proto: Add example.cpp to get working JSON serialization

proto/Makefile

@@ -17,7 +17,8 @@ CPP_FILES   := $(CPP_SOURCE) $(CPP_HDR)
 DOCKER      ?= docker
 CWD         := $(shell pwd)
 
-default: example
+default: example_cpp
+	./example_cpp
 
 all: go py c cpp
 
@@ -42,6 +43,10 @@ $(CPP_DIR)/%.pb.cc: %.proto
 	@mkdir -p $(CPP_DIR)
 	protoc --cpp_out=$(CPP_DIR)/ $^
 
+%_cpp: %.cc $(CPP_FILES)
+	pkg-config --cflags protobuf  # fails if protobuf is not installed
+	c++ $< $(filter %.cc, $(CPP_FILES)) -o $@ $$(pkg-config --cflags --libs protobuf) -I $(CPP_DIR)
+
 py: $(PY_FILES)
 
 $(PY_DIR)/%_pb2.py: %.proto
@@ -52,5 +57,4 @@ proto3: Dockerfile run.sh
 	$(DOCKER) build -t $@ . && $(DOCKER) run -it -v $(CWD):/proto:ro -v $(CWD)/output:/output:rw $@
 
 clean:
-	rm -rf *~ $(GO_FILES) $(C_FILES) $(PY_FILES) $(CPP_FILES) $(CWD)/output
-
+	rm -rf *~ *_cpp $(GO_FILES) $(C_FILES) $(PY_FILES) $(CPP_FILES) $(CWD)/output

proto/config.json

@@ -0,0 +1,35 @@
+{
+  "version": "0.1.0",
+  "platform": {
+    "os": "linux",
+    "arch": "amd64"
+  },
+  "process": {
+    "terminal": true,
+    "user": {
+      "@type": "type.googleapis.com/oci.LinuxUser",
+      "uid": 1,
+      "gid": 1,
+      "additionalGids": [
+        5,
+        6
+      ]
+    },
+    "args": [
+      "sh"
+    ],
+    "env": [
+      "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
+      "TERM=linux"
+    ],
+    "cwd": "/root"
+  },
+  "hostname": "mrsdalloway",
+  "linuxx": {
+    "capabilities": [
+      "CAP_AUDIT_WRITE",
+      "CAP_KILL",
+      "CAP_NET_BIND_SERVICE"
+    ]
+  }
+}

proto/config.proto

@@ -1,30 +1,27 @@
+syntax = "proto3";
+
 package oci;
 
+import "google/protobuf/any.proto";
+
 // Spec is the base configuration for the container. It specifies platform
 // independent configuration.
 message Spec {
 	// Version is the version of the specification that is supported.
-	optional string version = 1;
+	string version = 1;
 	// Platform is the host information for OS and Arch.
-	optional Platform platform = 2;
+	Platform platform = 2;
 	// Process is the container's main process.
-	optional Process process = 3;
+	Process process = 3;
 	// Root is the root information for the container's filesystem.
-	optional Root root = 4;
+	Root root = 4;
 	// Hostname is the container's host name.
-	optional string hostname = 5;
+	string hostname = 5;
 	// Mounts profile configuration for adding mounts to the container's
 	// filesystem.
 	repeated MountPoint mounts = 6;
-}
-
-
-// LinuxSpec is the full specification for linux containers.
-message LinuxSpec {
-	optional Spec spec = 1;
-	// LinuxConfig is platform specific configuration for linux based
-	// containers.
-	optional LinuxConfig linux_config = 2;
+	// LinuxConfig is the Linux-specific, host-independent configuration.
+	LinuxConfig linuxx = 7;
 }
 
 // LinuxConfig contains platform specific configuration for linux based
@@ -38,69 +35,54 @@ message LinuxConfig {
 // container is created for.
 message Platform {
 	// OS is the operating system.
-	optional string os = 1;
+	string os = 1;
 	// Arch is the architecture
-	optional string arch = 2;
+	string arch = 2;
 }
 
 // Process contains information to start a specific application inside the
 // container.
 message Process {
 	// Terminal creates an interactive terminal for the container.
-	optional bool terminal = 1;
+	bool terminal = 1;
 	// User specifies user information for the process.
-	optional User user = 2;
+	google.protobuf.Any user = 2;
 	// Args specifies the binary and arguments for the application to
 	// execute.
 	repeated string args = 3;
 	// Env populates the process environment for the process.
 	repeated string env = 4;
 	// Cwd is the current working directory for the process and must be
 	// relative to the container's root.
-	optional string cwd = 5;
-}
-
-enum PlatformType {
-	UNKNOWN = 0;
-	LINUX = 1;
-}
-
-// User specifies user information for the process.
-message User {
-	// Type so that receivers of this message can `switch` for the fields
-	// expected
-	optional PlatformType type = 1;
-
-	//optional LinuxUser linux_type = 2;
-	extensions 100 to 499;
+	string cwd = 5;
 }
 
