protoc 自定义插件出错，程序未找到或不可执行

Question

I am trying to build a custom protoc plugin to generate custom output from.proto files. I literally copied java file containing CodeGenerator from protoc custom plugin as a starting point and renamed it. I also followed executable and created.sh file. The content of my shell script is as follows.

I also add the PATH variable value and output of the plugin execution. Can someone point me where I am going wrong with this? The shell script runs fine separately executing the main method

Answer 1

If that is your entire example.sh , it won't work because it doesn't have a "hashbang" line identifying the script interpreter.

It should be something like:

#!/bin/bash
set -e
java cp ...

I think that's likely your problem because I tried running protoc and specifying an plug-in in the same way you did, and it worked as long as the plug-in was actually executable on its own.

Answer 2

how about using absolute path of example.sh? protoc working directory may not be current folder.

Answer 3

The protoc error messaging is a little cryptic here. You have 3 options for providing a plugin to protoc :

1. A plugin in your $PATH following the protoc-gen-$NAME format. This will be automatically picked up.
2. A plugin not conforming to the above naming convention, but available in your $PATH . This can be executed with the --plugin=$some-nonconventional-name .
3. A plugin not in your $PATH . This requires suppling an absolute path or relative path (from the current working directory) to the executable. This is executed with --plugin=proto-gen-$any-name-you-want=$path-to-executable

Expanding on 3 above. If you create a file example-plugin :

#!/bin/bash

echo "Example Plugin Running!"

You'll then want to make sure it's executable:

chmod +x ./example-plugin

We need an output directory, let's make one:

mdkir plugin-output

We need a .proto file. Find one and name it anything you like, like MyProto.proto

Let's pick an arbitrary name for this plugin. We can call it foo .

Then you'll execute it with protoc as follows:

protoc --plugin=protoc-gen-foo=$PATH_TO_EXAMPLE_PLUGIN --foo_output=./plugin-output  MyProto.proto 

You should see something like:

--foo_out: protoc-gen-foo: Plugin output is unparseable: Example Plugin Running!\n