Add pipeline ID to the error message for unused connectors. (#12410)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description
As mentioned in this
#8721 (comment),
the error message for unused connectors currently lacks specific
pipeline names, making debugging more difficult.

This PR enhances the error message by including pipeline names in the
`[signal/name]` format, consistent with how they appear in
`config.yaml`. This provides a better context for identifying
misconfigurations.

<!-- Issue number if applicable -->
#### Link to tracking issue
Related to #8721 

<!--Describe what testing was performed and which tests were added.-->
#### Testing
A few scenarios and example output are given below. I will do additional
testing and add unit tests if necessary.

**1. Used as a receiver but not used as an exporter with 1 signal**
<details>
  <summary><strong>config.yaml</strong></summary>

```yaml
receivers:
  otlp:
    protocols:
      grpc:
exporters:
  debug:
connectors:
  forward:
service:
  pipelines:
    logs/in:
      receivers: [otlp]
      processors: []
      exporters: [debug]
    logs/out:
      receivers: [forward]
      processors: []
      exporters: [debug]
```
</details>

Main Branch Output:
```
Error: failed to build pipelines: connector "forward" used as receiver in logs pipeline but not used in any supported exporter pipeline
```
Proposed Output:
```
Error: failed to build pipelines: connector "forward" used as receiver in [logs/out] pipeline but not used in any supported exporter pipeline
```

**2. Plain**
<details>
  <summary><strong>config.yaml</strong></summary>

```yaml
receivers:
  otlp:
    protocols:
      grpc:
exporters:
  debug:
connectors:
  forward:
service:
  pipelines:
    traces:
      receivers: [ otlp ]
      processors: [ ]
      exporters: [ forward ]
    metrics:
      receivers: [ forward ]
      processors: [ ]
      exporters: [ debug ]
```
</details>

Main Branch Output:
```
Error: failed to build pipelines: connector "forward" used as exporter in traces pipeline but not used in any supported receiver pipeline
```
Proposed Output:
```
Error: failed to build pipelines: connector "forward" used as exporter in [traces] pipeline but not used in any supported receiver pipeline
```
**3. Multiple pipeline**
<details>
  <summary><strong>config.yaml</strong></summary>

```yaml
receivers:
  otlp:
    protocols:
      grpc:
exporters:
  debug:
connectors:
  forward:
service:
  pipelines:
    logs/in:
      receivers: [otlp]
      processors: []
      exporters: [forward]
    logs/in2:
      receivers: [ otlp ]
      processors: [ ]
      exporters: [ forward ]
    logs/out:
      receivers: [otlp]
      processors: []
      exporters: [debug]
    traces:
      receivers: [ otlp ]
      processors: [ ]
      exporters: [ forward ]
    metrics:
      receivers: [ forward ]
      processors: [ ]
      exporters: [ debug ]
```
</details>

Main Branch Output:
```
Error: failed to build pipelines: connector "forward" used as exporter in logs pipeline but not used in any supported receiver pipeline
```
Proposed Output:
```
Error: failed to build pipelines: connector "forward" used as exporter in [logs/in2 logs/in] pipeline but not used in any supported receiver pipeline

```

---------

Co-authored-by: Bogdan Drutu <[email protected]>

Author: sudiptob2

.chloggen/add-pipeline-names-with-signal-in-logs.yaml

@@ -0,0 +1,25 @@
+# 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. otlpreceiver)
+component:  pipeline
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "output pipeline name with signal as signal[/name] format in logs."
+
+# One or more tracking issues or pull requests related to the change
+issues: [12410]
+
+# (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:
+
+# 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: [user]

service/internal/graph/graph.go

@@ -171,13 +171,13 @@ func (g *Graph) createNodes(set Settings) error {
 			if supportedUse {
 				continue
 			}
-			return fmt.Errorf("connector %q used as exporter in %s pipeline but not used in any supported receiver pipeline", connID, expType)
+			return fmt.Errorf("connector %q used as exporter in %v pipeline but not used in any supported receiver pipeline", connID, formatPipelineNamesWithSignal(connectorsAsExporter[connID], expType))
 		}
 		for recType, supportedUse := range recTypes {
 			if supportedUse {
 				continue
 			}
-			return fmt.Errorf("connector %q used as receiver in %s pipeline but not used in any supported exporter pipeline", connID, recType)
+			return fmt.Errorf("connector %q used as receiver in %v pipeline but not used in any supported exporter pipeline", connID, formatPipelineNamesWithSignal(connectorsAsReceiver[connID], recType))
 		}
 
 		for _, eID := range connectorsAsExporter[connID] {
@@ -196,6 +196,17 @@ func (g *Graph) createNodes(set Settings) error {
 	return nil
 }
 
