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-- FAIL: TestGet (0.00s)
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x1 addr=0x0 pc=0x146263]

goroutine 5 [running]:
testing.func·006()
/Users/youngking/.gvm/gos/go1.4.2/src/testing/testing.go:441 +0x181
github.com/benschw/dns-clb-go/dns.(_LookupLib).lookup(0xc20800abb0, 0xc20801e0c0, 0x1a, 0x3d59b0, 0x3, 0x3df690, 0x3, 0xc20802a600, 0x0, 0x0)
/Users/youngking/gspace/src/github.com/benschw/dns-clb-go/dns/lib.go:107 +0x3d3
github.com/benschw/dns-clb-go/dns.(_LookupLib).lookup(0xc20800abb0, 0xc20801e0c0, 0x1a, 0x3d59b0, 0x3, 0x0, 0x0, 0x0, 0x0, 0x0)
/Users/youngking/gspace/src/github.com/benschw/dns-clb-go/dns/lib.go:104 +0x39b
github.com/benschw/dns-clb-go/dns.(_LookupLib).lookupType(0xc20800abb0, 0x4228f0, 0x19, 0x3d59b0, 0x3, 0x0, 0x0, 0x0)
/Users/youngking/gspace/src/github.com/benschw/dns-clb-go/dns/lib.go:85 +0x7c
github.com/benschw/dns-clb-go/dns.(_LookupLib).LookupSRV(0xc20800abb0, 0x4228f0, 0x19, 0x0, 0x0, 0x0, 0x0, 0x0)
/Users/youngking/gspace/src/github.com/benschw/dns-clb-go/dns/lib.go:43 +0xce
github.com/benschw/dns-clb-go/randomclb.(*RandomClb).GetAddress(0xc20800abc0, 0x4228f0, 0x19, 0x0, 0x0, 0x0, 0x0, 0x0)
/Users/youngking/gspace/src/github.com/benschw/dns-clb-go/randomclb/random.go:22 +0xbf

I really like this approach.

So, for dumb web apps, some extra things are needed.

Lets asume:

1. www.example.com boots off s3. done
2. api.example.com represents your client side load balancer services

to make this work a web sockets Or http long polling layer is needed to constantly update the web clients about what servers are up, with them ordered based on priority.

What do you think ?

RandomClb.GetAddress() panics when there are no SRV records found for the given name. RoundRobinClb guards against this, returning fmt.Errorf("no SRV records found"), but RandomClb gives:

panic: invalid argument to Intn

goroutine 16 [running]:
runtime.panic(0x5cf040, 0xc208000710)
        /usr/local/go/src/pkg/runtime/panic.c:279 +0xf5
math/rand.(*Rand).Intn(0xc208000160, 0x0, 0x0)
        /usr/local/go/src/pkg/math/rand/rand.go:95 +0x71
math/rand.Intn(0x0, 0x698577)
        /usr/local/go/src/pkg/math/rand/rand.go:195 +0x34
github.com/benschw/dns-clb-go/randomclb.(*RandomClb).GetAddress(0xc2080005a0, 0x698577, 0x17, 0x0, 0x0, 0x0, 0x0, 0x0)
        /home/sheldonh/go/src/github.com/benschw/dns-clb-go/randomclb/random.go:27 +0x126
main.main()
        /home/sheldonh/go/src/github.com/sheldonh/foo/foo.go:24 +0x36d