[processor/attributes] validate metrics configuration parameters before processing (#37435)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description

Add validation for metrics-only configuration parameters

<!-- Issue number (e.g. #1234) or full URL to issue, if applicable. -->
#### Link to tracking issue
Fixes #36077

---------

Signed-off-by: odubajDT <[email protected]>

Author: odubajDT

Diff for: .chloggen/fix-metric-validation.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: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: attributesprocessor
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "Validate metrics configuration parameters before processing"
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [36077]
+
+# (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: []

Diff for: internal/filter/filterconfig/config.go

@@ -126,9 +126,11 @@ type MatchProperties struct {
 }
 
 var (
-	ErrMissingRequiredField    = errors.New(`at least one of "attributes", "libraries",  or "resources" field must be specified`)
-	ErrInvalidLogField         = errors.New("services, span_names, and span_kinds are not valid for log records")
-	ErrMissingRequiredLogField = errors.New(`at least one of "attributes", "libraries", "span_kinds", "resources", "log_bodies", "log_severity_texts" or "log_severity_number" field must be specified`)
+	ErrMissingRequiredSpanField   = errors.New(`at least one of "attributes", "libraries",  or "resources" field must be specified`)
+	ErrInvalidLogField            = errors.New("services, span_names, span_kinds and metric_names are not valid for log records")
+	ErrMissingRequiredLogField    = errors.New(`at least one of "attributes", "libraries", "span_kinds", "resources", "log_bodies", "log_severity_texts" or "log_severity_number" field must be specified`)
+	ErrMissingRequiredMetricField = errors.New(`at least one of "metric_names" or "resources" field must be specified`)
+	ErrInvalidMetricField         = errors.New(`"span_names", "span_kinds", "log_bodies", "log_severity_texts", "log_severity_number", "services", "attributes" and "libraries" are not valid for metrics`)
 
 	spanKinds = map[string]bool{
 		traceutil.SpanKindStr(ptrace.SpanKindInternal): true,
@@ -153,9 +155,13 @@ func (mp *MatchProperties) ValidateForSpans() error {
 		return errors.New("log_severity_number should not be specified for trace spans")
 	}
 
+	if len(mp.MetricNames) > 0 {
+		return errors.New("metric_names should not be specified for trace spans")
+	}
+
 	if len(mp.Services) == 0 && len(mp.SpanNames) == 0 && len(mp.Attributes) == 0 &&
 		len(mp.Libraries) == 0 && len(mp.Resources) == 0 && len(mp.SpanKinds) == 0 {
-		return ErrMissingRequiredField
+		return ErrMissingRequiredSpanField
 	}
 
 	if len(mp.SpanKinds) > 0 && mp.MatchType == "strict" {
@@ -176,7 +182,7 @@ func (mp *MatchProperties) ValidateForSpans() error {
 
 // ValidateForLogs validates properties for logs.
 func (mp *MatchProperties) ValidateForLogs() error {
-	if len(mp.SpanNames) > 0 || len(mp.Services) > 0 || len(mp.SpanKinds) > 0 {
+	if len(mp.SpanNames) > 0 || len(mp.Services) > 0 || len(mp.SpanKinds) > 0 || len(mp.MetricNames) > 0 {
 		return ErrInvalidLogField
 	}
 
@@ -190,6 +196,26 @@ func (mp *MatchProperties) ValidateForLogs() error {
 	return nil
 }
 
+// ValidateForMetrics validates properties for metrics.
+func (mp *MatchProperties) ValidateForMetrics() error {
+	if len(mp.LogBodies) > 0 ||
+		len(mp.LogSeverityTexts) > 0 ||
+		len(mp.SpanNames) > 0 ||
+		len(mp.Services) > 0 ||
+		len(mp.SpanKinds) > 0 ||
+		len(mp.Attributes) > 0 ||
+		len(mp.Libraries) > 0 ||
+		mp.LogSeverityNumber != nil {
+		return ErrInvalidMetricField
+	}
+
+	if len(mp.MetricNames) == 0 && len(mp.Resources) == 0 {
+		return ErrMissingRequiredMetricField
+	}
+
+	return nil
+}
+
 // Attribute specifies the attribute key and optional value to match against.
 type Attribute struct {
 	// Key specifies the attribute key.
@@ -261,15 +287,19 @@ type MetricMatchProperties struct {
 	ResourceAttributes []Attribute `mapstructure:"resource_attributes"`
 }
 
-func CreateMetricMatchPropertiesFromDefault(properties *MatchProperties) *MetricMatchProperties {
+func CreateMetricMatchPropertiesFromDefault(properties *MatchProperties) (*MetricMatchProperties, error) {
 	if properties == nil {
-		return nil
+		return nil, nil
+	}
+
+	if err := properties.ValidateForMetrics(); err != nil {
+		return nil, err
 	}
 
 	return &MetricMatchProperties{
 		MatchType:          MetricMatchType(properties.Config.MatchType),
 		RegexpConfig:       properties.Config.RegexpConfig,
 		MetricNames:        properties.MetricNames,
 		ResourceAttributes: properties.Resources,
-	}
+	}, nil
 }