fix: Update gopcua library to latest version

[srebhan]

• Updated associated README.md.
• Wrote appropriate unit tests.

resolves #9551

Update to the latest state of the gopcua library in the hope to fix potential timeout problems (see #9551).

[helenosheaa]

lgtm, thanks!

[sspaink]

Removing the ready for final review label because the issue reporter ran into a different issue after using the latest version. Needs more investigation.

[jnangle]

Hi @srebhan,

This code (v1.20.0 3) failed at the 1-hr mark with the following messages:

2021-08-03T16:00:07Z D! [outputs.influxdb_v2] Buffer fullness: 0 / 10000 metrics
2021-08-03T16:00:16Z E! [inputs.opcua] Error in plugin: RegisterNodes Read failed: The operation could not complete because the client is not connected to the server. StatusBadServerNotConnected (0x800D0000)
panic: close of closed channel
        panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xc0000005 code=0x0 addr=0x8 pc=0x32915ad]

goroutine 7715 [running]:
github.com/gopcua/opcua/uacp.(*Conn).Close(0x0, 0x0, 0x0)
        /go/pkg/mod/github.com/gopcua/opcua@v0.2.0-rc2.0.20210409063412-baabb9b14fd2/uacp/conn.go:166 +0x2d
panic(0x5138100, 0x62858b0)
        /usr/local/go/src/runtime/panic.go:965 +0x1c7
github.com/gopcua/opcua.(*Client).Close(0xc000ec61c0, 0x0, 0x0)
        /go/pkg/mod/github.com/gopcua/opcua@v0.2.0-rc2.0.20210409063412-baabb9b14fd2/client.go:516 +0xe9
github.com/influxdata/telegraf/plugins/inputs/opcua.Connect(0xc00016c340, 0x0, 0x0)
        /go/src/github.com/influxdata/telegraf/plugins/inputs/opcua/opcua_client.go:409 +0x52e
github.com/influxdata/telegraf/plugins/inputs/opcua.(*OpcUA).Gather(0xc00016c340, 0x6414658, 0xc000a3a240, 0xdb5b55, 0xc001387020)
        /go/src/github.com/influxdata/telegraf/plugins/inputs/opcua/opcua_client.go:522 +0x5c5
github.com/influxdata/telegraf/models.(*RunningInput).Gather(0xc00013c690, 0x6414658, 0xc000a3a240, 0xdf661d, 0x5cc0b80)
        /go/src/github.com/influxdata/telegraf/models/running_input.go:117 +0x74
github.com/influxdata/telegraf/agent.(*Agent).gatherOnce.func1(0xc000750de0, 0xc00013c690, 0x6414658, 0xc000a3a240)
        /go/src/github.com/influxdata/telegraf/agent/agent.go:469 +0x46
created by github.com/influxdata/telegraf/agent.(*Agent).gatherOnce
        /go/src/github.com/influxdata/telegraf/agent/agent.go:468 +0xc5

C:\Users\scada_read\Desktop\Installers\InfluxDB\telegraf-1.20.0 3>```

[sspaink]

In hindsight, probably would have been fine to merge this because we will need to update the library anyway.

@srebhan thanks for working on this, when you get the chance to resolve the merge conflicts I think this is ready to merge.

[srebhan]

@sspaink rebase done.

[telegraf-tiger]

Looks like new artifacts were built from this PR. Get them here!

Artifact URLs

• darwin_amd64.tar.gz

• armel.rpm

• linux_armel.tar.gz

• armel.deb

• static_linux_amd64.tar.gz

• s390x.rpm

• linux_s390x.tar.gz

• s390x.deb

• x86_64.rpm

• freebsd_amd64.tar.gz

• linux_amd64.tar.gz

• amd64.deb

• armv6hl.rpm

• freebsd_armv7.tar.gz

• linux_armhf.tar.gz

• armhf.deb

• aarch64.rpm

• linux_arm64.tar.gz

• arm64.deb

• i386.rpm

• freebsd_i386.tar.gz

• linux_i386.tar.gz

• i386.deb

• linux_mips.tar.gz

• mips.deb

• ppc64le.rpm

• linux_ppc64le.tar.gz

• ppc64el.deb

• linux_mipsel.tar.gz

• mipsel.deb

• windows_amd64.zip

• windows_i386.zip

[jnangle]

I ran the latest artifact (windows_amd64), configured to connect to a Red Lion OPC UA server using numeric ids tags and received this error:

D:\InfluxDB\telegraf-1.20.0 5>telegraf --config http://localhost:8086/api/v2/telegrafs/07d830630e2b0000  --test
2021-09-14T17:44:50Z I! Starting Telegraf
2021-09-14T17:44:50Z D! [agent] Initializing plugins
2021-09-14T17:44:50Z I! Failed to load certificate: open /etc/telegraf/cert.pem: The system cannot find the path specified.
2021-09-14T17:44:50Z D! [agent] Starting service inputs
2021-09-14T17:44:50Z E! [inputs.opcua] Error in plugin: registerNodes failed: EOF
2021-09-14T17:44:50Z D! [agent] Stopping service inputs
2021-09-14T17:44:50Z D! [agent] Input channel closed
2021-09-14T17:44:50Z D! [agent] Stopped Successfully
2021-09-14T17:44:50Z E! [telegraf] Error running agent: input plugins recorded 1 errors

The code works fine connecting to OPC UA servers that use strings for tag ids.