From 9bd20331ef7ac281f26965683ddfc60432080b24 Mon Sep 17 00:00:00 2001 From: William Petit Date: Tue, 9 Oct 2018 14:05:38 +0200 Subject: [PATCH] Add service discovery helper Use MDNS-SD to discover ReachRS services on the local network --- emlid/discovery.go | 70 +++++++++++++++++++++++++++++++++++++++++ emlid/discovery_test.go | 29 +++++++++++++++++ emlid/option.go | 7 +++++ emlid/util_test.go | 8 +++++ go.mod | 5 +++ go.sum | 10 ++++++ 6 files changed, 129 insertions(+) create mode 100644 emlid/discovery.go create mode 100644 emlid/discovery_test.go create mode 100644 emlid/util_test.go diff --git a/emlid/discovery.go b/emlid/discovery.go new file mode 100644 index 0000000..fba711e --- /dev/null +++ b/emlid/discovery.go @@ -0,0 +1,70 @@ +package emlid + +import ( + "net" + "sync" + "time" + + "github.com/oleksandr/bonjour" +) + +// Service is a ReachRS service discovered via MDNS-SD +type Service struct { + Name string + AddrV4 net.IP + Port int +} + +// Discover tries to discover ReachRS services on the local network via MDNS-SD +func Discover(timeout time.Duration) ([]Service, error) { + + var wg sync.WaitGroup + + wg.Add(1) + + resolver, err := bonjour.NewResolver(nil) + if err != nil { + return nil, err + } + + services := make([]Service, 0) + entries := make(chan *bonjour.ServiceEntry) + timer := time.NewTimer(timeout) + defer timer.Stop() + + stop := func() { + resolver.Exit <- true + wg.Done() + } + + go func() { + for { + select { + + case e, ok := <-entries: + if !ok { + stop() + return + } + services = append(services, Service{ + Name: e.Instance, + AddrV4: e.AddrIPv4, + Port: e.Port, + }) + + case <-timer.C: + stop() + return + } + } + }() + + if err = resolver.Browse("_reach._tcp", ".local", entries); err != nil { + return nil, err + } + + wg.Wait() + + return services, nil + +} diff --git a/emlid/discovery_test.go b/emlid/discovery_test.go new file mode 100644 index 0000000..33fe64c --- /dev/null +++ b/emlid/discovery_test.go @@ -0,0 +1,29 @@ +package emlid + +import ( + "testing" + "time" +) + +func TestDiscovery(t *testing.T) { + + if !*runDiscoveryIntegrationTests { + t.Skip("To run this test, use: go test -discovery-integration") + } + + services, err := Discover(3 * time.Second) + if err != nil { + t.Fatal(err) + } + + if g, e := len(services), 1; g != e { + t.Fatalf("len(services): got '%d', expected '%d'", g, e) + } + + s := services[0] + + if g, e := s.Name, "reach"; g != e { + t.Errorf("services[0].Name: got '%s', expected '%s'", g, e) + } + +} diff --git a/emlid/option.go b/emlid/option.go index bb3db33..25d7f18 100644 --- a/emlid/option.go +++ b/emlid/option.go @@ -34,6 +34,13 @@ func WithEndpoint(host string, port int) OptionFunc { } } +// WithService configures the client to target the given ReachRS service +func WithService(service Service) OptionFunc { + return func(opts *Options) { + opts.Endpoint = gosocketio.GetUrl(service.AddrV4.String(), service.Port, false) + } +} + // WithPingInterval configures the client to use the given ping interval func WithPingInterval(interval time.Duration) OptionFunc { return func(opts *Options) { diff --git a/emlid/util_test.go b/emlid/util_test.go new file mode 100644 index 0000000..77a597c --- /dev/null +++ b/emlid/util_test.go @@ -0,0 +1,8 @@ +package emlid + +import "flag" + +var