+// formatPipelineNamesWithSignal formats pipeline name with signal as "signal[/name]" format.
+func formatPipelineNamesWithSignal(pipelineIDs []pipeline.ID, signal pipeline.Signal) []string {
+	var formatted []string
+	for _, pid := range pipelineIDs {
+		if pid.Signal() == signal {
+			formatted = append(formatted, pid.String())
+		}
+	}
+	return formatted
+}
+
 func (g *Graph) createReceiver(pipelineID pipeline.ID, recvID component.ID) *receiverNode {
 	rcvrNode := newReceiverNode(pipelineID.Signal(), recvID)
 	if node := g.componentGraph.Node(rcvrNode.ID()); node != nil {

service/internal/graph/graph_test.go

@@ -1649,7 +1649,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in traces pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [traces/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_traces_metrics.yaml",
@@ -1672,7 +1672,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in traces pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [traces/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_traces_logs.yaml",
@@ -1695,7 +1695,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in traces pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [traces/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_traces_profiles.yaml",
@@ -1718,7 +1718,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in traces pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [traces/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_metrics_traces.yaml",
@@ -1741,7 +1741,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in metrics pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [metrics/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_metrics_metrics.yaml",
@@ -1764,7 +1764,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in metrics pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [metrics/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_metrics_logs.yaml",
@@ -1787,7 +1787,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in metrics pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [metrics/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_metrics_profiles.yaml",
@@ -1810,7 +1810,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in metrics pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [metrics/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_logs_traces.yaml",
@@ -1833,7 +1833,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in logs pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [logs/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_logs_metrics.yaml",
@@ -1856,7 +1856,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in logs pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [logs/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_logs_logs.yaml",
@@ -1879,7 +1879,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in logs pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [logs/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_logs_profiles.yaml",
@@ -1902,7 +1902,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in logs pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [logs/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_profiles_traces.yaml",
@@ -1925,7 +1925,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in profiles pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [profiles/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_profiles_metrics.yaml",
@@ -1948,7 +1948,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in profiles pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [profiles/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_profiles_logs.yaml",
@@ -1971,7 +1971,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in profiles pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [profiles/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "not_supported_connector_profiles_profiles.yaml",
@@ -1994,7 +1994,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: "connector \"bf\" used as exporter in profiles pipeline but not used in any supported receiver pipeline",
+			expected: "connector \"bf\" used as exporter in [profiles/in] pipeline but not used in any supported receiver pipeline",
 		},
 		{
 			name: "orphaned-connector-use-as-exporter",
@@ -2013,7 +2013,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewIDWithName("nop", "conn")},
 				},
 			},
-			expected: `connector "nop/conn" used as exporter in metrics pipeline but not used in any supported receiver pipeline`,
+			expected: `connector "nop/conn" used as exporter in [metrics/in] pipeline but not used in any supported receiver pipeline`,
 		},
 		{
 			name: "orphaned-connector-use-as-receiver",
@@ -2032,7 +2032,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: `connector "nop/conn" used as receiver in traces pipeline but not used in any supported exporter pipeline`,
+			expected: `connector "nop/conn" used as receiver in [traces/out] pipeline but not used in any supported exporter pipeline`,
 		},
 		{
 			name: "partially-orphaned-connector-use-as-exporter",
@@ -2059,7 +2059,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("mockforward")},
 				},
 			},
-			expected: `connector "mockforward" used as exporter in metrics pipeline but not used in any supported receiver pipeline`,
+			expected: `connector "mockforward" used as exporter in [metrics/in] pipeline but not used in any supported receiver pipeline`,
 		},
 		{
 			name: "partially-orphaned-connector-use-as-receiver",
@@ -2086,7 +2086,7 @@ func TestGraphBuildErrors(t *testing.T) {
 					Exporters: []component.ID{component.MustNewID("nop")},
 				},
 			},
-			expected: `connector "mockforward" used as receiver in traces pipeline but not used in any supported exporter pipeline`,
+			expected: `connector "mockforward" used as receiver in [traces/out] pipeline but not used in any supported exporter pipeline`,
 		},
 		{
 			name: "not_allowed_simple_cycle_traces.yaml",