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+/netdiscover

README.md

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+# Netdiscover
+[![](https://godoc.org/github.com/CyCoreSystems/netdiscover/discover?status.svg)](http://godoc.org/github.com/CyCoreSystems/netdiscover/discover)
+
+Netdiscover is a Golang-based tool and library by which network information can
+be discovered on various cloud platforms and bare metal installations.  The
+typical use case is, when running inside Kubernetes or a container, to discover
+the public IP and/or hostname of the node on which the container is running.
+This is commonly necessary to configure VoIP applications.
+
+## CLI tool
+
+In the root directory can be found a CLI tool which can be used to query network
+information.  There are two options:
+
+  * `-provider <name>`:  if a cloud provider is specified, that provider's
+    metadata services will be used to determine the network information.
+    Otherwise, a best-effort approach will be used.
+  * `-field <name>`: if a field is specified, only that particular network
+    detail will be returned.  Otherwise, a JSON object will be returned
+    containing all network information which was discovered.
+
+## Supported providers
+
+Currently, this tool supports three cloud providers:
+
+  * `aws`: Amazon Web Services
+  * `azure`: Microsoft Azure Cloud
+  * `gcp`: Google Cloud Platform
+
+I am happy to accept pull requests to implement more providers.
+
+## Supported Fields
+
+Currently, this tool supports four network data fields:
+
+  * `hostname`: the public hostname of the node
+  * `privatev4`: the private (internal) IPv4 address of the node
+  * `publicv4`: the public (external) IPv4 address of the node
+  * `publicv6`: the public (external) IPv6 address of the node
+
+
+## Examples
+
+Retrieve the public version 4 IP address of the node instance on GCP:
+
+```
+  netdiscover -provider gcp -field publicv4
+```
+
+Retrieve all network information on Amazon Wed Services platform:
+
+```
+  netdiscover -provider aws
+```
+
+Retrieve the version 6 IP address of a baremetal machine:
+
+```
+  netdiscover -field publicv6
+```
+

discover/aws.go

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+package discover
+
+import (
+	"net"
+)
+
+const (
+	awsPrivateIPv4URL = "http://169.254.169.254/latest/meta-data/local-ipv4"
+	awsPublicIPv4URL  = "http://169.254.169.254/latest/meta-data/public-ipv4"
+	awsHostnameURL    = "http://169.254.169.254/latest/meta-data/public-hostname"
+)
+
+// NewAWSDiscoverer returns a new Amazon Web Services network discoverer
+func NewAWSDiscoverer() Discoverer {
+	return NewDiscoverer(
+		PrivateIPv4DiscovererOption(awsPrivateIPv4),
+		PublicIPv4DiscovererOption(awsPublicIPv4),
+		PublicHostnameDiscovererOption(awsHostname),
+	)
+
+}
+
+func awsPrivateIPv4() (net.IP, error) {
+	return StandardIPFromHTTP(awsPrivateIPv4URL, nil)
+}
+
+func awsPublicIPv4() (net.IP, error) {
+	return StandardIPFromHTTP(awsPublicIPv4URL, nil)
+}
+
+func awsHostname() (string, error) {
+	return StandardHostnameFromHTTP(awsHostnameURL, nil)
+}

discover/azure.go

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+package discover
+
+import (
+	"net"
+)
+
+const (
+	azurePrivateIPv4URL = "http://169.254.169.254/metadata/instance/network/interface/0/ipv4/ipAddress/0/privateIpAddress?api-version=2017-08-01&format=text"
+	azurePublicIPv4URL  = "http://169.254.169.254/metadata/instance/network/interface/0/ipv4/ipAddress/0/publicIpAddress?api-version=2017-08-01&format=text"
+)
+
+// NewAzureDiscoverer returns a new Google Cloud Platform network discoverer
+func NewAzureDiscoverer() Discoverer {
+	return NewDiscoverer(
+		PrivateIPv4DiscovererOption(azurePrivateIPv4),
+		PublicIPv4DiscovererOption(azurePublicIPv4),
+	)
+}
+
+func azurePrivateIPv4() (net.IP, error) {
+	return StandardIPFromHTTP(azurePrivateIPv4URL, map[string]string{"Metadata": "true"})
+}
+
+func azurePublicIPv4() (net.IP, error) {
+	return StandardIPFromHTTP(azurePublicIPv4URL, map[string]string{"Metadata": "true"})
+}