[receiver/wavefront] wrap metrics receiver under carbon receiver inst…

…ead of using export function (open-telemetry#27259)

**Description:** 
Wavefrontreceiver is very similar to carbonreceiver: it is TCP based in
which each received text line represents a single metric data point. In
order to avoid using exported function `carbonreceiver.New(...)`, we can
wrap metrics receiver under carbon receiver.

**Link to tracking Issue:** 

open-telemetry#27248

**Testing:** 
make chlog-validate
go test for wavefrontreceiver

**Documentation:**

---------

Co-authored-by: Pablo Baeyens <[email protected]>

.chloggen/fix-wavefront-metric-factory.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: 'enhancement'
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: wavefrontreceiver
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Wrap metrics receiver under carbon receiver instead of using export function
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [27248]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

receiver/wavefrontreceiver/factory.go

@@ -5,14 +5,13 @@ package wavefrontreceiver // import "github.com/open-telemetry/opentelemetry-col
 
 import (
  "context"
+ "fmt"
 
  "go.opentelemetry.io/collector/component"
  "go.opentelemetry.io/collector/config/confignet"
  "go.opentelemetry.io/collector/consumer"
  "go.opentelemetry.io/collector/receiver"
 
- "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/carbonreceiver"
- "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/carbonreceiver/protocol"
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/carbonreceiver/transport"
  "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/wavefrontreceiver/internal/metadata"
 )
@@ -42,27 +41,9 @@ func createMetricsReceiver(
  cfg component.Config,
  consumer consumer.Metrics,
 ) (receiver.Metrics, error) {
-
- rCfg := cfg.(*Config)
-
- // Wavefront is very similar to Carbon: it is TCP based in which each received
- // text line represents a single metric data point. They differ on the format
- // of their textual representation.
- //
- // The Wavefront receiver leverages the Carbon receiver code by implementing
- // a dedicated parser for its format.
- carbonCfg := carbonreceiver.Config{
- NetAddr: confignet.NetAddr{
- Endpoint: rCfg.Endpoint,
- Transport: "tcp",
- },
- TCPIdleTimeout: rCfg.TCPIdleTimeout,
- Parser: &protocol.Config{
- Type: "plaintext", // TODO: update after other parsers are implemented for Carbon receiver.
- Config: &WavefrontParser{
- ExtractCollectdTags: rCfg.ExtractCollectdTags,
- },
- },
+ rCfg, ok := cfg.(*Config)
+ if !ok {
+ return nil, fmt.Errorf("a wavefront receiver config was expected by the receiver factory, but got %T", rCfg)
  }
- return carbonreceiver.New(params, carbonCfg, consumer)
+ return newMetricsReceiver(rCfg, params, consumer), nil
 }

receiver/wavefrontreceiver/receiver.go

@@ -0,0 +1,72 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package wavefrontreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/wavefrontreceiver"
+
+import (
+ "context"
+
+ "go.opentelemetry.io/collector/component"
+ "go.opentelemetry.io/collector/config/confignet"
+ "go.opentelemetry.io/collector/consumer"
+ "go.opentelemetry.io/collector/receiver"
+
+ "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/carbonreceiver"
+ "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/carbonreceiver/protocol"
+)
+
+var _ receiver.Metrics = (*metricsReceiver)(nil)
+
+type metricsReceiver struct {
+ cfg *Config
+ set receiver.CreateSettings
+ nextConsumer consumer.Metrics
+ carbonReceiver receiver.Metrics
+}
+
+func newMetricsReceiver(cfg *Config, set receiver.CreateSettings, nextConsumer consumer.Metrics) *metricsReceiver {
+ return &metricsReceiver{
+ cfg: cfg,
+ set: set,
+ nextConsumer: nextConsumer,
+ }
+}
+
+func (r *metricsReceiver) Start(ctx context.Context, host component.Host) error {
+ fact := carbonreceiver.NewFactory()
+
+ // Wavefront is very similar to Carbon: it is TCP based in which each received
+ // text line represents a single metric data point. They differ on the format
+ // of their textual representation.
+ //
+ // The Wavefront receiver leverages the Carbon receiver code by implementing
+ // a dedicated parser for its format.
+ carbonCfg := &carbonreceiver.Config{
+ NetAddr: confignet.NetAddr{
+ Endpoint: r.cfg.Endpoint,
+ Transport: "tcp",
+ },
+ TCPIdleTimeout: r.cfg.TCPIdleTimeout,
+ Parser: &protocol.Config{
+ Type: "plaintext", // TODO: update after other parsers are implemented for Carbon receiver.
+ Config: &WavefrontParser{
+ ExtractCollectdTags: r.cfg.ExtractCollectdTags,
+ },
+ },
+ }
+
+ carbonReceiver, err := fact.CreateMetricsReceiver(ctx, r.set, carbonCfg, r.nextConsumer)
+ if err != nil {
+ return err
+ }
+ r.carbonReceiver = carbonReceiver
+
+ return r.carbonReceiver.Start(ctx, host)
+}
+
+func (r *metricsReceiver) Shutdown(ctx context.Context) error {
+ if r.carbonReceiver != nil {
+ return r.carbonReceiver.Shutdown(ctx)
+ }
+ return nil
+}