feat(inputs.gnmi_listener): Add plugin

Author: srebhan

plugins/inputs/all/gnmi_listener.go

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+//go:build !custom || inputs || inputs.gnmi_listener
+
+package all
+
+import _ "github.com/influxdata/telegraf/plugins/inputs/gnmi_listener" // register plugin

plugins/inputs/gnmi_listener/README.md

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+# gNMI (gRPC Network Management Interface) dial-out Input Plugin
+
+This plugin consumes telemetry data based on [gNMI][gnmi] messages sent by
+network devices in dial-out mode. This plugin supports a list of vendor
+protocols such as [Nokia dial-out telemetry][nokia].
+
+⭐ Telegraf v1.39.0
+🏷️ network
+💻 all
+
+[gnmi]: https://github.com/openconfig/reference/blob/master/rpc/gnmi/gnmi-specification.md
+[nokia]: https://infocenter.nokia.com/public/7750SR222R1A/index.jsp?topic=%2Fcom.nokia.System_Mgmt_Guide%2Fdial-out_teleme-ai9exj5ye3.html
+
+## Service Input <!-- @/docs/includes/service_input.md -->
+
+This plugin is a service input. Normal plugins gather metrics determined by the
+interval setting. Service plugins start a service to listen and wait for
+metrics or events to occur. Service plugins have two key differences from
+normal plugins:
+
+1. The global or plugin specific `interval` setting may not apply
+2. The CLI options of `--test`, `--test-wait`, and `--once` may not produce
+   output for this plugin
+
+## Global configuration options <!-- @/docs/includes/plugin_config.md -->
+
+Plugins support additional global and plugin configuration settings for tasks
+such as modifying metrics, tags, and fields, creating aliases, and configuring
+plugin ordering. See [CONFIGURATION.md][CONFIGURATION.md] for more details.
+
+[CONFIGURATION.md]: ../../../docs/CONFIGURATION.md#plugins
+
+## Configuration
+
+```toml @sample.conf
+# gNMI dial-out telemetry plugin
+[[inputs.gnmi_listener]]
+  ## Address and port of the gNMI GRPC server
+  address = "localhost:57400"
+
+  ## Protocol to use, available options:
+  ##   nokia -- Nokia SR OS dial-out protocol
+  # protocol = "nokia"
+
+  ## Emit a metric for "delete" messages
+  # emit_delete_metrics = false
+
+  ## Enable to get the canonical path as field-name
+  # canonical_field_names = false
+
+  ## Remove leading slashes and dots in field-name
+  # trim_field_names = false
+
+  ## Prefix tags from path keys with the path element
+  # prefix_tag_key_with_path = false
+
+  ## Guess the path-tag if an update does not contain a prefix-path
+  ## Supported values are
+  ##   none         -- do not add a 'path' tag
+  ##   common path  -- use the common path elements of all fields in an update
+  ##   subscription -- use the subscription path
+  # path_guessing_strategy = "none"
+
+  ## Vendor specific options
+  ## This defines what vendor specific options to load.
+  ## * Juniper Header Extension (juniper_header): some sensors are directly managed by
+  ##   Linecard, which adds the Juniper GNMI Header Extension. Enabling this
+  ##   allows the decoding of the Extension header if present. Currently this knob
+  ##   adds component, component_id & sub_component_id as additional tags
+  # vendor_specific = []
+
+  ## YANG model paths for decoding IETF JSON payloads
+  ## Model files are loaded recursively from the given directories. Disabled if
+  ## no models are specified.
+  # yang_model_paths = []
+  ## Used for TLS server certificate authentication
+  # tls_cert = "/path/to/certfile"
+  ## Used for TLS server certificate authentication
+  # tls_key = "/path/to/keyfile"
+  ## Password for encrypted key files
+  # tls_key_pwd = ""
+  ## CA certificates used for verifying client certificates
+  # tls_allowed_cacerts = []
+  ## List of ciphers to accept, by default all secure ciphers will be accepted
+  ## See https://pkg.go.dev/crypto/tls#pkg-constants for supported values.
+  ## Use "all", "secure" and "insecure" to add all support ciphers, secure
+  ## suites or insecure suites respectively.
+  # tls_cipher_suites = ["secure"]
+  ## Minimal TLS version to accept by the server
+  # tls_min_version = "TLS12"
+  ## Maximum TLS version to accept by the server
+  # tls_max_version = ""
+  ## Whitelist for certificate DNS names to accept
+  # tls_allowed_dns_names = []
+```
+
+### Supported Nokia devices
+
+The `nokia` protocol supports Nokia SR OS devices with dial-out telemetry such
+as the following platforms:
+
+- 7250 Interconnect Router (IXR)
+- 7450 Ethernet Service Switch (ESS)
+- 7750 Service Router (SR)
+- 7950 Extensible Routing System (XRS)
+- Virtualized Service Router (VSR)
+
+See [server implementation](nokia/README.md) for details.
+
+## Metrics
+
+Each GNMI message will emit a different measurement. Leaf entries in a
+GNMI SubscribeResponse Update message will produce a field reading in the
+measurement. GNMI PathElement keys for leaves will attach tags to the field(s).
+
+## Example Output
+
+```text
+gnmi,path=openconfig-interfaces:/interfaces/interface/state/counters,host=linux,name=MgmtEth0/RP0/CPU0/0,source=10.49.234.115,descr/description=Foo in-multicast-pkts=0i,out-multicast-pkts=0i,out-errors=0i,out-discards=0i,in-broadcast-pkts=0i,out-broadcast-pkts=0i,in-discards=0i,in-unknown-protos=0i,in-errors=0i,out-unicast-pkts=0i,in-octets=0i,out-octets=0i,last-clear="2019-05-22T16:53:21Z",in-unicast-pkts=0i 1559145777425000000
+gnmi,path=openconfig-interfaces:/interfaces/interface/state/counters,host=linux,name=GigabitEthernet0/0/0/0,source=10.49.234.115,descr/description=Bar out-multicast-pkts=0i,out-broadcast-pkts=0i,in-errors=0i,out-errors=0i,in-discards=0i,out-octets=0i,in-unknown-protos=0i,in-unicast-pkts=0i,in-octets=0i,in-multicast-pkts=0i,in-broadcast-pkts=0i,last-clear="2019-05-22T16:54:50Z",out-unicast-pkts=0i,out-discards=0i 1559145777425000000
+```
+
+## Troubleshooting
+
+### Missing `path` tag
+
+Some devices (e.g. Arista) omit the prefix and specify the path in the update
+if there is only one value reported. This leads to a missing `path` tag for
+the resulting metrics. In those cases you should set `path_guessing_strategy`
+to `subscription` to use the subscription path as `path` tag.
+
+Other devices might omit the prefix in updates altogether. Here setting
+`path_guessing_strategy` to `common path` can help to infer the `path` tag by
+using the part of the path that is common to all values in the update.