 // LinuxUser specifies linux specific user and group information for the
 // container's main process.
-extend User {
+message LinuxUser {
 	// Uid is the user id.
-	optional int32 uid = 101;
+	int32 uid = 101;
 	// Gid is the group id.
-	optional int32 gid = 102;
+	int32 gid = 102;
 	repeated int32 additional_gids = 103;
 }
 
 // Root contains information about the container's root filesystem on the host.
 message Root {
 	// Path is the absolute path to the container's root filesystem.
-	optional string path = 1;
+	string path = 1;
 	// Readonly makes the root filesystem for the container readonly before
 	// the process is executed.
-	optional bool readonly = 2;
+	bool readonly = 2;
 }
 
 // MountPoint describes a directory that may be fullfilled by a mount in the
 // runtime.json.
 message MountPoint {
 	// Name is a unique descriptive identifier for this mount point.
-	optional string name = 1;
+	string name = 1;
 	// Path specifies the path of the mount. The path and child directories
 	// MUST exist, a runtime MUST NOT create directories automatically to a
 	// mount point.
-	optional string path = 2;
+	string path = 2;
 }

proto/example.cc

@@ -0,0 +1,104 @@
+// See README.txt for information and build instructions.
+
+#include <fstream>
+#include <iostream>
+#include <string>
+
+#include <google/protobuf/descriptor.h>
+#include <google/protobuf/util/json_util.h>
+#include <google/protobuf/util/type_resolver.h>
+#include <google/protobuf/util/type_resolver_util.h>
+
+#include "config.pb.h"
+#include "runtime_config.pb.h"
+
+using namespace std;
+
+static const char kTypeUrlPrefix[] = "type.googleapis.com";
+
+static string GetTypeUrl(const google::protobuf::Descriptor* message) {
+  return string(kTypeUrlPrefix) + "/" + message->full_name();
+}
+
+static bool ReadMessage(string path, google::protobuf::Message *message) {
+  string binary;
+  ifstream input(path.c_str(), ios::in | ios::binary);
+  if (!input) {
+    cout << path << ": File not found." << endl;
+    return false;
+  }
+  string json( (istreambuf_iterator<char>(input)),
+               istreambuf_iterator<char>() );
+  google::protobuf::scoped_ptr<google::protobuf::util::TypeResolver> resolver;
+  resolver.reset(google::protobuf::util::NewTypeResolverForDescriptorPool(
+    kTypeUrlPrefix,
+    google::protobuf::DescriptorPool::generated_pool()));
+  GOOGLE_CHECK_OK(google::protobuf::util::JsonToBinaryString(
+    resolver.get(),
+    GetTypeUrl(message->GetDescriptor()),
+    json,
+    &binary));
+  return message->ParseFromString(binary);
+}
+
+static bool WriteMessage(const google::protobuf::Message& message) {
+  string json;
+  google::protobuf::util::JsonOptions options;
+  google::protobuf::scoped_ptr<google::protobuf::util::TypeResolver> resolver;
+  resolver.reset(google::protobuf::util::NewTypeResolverForDescriptorPool(
+    kTypeUrlPrefix,
+    google::protobuf::DescriptorPool::generated_pool()));
+  options.add_whitespace = true;
+  GOOGLE_CHECK_OK(google::protobuf::util::BinaryToJsonString(
+    resolver.get(),
+    GetTypeUrl(message.GetDescriptor()),
+    message.SerializeAsString(),
+    &json,
+    options));
+  cout << json;
+  return true;
+}
+
+// Main function: Reads the config from a file and writes it to stdout.
+int main(int argc, char* argv[]) {
+  // Verify that the version of the library that we linked against is
+  // compatible with the version of the headers we compiled against.
+  GOOGLE_PROTOBUF_VERIFY_VERSION;
+
+  oci::Spec config;
+  oci::RuntimeSpec runtime;
+
+  if (!ReadMessage("config.json", &config)) {
+    cerr << "config.json: Failed to load." << endl;
+    return -1;
+  }
+
+/*
+  oci::LinuxUser user;
+  user.set_uid(1);
+  user.set_gid(1);
+  user.add_additional_gids(5);
+  user.add_additional_gids(6);
+  config.mutable_process()->mutable_user()->PackFrom(user);
+*/
+
+  if (!WriteMessage(config)) {
+    cerr << "config.json: Failed to write to stdout." << endl;
+    return -1;
+  }
+
+  if (!ReadMessage("runtime.json", &runtime)) {
+    cerr << "runtime.json: Failed to load." << endl;
+    return -1;
+  }
+
+  if (!WriteMessage(runtime)) {
+    cerr << "runtime.json: Failed to write to stdout." << endl;
+    return -1;
+  }
+
+  // Optional:  Delete all global objects allocated by libprotobuf.
+  google::protobuf::ShutdownProtobufLibrary();
+
+  return 0;
+}