Errors when building for Mac

[prasanthcaibmcom]

Can we cross compile a Mac build of our binary which uses go_ibm_db on a Linux machine?

When running with CGO_ENABLED=1:

+ CGO_ENABLED=1 GOOS=linux go build -a -installsuffix cgo -o agent-linux .
+ CGO_ENABLED=1 GOOS=windows go build -a -installsuffix cgo -o agent-windows .
+ CGO_ENABLED=1 GOOS=darwin go build -a -installsuffix cgo -o agent-darwin .
# net
../../tools/org.jenkinsci.plugins.golang.GolangInstallation/1.13/src/net/cgo_bsd.go:15:72: could not determine kind of name for C.AI_MASK
# os/user
../../tools/org.jenkinsci.plugins.golang.GolangInstallation/1.13/src/os/user/getgrouplist_darwin.go: In function ‘mygetgrouplist’:
../../tools/org.jenkinsci.plugins.golang.GolangInstallation/1.13/src/os/user/getgrouplist_darwin.go:16:11: warning: implicit declaration of function ‘getgrouplist’ [-Wimplicit-function-declaration]
  int rv = getgrouplist(user, (int) group, buf, ngroups);

Is it possible to cross-compile the package without building the driver into the binary? And allow the appropriate driver to be present at runtime ?

We are importing and using the driver like this:

import (
	"database/sql"

	_ "github.com/ibmdb/go_ibm_db"
)

	db, err := sql.Open("go_ibm_db", con)

We would like to use a single Linux environment to build all binaries for Windows, Mac, and Linux.

[akhilravuri1]

Hi @prasanthcaibmcom
Before Go 1.12 we can use binary-only packages but from Go1.12 binary-only packages are not supported.

You can cross-compile but our go driver needs clidriver of that platform(compilation) so if you have that platform clidriver you can use it.

Thanks,
Akhil

[prasanthcaibmcom]

Can we cross compile without CGO_ENABLED=1 as long the clidriver is present?

CGO_ENABLED=1 seems to cause the issue that I posted above for a Mac build. But I cannot seem to compile with CGO_ENABLED=0 either without error.

[akhilravuri1]

Our go driver is on top of the cli driver(which is written in c language) so you need to enable the CGO flag(CGO_ENABLED=1).

This may help you
https://medium.com/@diogok/on-golang-static-binaries-cross-compiling-and-plugins-1aed33499671

Thanks
Akhil

[prasanthcaibmcom]

I am trying to understand the nuance here about cross compiling:

Namely: Is there a way to not package the go_ibm_db2 driver building the go executable, so that we can build it without CGO_ENABLED ?

And then later, drop in the appropriate driver ?

[akhilravuri1]

Sorry!! you cannot use package go_ibm_db to an executable without enabling the CGO_ENABLED flag.

In the windows version, you can use it without the cgo_enabled flag.

Thanks,
Akhil

[prasanthcaibmcom]

Thanks. Closing this issue.

[prasanthcaibmcom]

I built the binary on a Mac system with CGO_ENABLED. When running on another Mac system, I get the following:

drsmac:~ macadmin$ ./drs-agent
dyld: Library not loaded: libdb2.dylib
Referenced from: /Users/macadmin/./drs-agent
Reason: image not found
Abort trap: 6

Does the cli driver always have to be bundled with the application using the driver?

This is with CGO_ENABLED=1 go build

[akhilravuri1]

I have never tested it. As of my knowledge no need to bundle the clidriver in the application. But the cli driver has to be present in the system where you are running the binary.

I will also give a try.

Thanks,
Akhil

[prasanthcaibmcom]

So this would mean packaging the clidriver folder that is generated by installer/setup.go for each platform?

[akhilravuri1]

Yes!!

dyld: Library not loaded: libdb2.dylib

This is error occurs when clidriver/lib is not found in the $DYLD_LIBRARY_PATH
It's not just packaging you need to set the env variables required.

[prasanthcaibmcom]

Ah, I see. Thanks !

[akhilravuri1]

Ah, I see. Thanks !

I will try to reproduce the issue..

Thanks,
Akhil

[prasanthcaibmcom]

@akhilravuri1 Is the go ibm driver supported on Linux ?