开发环境：windows10，golang1.18.2，goland2022.2
最近在写项目时，一些数据类的结构以protobuf文件给定。因此，需要将这些protobuf文件转换为golang代码。
首先，在下载解析protobuf的包的时候就碰到了第一个问题...
go get -u github.com/golang/protobuf/protoc-gen-go
在我用上述命令后，终端提示该包已弃用
go: module github.com/golang/protobuf is deprecated: Use the "google.golang.org/protobuf" module instead.
随后直接用给出的新地址替换，这一次终端没有给出任何提示，但在GOPATH的bin目录下并没有出现想要的protoc-gen-go.exe文件。
故再次使用go install
go install google.golang.org/protobuf/cmd/protoc-gen-go@latest
成功安装上述可执行文件。
再次尝试解析.proto文件，报错：
'protoc-gen-go' 不是内部或外部命令，也不是可运行的程序或批处理文件。
又是因为没有将GOPATH\bin目录添加至环境变量中。。添加后测试终端输入：
$:protoc
Usage: D:\Application\protoc-21.7-win64\bin\protoc.exe [OPTION] PROTO_FILES
Parse PROTO_FILES and generate output based on the options given:
-IPATH, --proto_path=PATH Specify the directory in which to search for
imports. May be specified multiple times;
directories will be searched in order. If not
given, the current working directory is used.
If not found in any of the these directories,
the --descriptor_set_in descriptors will be
checked for required proto file.
--version Show version info and exit.
-h, --help Show this text and exit.
--encode=MESSAGE_TYPE Read a text-format message of the given type
from standard input and write it in binary
to standard output. The message type must
be defined in PROTO_FILES or their imports.
--deterministic_output When using --encode, ensure map fields are
deterministically ordered. Note that this order
is not canonical, and changes across builds or
releases of protoc.
--decode=MESSAGE_TYPE Read a binary message of the given type from
standard input and write it in text format
to standard output. The message type must
be defined in PROTO_FILES or their imports.
--decode_raw Read an arbitrary protocol message from
standard input and write the raw tag/value
pairs in text format to standard output. No
PROTO_FILES should be given when using this
flag.
--descriptor_set_in=FILES Specifies a delimited list of FILES
each containing a FileDescriptorSet (a
protocol buffer defined in descriptor.proto).
The FileDescriptor for each of the PROTO_FILES
provided will be loaded from these
FileDescriptorSets. If a FileDescriptor
appears multiple times, the first occurrence
will be used.
-oFILE, Writes a FileDescriptorSet (a protocol buffer,
--descriptor_set_out=FILE defined in descriptor.proto) containing all of
the input files to FILE.
--include_imports When using --descriptor_set_out, also include
all dependencies of the input files in the
set, so that the set is self-contained.
--include_source_info When using --descriptor_set_out, do not strip
SourceCodeInfo from the FileDescriptorProto.
This results in vastly larger descriptors that
include information about the original
location of each decl in the source file as
well as surrounding comments.
--dependency_out=FILE Write a dependency output file in the format
expected by make. This writes the transitive
set of input file paths to FILE
--error_format=FORMAT Set the format in which to print errors.
FORMAT may be 'gcc' (the default) or 'msvs'
(Microsoft Visual Studio format).
--fatal_warnings Make warnings be fatal (similar to -Werr in
gcc). This flag will make protoc return
with a non-zero exit code if any warnings
are generated.
--print_free_field_numbers Print the free field numbers of the messages
defined in the given proto files. Groups share
the same field number space with the parent
message. Extension ranges are counted as
occupied fields numbers.
--plugin=EXECUTABLE Specifies a plugin executable to use.
Normally, protoc searches the PATH for
plugins, but you may specify additional
executables not in the path using this flag.
Additionally, EXECUTABLE may be of the form
NAME=PATH, in which case the given plugin name
is mapped to the given executable even if
the executable's own name differs.
--cpp_out=OUT_DIR Generate C++ header and source.
--csharp_out=OUT_DIR Generate C# source file.
--java_out=OUT_DIR Generate Java source file.
--kotlin_out=OUT_DIR Generate Kotlin file.
--objc_out=OUT_DIR Generate Objective-C header and source.
--php_out=OUT_DIR Generate PHP source file.
--pyi_out=OUT_DIR Generate python pyi stub.
--python_out=OUT_DIR Generate Python source file.
@ Read options and filenames from file. If a
this argument file is searched. Content of
the file will be expanded in the position of
@ as in the argument list. Note
that shell expansion is not applied to the
content of the file (i.e., you cannot use
quotes, wildcards, escapes, commands, etc.).
Each line corresponds to a single argument,
even if it contains spaces.
已经成功完成proto工具的安装。
紧接着，再一次尝试——
提示无法确定生成go文件的路径
protoc --go_out=. test.proto
报错信息：
protoc-gen-go: unable to determine Go import path for "test.proto"
Please specify either:
• a "go_package" option in the .proto source file, or
• a "M" argument on the command line.
test.proto文件
如下：
syntax="proto3"; //版本号
package main; //包名
enum ClassName{ //枚举
class1=0; //标号 必须从 0开始
class2=1;
class3=2;
}
message Student{ //消息，对应于Go的结构体
string name=1; //1:标号，唯一 即可（相当于数据库中的Id，不一定要从1 ，2的顺序依次排列。）
int32 age=2; //必须指定整型的范围，如int32，int64
string address=3;
ClassName cn=4;
}
message Students{
repeated Student person=1; // repeated 修饰，相当于Go中切片
string school=2;
}
- protoc-gen-go v1.27.1
- protoc v3.12.3
原因是protoc-gen-go版本过高，对源proto文件需要添加包名。
还有一种解决办法就是把protoc-gen-go版本退回到1.3.2及以下也可以解决。
最终！！根据报错信息在文件中第二行后添加：（指定生成go文件的路径）
option go_package="/main"; //解决报错:unable to determine Go import path
总算成功在该目录下生成了test.pb.go文件！！！
总结
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