(r.bytes[r.byteParseOffset:])
+	r.byteParseOffset += 4
+	return int32(val)
+}
diff --git a/app/protocol/request/header.go b/app/protocol/request/header.go
new file mode 100644
index 0000000..cf0f47b
--- /dev/null
+++ b/app/protocol/request/header.go
@@ -0,0 +1,19 @@
+package protocol
+
+type RequestHeader struct {
+	APIKey int16
+	APIVersion int16
+	Correlation_id int32
+}
+
+func ParseRequestHeader(r *Request) *RequestHeader {
+	apiKey := r.ReadInt16()
+	apiVersion := r.ReadInt16()
+	correlation_id := r.ReadInt32()
+
+	return &RequestHeader{
+		APIKey: apiKey,
+		APIVersion: apiVersion,
+		Correlation_id: correlation_id,
+	}
+}
\ No newline at end of file
diff --git a/app/protocol/response/message.go b/app/protocol/response/message.go
new file mode 100644
index 0000000..587636a
--- /dev/null
+++ b/app/protocol/response/message.go
@@ -0,0 +1,7 @@
+package response
+
+type Message struct {
+	body []byte
+	header V0Header
+	messageSize int32
+}
diff --git a/app/protocol/response/v0_header.go b/app/protocol/response/v0_header.go
new file mode 100644
index 0000000..4b66bb6
--- /dev/null
+++ b/app/protocol/response/v0_header.go
@@ -0,0 +1,19 @@
+package response
+
+import "encoding/binary"
+
+type V0Header struct {
+	Correlation_id uint32
+}
+
+func NewHeader(correlation_id uint32) *V0Header {
+	return &V0Header{
+		Correlation_id: correlation_id,
+	}
+}
+
+func (h *V0Header) ToBytes() []byte {
+	buf := make([]byte, 4)
+	binary.BigEndian.PutUint32(buf, uint32(h.Correlation_id))
+	return buf
+}
diff --git a/app/protocol/response/v0_response.go b/app/protocol/response/v0_response.go
new file mode 100644
index 0000000..17fbbbf
--- /dev/null
+++ b/app/protocol/response/v0_response.go
@@ -0,0 +1,28 @@
+package response
+
+import (
+	"encoding/binary"
+)
+
+type V0Response struct {
+	header V0Header
+	body  []byte
+}
+
+func NewV0Reponse(correlation_id uint32) *V0Response {
+	return &V0Response{
+		header: V0Header{
+			Correlation_id: correlation_id},
+		body: []byte{},
+	}
+}
+
+func (r *V0Response) ToBytes() []byte {
+	header := r.header.ToBytes()
+	length := len(header)
+	buf := make([]byte, length+4)
+	binary.BigEndian.PutUint32(buf[0:4], uint32(length))
+	copy(buf[4:], header)
+
+	return buf
+}
diff --git a/app/server.go b/app/server.go
new file mode 100644
index 0000000..4a15068
--- /dev/null
+++ b/app/server.go
@@ -0,0 +1,37 @@
+package main
+
+import (
+	"fmt"
+	"net"
+	"os"
+
+	protocol "github.com/codecrafters-io/redis-starter-go/app/protocol/response"
+)
+
+// Ensures gofmt doesn't remove the "net" and "os" imports in stage 1 (feel free to remove this!)
+var _ = net.Listen
+var _ = os.Exit
+
+func main() {
+
+	l, err := net.Listen("tcp", "0.0.0.0:9092")
+	if err != nil {
+		fmt.Println("Failed to bind to port 9092: ", err.Error())
+		os.Exit(1)
+	}
+	conn, err := l.Accept()
+	if err != nil {
+		fmt.Println("Could not accept connection: ", err.Error())
+		os.Exit(1)
+	}
+	defer conn.Close()
+
+	if _, err = conn.Read(make([]byte, 1024)); err != nil {
+		fmt.Println("Failed to read request: ", err.Error())
+	}
+
+	response := protocol.NewV0Reponse(7)
+	if _, err = conn.Write(response.ToBytes()); err != nil {
+		fmt.Println("Failed to write response: ", err.Error())
+	}
+}
diff --git a/codecrafters.yml b/codecrafters.yml
new file mode 100644
index 0000000..77886cf
--- /dev/null
+++ b/codecrafters.yml
@@ -0,0 +1,11 @@
+# Set this to true if you want debug logs.
+#
+# These can be VERY verbose, so we suggest turning them off
+# unless you really need them.
+debug: false
+
+# Use this to change the Go version used to run your code
+# on Codecrafters.
+#
+# Available versions: go-1.22
+language_pack: go-1.22
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..a8e2d2a
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,11 @@
+// DON'T EDIT THIS!
+//
+// Codecrafters relies on this file being intact to run tests successfully. Any changes
+// here will not reflect when CodeCrafters tests your code, and might even cause build
+// failures.
+//
+// DON'T EDIT THIS!
+
+module github.com/codecrafters-io/redis-starter-go
+
+go 1.22
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..e69de29
diff --git a/your_program.sh b/your_program.sh
new file mode 100755
index 0000000..8b5fdeb
--- /dev/null
+++ b/your_program.sh
@@ -0,0 +1,24 @@
+#!/bin/sh
+#
+# Use this script to run your program LOCALLY.
+#
+# Note: Changing this script WILL NOT affect how CodeCrafters runs your program.
+#
+# Learn more: https://codecrafters.io/program-interface
+
+set -e # Exit early if any commands fail
+
+# Copied from .codecrafters/compile.sh
+#
+# - Edit this to change how your program compiles locally
+# - Edit .codecrafters/compile.sh to change how your program compiles remotely
+(
+  cd "$(dirname "$0")" # Ensure compile steps are run within the repository directory
+  go build -o /tmp/codecrafters-build-redis-go app/*.go
+)
+
+# Copied from .codecrafters/run.sh
+#
+# - Edit this to change how your program runs locally
+# - Edit .codecrafters/run.sh to change how your program runs remotely
+exec /tmp/codecrafters-build-redis-go "$@"