plugins/inputs/gnmi_listener/gnmi_listener.go

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+//go:generate ../../../tools/config_includer/generator
+//go:generate ../../../tools/readme_config_includer/generator
+package gnmilistener
+
+import (
+	_ "embed"
+	"fmt"
+	"net"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+
+	"github.com/influxdata/telegraf"
+	common_gnmi "github.com/influxdata/telegraf/plugins/common/gnmi"
+	common_tls "github.com/influxdata/telegraf/plugins/common/tls"
+	"github.com/influxdata/telegraf/plugins/inputs"
+	"github.com/influxdata/telegraf/plugins/inputs/gnmi_listener/nokia"
+)
+
+//go:embed sample.conf
+var sampleConfig string
+
+type serverImplementation interface {
+	Register(*grpc.Server)
+}
+
+type GNMIListener struct {
+	Address  string          `toml:"address"`
+	Protocol string          `toml:"protocol"`
+	Log      telegraf.Logger `toml:"-"`
+	common_gnmi.HandlerConfig
+	common_tls.ServerConfig
+
+	options []grpc.ServerOption
+	server  *grpc.Server
+	handler *common_gnmi.Handler
+	addr    string
+}
+
+func (*GNMIListener) SampleConfig() string {
+	return sampleConfig
+}
+
+func (g *GNMIListener) Init() error {
+	// Defaults
+	if g.Address == "" {
+		g.Address = "localhost:57400"
+	}
+
+	// Check user settings
+	switch g.Protocol {
+	case "":
+		g.Protocol = "nokia"
+	case "nokia":
+		// Do nothing, those are valid
+	default:
+		return fmt.Errorf("invalid 'protocol' %q", g.Protocol)
+	}
+
+	// Fill the server options depending on the user settings
+	if tlsCfg, err := g.ServerConfig.TLSConfig(); err != nil {
+		return fmt.Errorf("creating TLS configuration failed: %w", err)
+	} else if tlsCfg != nil {
+		g.options = append(g.options, grpc.Creds(credentials.NewTLS(tlsCfg)))
+	}
+
+	if g.Log.Level().Includes(telegraf.Trace) {
+		g.options = append(g.options, grpc.InTapHandle(g.logCalls))
+	}
+
+	// Create a response handler
+	h, err := g.HandlerConfig.Handler(g.Log, common_gnmi.WithDefaultName("gnmi"))
+	if err != nil {
+		return fmt.Errorf("creating response handler failed: %w", err)
+	}
+	g.handler = h
+
+	return nil
+}
+
+func (g *GNMIListener) Start(acc telegraf.Accumulator) error {
+	// Create the protocol implementation
+	var impl serverImplementation
+	switch g.Protocol {
+	case "nokia":
+		impl = nokia.New(acc, g.handler, g.Log)
+	default:
+		return fmt.Errorf("invalid 'protocol' %q", g.Protocol)
+	}
+
+	// Create a listener or wrap it for debugging
+	listener, err := net.Listen("tcp", g.Address)
+	if err != nil {
+		return fmt.Errorf("listening on %q failed: %w", g.Address, err)
+	}
+	g.addr = listener.Addr().String()
+
+	// Start the server
+	g.server = grpc.NewServer(g.options...)
+	impl.Register(g.server)
+	go func() {
+		if err := g.server.Serve(listener); err != nil {
+			g.Log.Errorf("Stopping GRPC server on %q due to error: %v", g.addr, err)
+		}
+	}()
+
+	return nil
+}
+
+func (g *GNMIListener) Stop() {
+	if g.server != nil {
+		g.server.GracefulStop()
+	}
+}
+
+func (*GNMIListener) Gather(telegraf.Accumulator) error {
+	return nil
+}
+
+func init() {
+	inputs.Add("gnmi_listener", func() telegraf.Input {
+		return &GNMIListener{}
+	})
+}