Unset optional fields in config panics

[tdmanv]

Overview

According to https://github.com/IBM/ibmcloud-storage-volume-lib/blob/master/config/config.go#L35, all fields except for Server are optional.

When one of these optional fields is unset, GenerateContextCredentials will panic here: https://github.com/IBM/ibmcloud-storage-volume-lib/blob/master/provider/utils/init_provider.go#L141

Empty optional values are correctly handled elsewhere in the same file: https://github.com/IBM/ibmcloud-storage-volume-lib/blob/master/provider/utils/init_provider.go#L69

Repro

Any calls to GenerateContextCredentials with unset optional values will reproduce this issue.

Related Issues

• library is using panic intead of retuning error #33

• utils/init_provider.go stopped working #79

Example

We see this panic when using the kanister library and a nil VPC

[signal SIGSEGV: segmentation violation code=0x1 addr=0x40 pc=0x1474e32]
goroutine 11 [running]:
vendor/github.com/IBM/ibmcloud-storage-volume-lib/provider/utils.GenerateContextCredentials(0xc000b5d320, 0x277004b, 0xe, 0x2bfa2a0, 0xc000b9d0a0, 0xc0007ccb40, 0x0, 0x0, 0x0, 0x0, ...)
    /root/src/github.com/kastenhq/k10/go/src/vendor/github.com/IBM/ibmcloud-storage-volume-lib/provider/utils/init_provider.go:139 +0x232
vendor/github.com/IBM/ibmcloud-storage-volume-lib/provider/utils.OpenProviderSession(0xc000b5d320, 0x2bd7020, 0xc0009261b8, 0x277004b, 0xe, 0xc0007ccb40, 0x0, 0xc0010fef70, 0xc0010fefa0, 0x4a50d3, ...)
    /root/src/github.com/kastenhq/k10/go/src/vendor/github.com/IBM/ibmcloud-storage-volume-lib/provider/utils/init_provider.go:119 +0x358
vendor/github.com/kanisterio/kanister/pkg/blockstorage/ibm.newClient(0x2c0eda0, 0xc000058038, 0xc0010ff280, 0x0, 0x0, 0x0)
    /root/src/github.com/kastenhq/k10/go/src/vendor/github.com/kanisterio/kanister/pkg/blockstorage/ibm/client.go:100 +0x2ad
vendor/github.com/kanisterio/kanister/pkg/blockstorage/ibm.NewProvider(...)
    /root/src/github.com/kastenhq/k10/go/src/vendor/github.com/kanisterio/kanister/pkg/blockstorage/ibm/ibmcloud.go:57

[vkamra]

@pramodgavali - please take a look

[narkarum]

#173

[narkarum]

he above PR would resolve the issue.