add skeleton gRPC server with HealthCheck

Relates to https://github.com/corgibytes/freshli-cli/issues/695

Author: doughertym

.gitignore

@@ -21,3 +21,4 @@
 go.work
 
 tmp/
+vendor/

agent/server/main.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"fmt"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/health"
+	healthgrpc "google.golang.org/grpc/health/grpc_health_v1"
+	"google.golang.org/grpc/reflection"
+	"log"
+	"net"
+	"os"
+	"strconv"
+)
+
+func main() {
+	port, err := parsePortArgument()
+	if err != nil || port < 0 {
+		log.Fatalf("port is required: %v", err)
+		return
+	}
+	log.Printf("gRPC server listening on %d", port)
+
+	lis, err := net.Listen("tcp", fmt.Sprintf(":%d", port))
+	if err != nil {
+		log.Fatalf("failed to listen: %v", err)
+	}
+	s := grpc.NewServer()
+	healthcheck := health.NewServer()
+	healthgrpc.RegisterHealthServer(s, healthcheck)
+
+	// TODO should this be only in dev/debug mode?
+	reflection.Register(s)
+
+	if err := s.Serve(lis); err != nil {
+		log.Fatalf("failed to serve: %v", err)
+	}
+}
+
+func parsePortArgument() (int, error) {
+	if len(os.Args) > 1 {
+		return strconv.Atoi(os.Args[1])
+	}
+	return -1, nil
+}

go.mod

@@ -7,6 +7,9 @@ toolchain go1.21.1
 require (
 	github.com/anchore/clio v0.0.0-20230823172630-c42d666061af
 	github.com/anchore/syft v0.91.0
+	github.com/golang/protobuf v1.5.3
+	google.golang.org/grpc v1.58.2
+	google.golang.org/protobuf v1.31.0
 	modernc.org/sqlite v1.25.0
 )
 
@@ -80,7 +83,6 @@ require (
 	github.com/go-restruct/restruct v1.2.0-alpha // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
-	github.com/golang/protobuf v1.5.3 // indirect
 	github.com/golang/snappy v0.0.4 // indirect
 	github.com/google/go-cmp v0.5.9 // indirect
 	github.com/google/go-containerregistry v0.16.1 // indirect
@@ -183,9 +185,8 @@ require (
 	golang.org/x/text v0.13.0 // indirect
 	golang.org/x/tools v0.13.0 // indirect
 	golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2 // indirect
-	google.golang.org/genproto v0.0.0-20230410155749-daa745c078e1 // indirect
-	google.golang.org/grpc v1.55.0 // indirect
-	google.golang.org/protobuf v1.30.0 // indirect
+	google.golang.org/genproto v0.0.0-20230711160842-782d3b101e98 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20230711160842-782d3b101e98 // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect
 	gopkg.in/warnings.v0 v0.1.2 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
@@ -197,5 +198,7 @@ require (
 	modernc.org/memory v1.6.0 // indirect
 	modernc.org/opt v0.1.3 // indirect
 	modernc.org/strutil v1.1.3 // indirect
-	modernc.org/token v1.0.1 // indirect
+	modernc.org/token v1.1.0 // indirect
 )
+
+replace google.golang.org/grpc => github.com/grpc/grpc-go v1.58.2