49 lines
1.5 KiB
Go
49 lines
1.5 KiB
Go
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// Copyright (C) 2020 Storj Labs, Inc.
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// See LICENSE for copying information.
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package rpc
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import (
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"context"
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"net"
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)
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// LookupNodeAddress resolves a storage node address to the first IP address resolved.
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// If an IP address is accidentally provided it is returned back. This function
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// is used to resolve storage node IP addresses so that uplinks can use
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// IP addresses directly without resolving many hosts.
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func LookupNodeAddress(ctx context.Context, nodeAddress string) string {
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host, port, err := net.SplitHostPort(nodeAddress)
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if err != nil {
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// If there was an error parsing out the port we just use a plain host.
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host = nodeAddress
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port = ""
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}
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// We check if the address is an IP address to decide if we need to resolve it or not.
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ip := net.ParseIP(host)
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// nodeAddress is already an IP, so we can use that.
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if ip != nil {
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return nodeAddress
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}
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// We have a hostname not an IP address so we should resolve the IP address
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// to give back to the uplink client.
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addresses, err := net.DefaultResolver.LookupHost(ctx, host)
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if err != nil || len(addresses) == 0 {
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// We ignore the error because if this fails for some reason we can just
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// re-use the hostname, it just won't be as fast for the uplink to dial.
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return nodeAddress
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}
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// We return the first address found because some DNS servers already do
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// round robin load balancing and we would be messing with their behaviour
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// if we tried to get smart here.
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first := addresses[0]
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if port == "" {
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return first
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}
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return net.JoinHostPort(first, port)
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}
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