Add gRPC-support

Dockerfile

@@ -1,9 +1,15 @@
+FROM golang:1.23-alpine AS deps
+COPY go.mod go.sum ./
+RUN go mod download
+
 FROM golang:1.23-alpine AS golang-with-curl
 RUN apk --no-cache add curl
 
 FROM golang-with-curl
 WORKDIR /app
+COPY --from=deps /go/pkg/mod /go/pkg/mod
 COPY go.mod .
+COPY go.sum .
 COPY common common
 
 ARG DAY

common/env/env.go

@@ -0,0 +1,26 @@
+package env
+
+import "os"
+
+const (
+	HttpPrefix = "AOC2024_HTTP_PREFIX"
+	HttpPort   = "AOC2024_HTTP_PORT"
+	GrpcPort   = "AOC2024_GRPC_PORT"
+)
+
+func GetString(
+	key string,
+) string {
+	return os.Getenv(key)
+}
+
+func GetStringOrDefault(
+	key string,
+	def string,
+) string {
+	v := os.Getenv(key)
+	if v == "" {
+		return def
+	}
+	return v
+}

common/proto/adventservice.proto

@@ -0,0 +1,18 @@
+syntax = "proto3";
+package adventservice;
+
+option go_package = "github.com/terminalnode/adventofcode2024/common/proto";
+
+
+service AdventService {
+  rpc SolvePart1 (InputData) returns (InputResponse);
+  rpc SolvePart2 (InputData) returns (InputResponse);
+}
+
+message InputData {
+  string input = 1;
+}
+
+message InputResponse {
+  string result = 1;
+}