feat(backend): Support configuring connection keepalive parameters

[ulyssa]

This is a draft PR that adds support for creating and updating backends with the different keepalive parameters:

• keepalive_time, which is how long HTTP keepalive connections will be kept when they are idle; I've made the flag for this --http-ka-time to make it easier to differentiate with the --tcp-ka-* flags.
• tcp_keepalive_enable, which determines whether TCP keepalives are turned on on connections.
• tcp_keepalive_interval which determines how long to wait in between sending each TCP keepalive probe.
• tcp_keepalive_probes which determines up to how many probes to send before considering the connection dead.
• tcp_keepalive_time which determines how long to wait after sending the last data packet before starting to send TCP keepalive probes.

[ulyssa]

This will depend on pulling in fastly/go-fastly#537 once it has a tag we can put in go.mod.

[Integralist]

@kpfleming this PR requires a new go-fastly release that contains fastly/go-fastly#537

[kpfleming]

This will need tests added in backend_test.go as well.

[ulyssa]

I added tests in f1fda72, which helped me realized that I missed accounting for the new fields in describe/list, which I've now done in 62f5074.

[Integralist]

The build is failing...

Error: pkg/text/backend.go:41:7: b.TCPKeepAliveEnable undefined (type *fastly.Backend has no field or method TCPKeepAliveEnable)
Error: pkg/text/backend.go:44:68: b.TCPKeepAliveEnable undefined (type *fastly.Backend has no field or method TCPKeepAliveEnable)
Error: pkg/text/backend.go:46:68: b.TCPKeepAliveIntvl undefined (type *fastly.Backend has no field or method TCPKeepAliveIntvl)
Error: pkg/text/backend.go:47:66: b.TCPKeepAliveProbes undefined (type *fastly.Backend has no field or method TCPKeepAliveProbes)
Error: pkg/text/backend.go:48:67: b.TCPKeepAliveTime undefined (type *fastly.Backend has no field or method TCPKeepAliveTime)

[kpfleming]

The build is failing...

Error: pkg/text/backend.go:41:7: b.TCPKeepAliveEnable undefined (type *fastly.Backend has no field or method TCPKeepAliveEnable)
Error: pkg/text/backend.go:44:68: b.TCPKeepAliveEnable undefined (type *fastly.Backend has no field or method TCPKeepAliveEnable)
Error: pkg/text/backend.go:46:68: b.TCPKeepAliveIntvl undefined (type *fastly.Backend has no field or method TCPKeepAliveIntvl)
Error: pkg/text/backend.go:47:66: b.TCPKeepAliveProbes undefined (type *fastly.Backend has no field or method TCPKeepAliveProbes)
Error: pkg/text/backend.go:48:67: b.TCPKeepAliveTime undefined (type *fastly.Backend has no field or method TCPKeepAliveTime)

I haven't made a go-fastly release yet, so unless someone else did this will continue. That's on my agenda for today if nobody else does it first.

[kpfleming]

go-fastly 9.8.0 has been released.

[kpfleming]

Very very close :-)