A little detail of go run

This is a creation in Article, where the information may have evolved or changed.

One of the advantages of Golang is that the compilation is fast and can be used as a scripting language, using go run to execute the. Go file directly, just like executing a script.

I like this very much, and I don't usually bother to build. However, when trying to Beego (Https://github.com/astaxie/beego) frame, just write a Hello world, always wrong, prompted to find the template.

Start a long debugging, look at the source code, modify the configuration 、、、 a variety of not.

2013/05/01 10:03:11 [C] [Handler crashed with error can ' t find templatefile in the PATH:INDEX.TPL]
2013/05/01 10:03:11 [C] [/build/buildd/golang-1/src/pkg/runtime/proc.c 1443]
2013/05/01 10:03:11 [C] [/usr/lib/go/src/pkg/github.com/astaxie/beego/controller.go 178]
2013/05/01 10:03:11 [C] [/usr/lib/go/src/pkg/github.com/astaxie/beego/controller.go]
2013/05/01 10:03:11 [C] [/usr/lib/go/src/pkg/reflect/value.go 521]
2013/05/01 10:03:11 [C] [/usr/lib/go/src/pkg/reflect/value.go 334]
2013/05/01 10:03:11 [C] [/usr/lib/go/src/pkg/github.com/astaxie/beego/router.go 375]
2013/05/01 10:03:11 [C] [/usr/lib/go/src/pkg/net/http/server.go 656]
2013/05/01 10:03:11 [C] [/build/buildd/golang-1/src/pkg/runtime/proc.c 271]

Then debug it:

Go Build Main.go

GdB./main

Run

It's all right.

Direct execution./main, it's OK.

Read the relevant code again, Beego find the configuration, template and other files are from the current execution directory to find relevant subdirectories.

Beego.go 48:apppath, _ = os. GETWD ()

Suspect that the execution path of Go run is not the current path.

Check out the Help for Go run:

Go help Run
Usage:go run [build flags] gofiles ... [Arguments ...]
Run compiles and runs the main package comprising the named Go source files.
For more on build flags, see ' Go help build '.
See Also:go build.

See this meaning, is automatically compiled + run ...

The first thing to suspect is that this path is not the path to which the Go tool is located.

Verify:

Go run./main.go

PS, hmm, where's a.out?

49391 PTS/1 00:00:00 Go
49399 PTS/1 00:00:00 a.out

Take a look at the details:

0 49391 42236 0 66416 5204 ffffff sl+ pts/1 0:00 go run./main.go
0 49399 49391 0 146000 4272 ffffff sl+ pts/1 0:00/tmp/go-build402905850/command-line-argument S/_obj/a.out

It is clear here that the Go Run command actually runs to the/tmp directory to create a/go-buildxxxx directory, compile and run.

This could bring up a minor problem,

1. If you depend on the relative path of the file, like above, there will be problems;

2. If executed continuously, new temporary files will be generated continuously.

So Golang should be careful when scripting.