Add test network agent for ncproxy dev work

Signed-off-by: Kathryn Baldauf <kabaldau@microsoft.com>

cmd/networkagent/defs.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"encoding/json"
+	"io/ioutil"
+
+	"github.com/Microsoft/hcsshim/cmd/ncproxy/ncproxygrpc"
+	"github.com/pkg/errors"
+)
+
+type service struct {
+	conf                            *config
+	client                          ncproxygrpc.NetworkConfigProxyClient
+	containerToNamespace            map[string]string
+	endpointToNicID                 map[string]string
+	containerToNICVirtualFunctionID map[string]string
+	containerToNetwork              map[string]string
+}
+
+type nicWithVFSettings struct {
+	ID                   string `json:"id,omitempty"`
+	VirtualFunctionIndex uint32 `json:"virtual_function_index,omitempty"`
+}
+
+type hnsSettings struct {
+	SwitchName  string                                `json:"switch_name,omitempty"`
+	IOVSettings *ncproxygrpc.IovEndpointPolicySetting `json:"iov_settings,omitempty"`
+}
+
+type networkingSettings struct {
+	NICWithVFSettings *nicWithVFSettings `json:"nic_with_vf_settings,omitempty"`
+	HNSSettings       *hnsSettings       `json:"hns_settings,omitempty"`
+}
+
+type config struct {
+	TTRPCAddr      string `json:"ttrpc,omitempty"`
+	GRPCAddr       string `json:"grpc,omitempty"`
+	NodeNetSvcAddr string `json:"node_net_svc_addr,omitempty"`
+	// 0 represents no timeout and ncproxy will continuously try and connect in the
+	// background.
+	Timeout            uint32              `json:"timeout,omitempty"`
+	NetworkingSettings *networkingSettings `json:"networking_settings,omitempty"`
+}
+
+// Reads config from path and returns config struct if path is valid and marshaling
+// succeeds
+func readConfig(path string) (*config, error) {
+	data, err := ioutil.ReadFile(path)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to read config file")
+	}
+	conf := &config{}
+	if err := json.Unmarshal(data, conf); err != nil {
+		return nil, errors.New("failed to unmarshal config data")
+	}
+	return conf, nil
+}