dbus.Store: length mismatch

[XiJinyu]

When I use this tool, it report the following error:

[root@localhost bin]# ./ganesha_exporter
2021/08/12 10:59:44 dbus.Store: length mismatch
panic: dbus.Store: length mismatch

goroutine 9 [running]:
log.Panic(0xc0002056c0, 0x1, 0x1)
/usr/lib/golang/src/log/log.go:351 +0xae
github.com/Gandi/ganesha_exporter/dbus.ExportMgr.GetNFSv41IO(0x9bc080, 0xc0000a2000, 0x2711, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
/root/go/pkg/mod/github.com/!gandi/[email protected]/dbus/export_mgr.go:105 +0x58a
main.ExportsCollector.Collect(0x9bc080, 0xc0000a2000, 0xc0000260c0, 0xc0000260c1, 0xc0000260c2, 0xc0000260c3, 0xc0000b0120)
/root/go/pkg/mod/github.com/!gandi/[email protected]/exportsCollector.go:282 +0x2e98
github.com/prometheus/client_golang/prometheus.DescribeByCollect.func1(0x9b6620, 0xc0000a2d50, 0xc0000b0120)
/root/go/pkg/mod/github.com/prometheus/[email protected]/prometheus/collector.go:90 +0x3b
created by github.com/prometheus/client_golang/prometheus.DescribeByCollect
/root/go/pkg/mod/github.com/prometheus/[email protected]/prometheus/collector.go:89 +0x75

[root@localhost bin]# ./ganesha_exporter --web.telemetry-path="/1m"
2021/08/12 11:07:02 dbus.Store: length mismatch
panic: dbus.Store: length mismatch

goroutine 38 [running]:
log.Panic(0xc0002896c0, 0x1, 0x1)
/usr/lib/golang/src/log/log.go:351 +0xae
github.com/Gandi/ganesha_exporter/dbus.ExportMgr.GetNFSv41IO(0x9bc080, 0xc000214000, 0x2711, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
/root/go/pkg/mod/github.com/!gandi/[email protected]/dbus/export_mgr.go:105 +0x58a
main.ExportsCollector.Collect(0x9bc080, 0xc000214000, 0xc000208008, 0xc000208009, 0xc00020800a, 0xc00020800b, 0xc000226120)
/root/go/pkg/mod/github.com/!gandi/[email protected]/exportsCollector.go:282 +0x2e98
github.com/prometheus/client_golang/prometheus.DescribeByCollect.func1(0x9b6620, 0xc000214d50, 0xc000226120)
/root/go/pkg/mod/github.com/prometheus/[email protected]/prometheus/collector.go:90 +0x3b
created by github.com/prometheus/client_golang/prometheus.DescribeByCollect
/root/go/pkg/mod/github.com/prometheus/[email protected]/prometheus/collector.go:89 +0x75

[root@localhost bin]# ./ganesha_exporter --collector.exports.nfsv3
2021/08/12 11:13:10 dbus.Store: length mismatch
panic: dbus.Store: length mismatch

goroutine 25 [running]:
log.Panic(0xc0000ef6c0, 0x1, 0x1)
/usr/lib/golang/src/log/log.go:351 +0xae
github.com/Gandi/ganesha_exporter/dbus.ExportMgr.GetNFSv41IO(0x9bc080, 0xc0000ab8f0, 0x2711, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
/root/go/pkg/mod/github.com/!gandi/[email protected]/dbus/export_mgr.go:105 +0x58a
main.ExportsCollector.Collect(0x9bc080, 0xc0000ab8f0, 0xc0000c0aa0, 0xc0000c0aa1, 0xc0000c0aa2, 0xc0000c0aa3, 0xc00009e300)
/root/go/pkg/mod/github.com/!gandi/[email protected]/exportsCollector.go:282 +0x2e98
github.com/prometheus/client_golang/prometheus.DescribeByCollect.func1(0x9b6620, 0xc0001d6660, 0xc00009e300)
/root/go/pkg/mod/github.com/prometheus/[email protected]/prometheus/collector.go:90 +0x3b
created by github.com/prometheus/client_golang/prometheus.DescribeByCollect
/root/go/pkg/mod/github.com/prometheus/[email protected]/prometheus/collector.go:89 +0x75

How to slove it ?

[hit1943]

in file export_mgr.go："ExportID" should be "uint16"，not "uint32", and all functions that use exportID as input param should also modified，because the ganesha dbus interface define export_id type for uint16

you can use this command to check dbus interface define:
dbus-send --system --type=method_call --print-reply --dest=org.ganesha.nfsd /org/ganesha/nfsd/ExportMgr org.freedesktop.DBus.Introspectable.Introspect
then you can see the params type define like this:

the input param exp_id's type is 'q'，which means uint16:

so if your ganesha has more than 256 exports，you may need to midify your ganesha dbus interface define