I have two protobuf files. I have to compare the contents of both of them in order to proceed further with the code. For this, i am trying to parse a protobuf file but some how i am not able to get the various message types and other information within the .proto file. I have to do all this in java.
Code snippets:
package com.example.demo;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import com.google.protobuf.DescriptorProtos;
import com.google.protobuf.DescriptorProtos.FileDescriptorProto;
import com.google.protobuf.Descriptors;
import com.google.protobuf.Descriptors.FileDescriptor;
import com.google.protobuf.InvalidProtocolBufferException;
public class TestProto {
public static FileDescriptorProto parseProto(InputStream protoStream)
throws InvalidProtocolBufferException, Descriptors.DescriptorValidationException {
DescriptorProtos.FileDescriptorProto descriptorProto = null;
try {
descriptorProto = FileDescriptorProto.parseFrom(protoStream);
} catch (IOException e) {
e.printStackTrace();
}
return descriptorProto;
}
public static InputStream readProto(File filePath) {
InputStream is = null;
Reader reader = null;
try {
is = new FileInputStream(filePath);
reader = new InputStreamReader(is);
int data = reader.read();
while (data != -1) {
System.out.print((char) data);
data = reader.read();
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return is;
}
public static void main(String args[]) {
InputStream protoStream = readProto(new File("D:/PROTOBUF CONVERTER/default.proto"));
Descriptors.FileDescriptor fileDescriptor = null;
DescriptorProtos.FileDescriptorProto fileDescriptorProto = null;
try {
fileDescriptorProto = parseProto(protoStream);
fileDescriptor = FileDescriptor.buildFrom(fileDescriptorProto, new FileDescriptor[] {}, true);
System.out.println("\n*******************");
System.out.println(fileDescriptor.getFullName());
System.out.println(fileDescriptor.getName());
System.out.println(fileDescriptor.getPackage());
System.out.println(fileDescriptor.getClass());
System.out.println(fileDescriptor.getDependencies());
System.out.println(fileDescriptor.toProto());
System.out.println(fileDescriptor.getServices());
System.out.println(fileDescriptor.getMessageTypes());
System.out.println(fileDescriptor.getOptions());
} catch(Exception e) {
e.printStackTrace();
}
}
}
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.springboot</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.xolstice.maven.plugins</groupId>
<artifactId>protobuf-maven-plugin</artifactId>
<version>0.6.1</version>
</dependency>
<dependency>
<groupId>com.google.protobuf</groupId>
<artifactId>protobuf-java</artifactId>
<version>3.5.1</version>
</dependency>
<!-- https://mvnrepository.com/artifact/commons-io/commons-io -->
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.6</version>
</dependency>
</dependencies>
<build>
<finalName>ProtobufParseDemo</finalName>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<inherited>true</inherited>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
default.proto
syntax = "proto3";
package tutorial;
option java_package = "com.example.tutorial";
option java_outer_classname = "AddressBookProtos";
message Person {
required string name = 1;
required int32 id = 2;
optional string email = 3;
enum PhoneType {
MOBILE = 0;
HOME = 1;
WORK = 2;
}
message PhoneNumber {
required string number = 1;
optional PhoneType type = 2 [default = HOME];
}
repeated PhoneNumber phones = 4;
}
message AddressBook {
repeated Person people = 1;
}
I can see the protofile data on the console due to code line "System.out.print((char) data);". However, i am not able to see any output in the sysout of the FileDescriptors. I am new to Protocol buffers.
Questions:
- what I am trying to do, is it relevant OR I am making some mistake?
- Is there any other method to do this in Java?
I have seen some answers, like the one here Protocol Buffers: How to parse a .proto file in Java. It says that the input to the parseFrom method should be of binary type i.e. a compiled schema. Is there a way in which we can obtain the compiled version of the .proto file in java code (not in command line)?
Ok, to be more clear on this, I have to compare two .proto files.
- First would be the one which is already uploaded with the ML model and
- Second would be the one which is to be uploaded for the same ML model.
If there are differences in the input or output message types of the two .proto files, then accordingly i have to increment the version number of the model.
I have found solutions where the proto is converted to proto descriptors and then converted to byte array and further passed tp parsrFrom method. Can't this process of converting .proto to proto.desc, be done via java code ?
Point to keep in mind here is that, i do not have the proto files in my classpath and giving the address in pom.xml (that of input and output directories) is not possible here as i have to download the old proto and compare it with the new proto to be uploaded as mentioned above.