runDiscoveryIntegrationTests = flag.Bool( + "discovery-integration", false, + "Run the 'Discovery' integration tests (in addition to the unit tests)", +) diff --git a/go.mod b/go.mod index 066ee89..c1cbc6b 100644 --- a/go.mod +++ b/go.mod @@ -6,10 +6,15 @@ require ( github.com/davecgh/go-spew v1.1.1 // indirect github.com/go-chi/chi v3.3.3+incompatible github.com/gorilla/websocket v1.4.0 // indirect + github.com/miekg/dns v1.0.12 // indirect github.com/mitchellh/mapstructure v1.0.0 + github.com/oleksandr/bonjour v0.0.0-20160508152359-5dcf00d8b228 github.com/pkg/errors v0.8.0 github.com/pmezard/go-difflib v1.0.0 // indirect github.com/stretchr/testify v1.2.2 // indirect + golang.org/x/crypto v0.0.0-20181001203147-e3636079e1a4 // indirect golang.org/x/net v0.0.0-20180911220305-26e67e76b6c3 // indirect + golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f // indirect + golang.org/x/sys v0.0.0-20181005133103-4497e2df6f9e // indirect golang.org/x/text v0.3.0 // indirect ) diff --git a/go.sum b/go.sum index eb81ba4..70906a3 100644 --- a/go.sum +++ b/go.sum @@ -8,15 +8,25 @@ github.com/go-chi/chi v3.3.3+incompatible h1:KHkmBEMNkwKuK4FdQL7N2wOeB9jnIx7jR5w github.com/go-chi/chi v3.3.3+incompatible/go.mod h1:eB3wogJHnLi3x/kFX2A+IbTBlXxmMeXJVKy9tTv1XzQ= github.com/gorilla/websocket v1.4.0 h1:WDFjx/TMzVgy9VdMMQi2K2Emtwi2QcUQsztZ/zLaH/Q= github.com/gorilla/websocket v1.4.0/go.mod h1:E7qHFY5m1UJ88s3WnNqhKjPHQ0heANvMoAMk2YaljkQ= +github.com/miekg/dns v1.0.12 h1:814rTNaw7Q7pGncpSEDT06YS8rdGmpUEnKgpQzctJsk= +github.com/miekg/dns v1.0.12/go.mod h1:W1PPwlIAgtquWBMBEV9nkV9Cazfe8ScdGz/Lj7v3Nrg= github.com/mitchellh/mapstructure v1.0.0 h1:vVpGvMXJPqSDh2VYHF7gsfQj8Ncx+Xw5Y1KHeTRY+7I= github.com/mitchellh/mapstructure v1.0.0/go.mod h1:FVVH3fgwuzCH5S8UJGiWEs2h04kUh9fWfEaFds41c1Y= +github.com/oleksandr/bonjour v0.0.0-20160508152359-5dcf00d8b228 h1:Cvfd2dOlXIPTeEkOT/h8PyK4phBngOM4at9/jlgy7d4= +github.com/oleksandr/bonjour v0.0.0-20160508152359-5dcf00d8b228/go.mod h1:MGuVJ1+5TX1SCoO2Sx0eAnjpdRytYla2uC1YIZfkC9c= github.com/pkg/errors v0.8.0 h1:WdK/asTD0HN+q6hsWO3/vpuAkAr+tw6aNJNDFFf0+qw= github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0= github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM= github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4= github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w= github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs= +golang.org/x/crypto v0.0.0-20181001203147-e3636079e1a4 h1:Vk3wNqEZwyGyei9yq5ekj7frek2u7HUfffJ1/opblzc= +golang.org/x/crypto v0.0.0-20181001203147-e3636079e1a4/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4= golang.org/x/net v0.0.0-20180911220305-26e67e76b6c3 h1:czFLhve3vsQetD6JOJ8NZZvGQIXlnN3/yXxbT6/awxI= golang.org/x/net v0.0.0-20180911220305-26e67e76b6c3/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4= +golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f h1:wMNYb4v58l5UBM7MYRLPG6ZhfOqbKu7X5eyFl8ZhKvA= +golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM= +golang.org/x/sys v0.0.0-20181005133103-4497e2df6f9e h1:EfdBzeKbFSvOjoIqSZcfS8wp0FBLokGBEs9lz1OtSg0= +golang.org/x/sys v0.0.0-20181005133103-4497e2df6f9e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY= golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg= golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=