我想编译并运行go代码作为Postgresql存储过程。 我的动机是因为PostgreSQL可以用C语言编写golang excensions可以被编译为c-共享Golang过程语言Postgresql
所以我要文件,pl.go:
package main
/*
#cgo CFLAGS: -Wall -Wpointer-arith -Wno-declaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -fpic -I. -I./ -I/usr/include/postgresql/server -I/usr/include/postgresql/internal -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE -I/usr/include/libxml2
#cgo LDFLAGS: -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -fpic -L/usr/lib -Wl,-O1,--sort-common,--as-needed,-z,relro -Wl,--as-needed -Wl,-rpath,'/usr/lib',--enable-new-dtags -shared
#include "postgres.h"
#include "fmgr.h"
#include "utils/builtins.h"
#ifdef PG_MODULE_MAGIC
PG_MODULE_MAGIC;
#endif
//the return value must be allocated trough palloc
void* ret(void *val, uint64 *size) {
void *retDatum = palloc(*size);
memcpy(retDatum, val, *size);
return retDatum;
}
PG_FUNCTION_INFO_V1(plgo_func);
*/
import "C"
import "unsafe"
func main() {}
//PGVal returns the Postgresql C type from Golang type (currently implements just stringtotext)
func PGVal(val interface{}) (ret interface{}) {
var size uintptr
switch v := val.(type) {
case string:
ret = C.cstring_to_text(C.CString(v))
size = unsafe.Sizeof(ret)
default:
ret = val
size = unsafe.Sizeof(ret)
}
return C.ret(ret, (*C.uint64)(unsafe.Pointer(size)))
}
的CFLAGS
和LDFLAGS
i'we了从pg_config
,并在那里我创建函数来调用该文件,plgo.go:
package main
/*
#include "postgres.h"
#include "fmgr.h"
#include "utils/builtins.h"
*/
import "C"
//export plgo_func
func plgo_func(fcinfo *C.FunctionCallInfoData) interface{} {
return PGVal("meh")
}
共享库与创建:go build -buildmode=c-shared -o plgo.so plgo.go pl.go && sudo cp plgo.so /usr/lib/postgresql
PostgreSQL中的功能与创建:
CREATE OR REPLACE FUNCTION public.plgo_func(integer)
RETURNS text AS
'$libdir/plgo', 'plgo_func'
LANGUAGE c IMMUTABLE STRICT
COST 1;
但是当我运行:psql -U root -d meh -c "select plgo_func(0)"
服务器崩溃有:
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
connection to server was lost
编辑:我已经成功创建了golang“库”,用于在golang中创建存储过程和触发器plgo :)
C没有任何Go接口{}的概念。您需要从导出的函数中返回一个C类型。 (如果这不起作用,您需要从服务器获得更多调试信息,以了解它为什么崩溃) – JimB
这没有奏效,我该如何在该代码中添加一些调试/日志? '导入“日志”'而不是打印到文件不起作用... – microo8
我想你是'ret'函数中的segfaulting,因为'cstring_to_text'返回一个'* text',而你只有palloc该指针的大小,然后将'text'结构复制到该位置。我会首先在C语言中做一个概念验证,以确保在扩展到Go/cgo之前可以完成这个工作。 – JimB