Plugins: Angular detector: Remote patterns fetching (#69843)

* Plugins: Angular detector: Remote patterns fetching

* Renamed PatternType to GCOMPatternType

* Renamed files

* Renamed more files

* Moved files again

* Add type checks, unexport GCOM structs

* Cache failures, update log messages, fix GCOM URL

* Fail silently for unknown pattern types, update docstrings

* Fix tests

* Rename gcomPattern.Value to gcomPattern.Pattern

* Refactoring

* Add FlagPluginsRemoteAngularDetectionPatterns feature flag

* Fix tests

* Re-generate feature flags

* Add TestProvideInspector, renamed TestDefaultStaticDetectorsInspector

* Add TestProvideInspector

* Add TestContainsBytesDetector and TestRegexDetector

* Renamed getter to provider

* More tests

* TestStaticDetectorsProvider, TestSequenceDetectorsProvider

* GCOM tests

* Lint

* Made detector.detect unexported, updated docstrings

* Allow changing grafana.com URL

* Fix API path, add more logs

* Update tryUpdateRemoteDetectors docstring

* Use angulardetector http client

* Return false, nil if module.js does not exist

* Chore: Split angualrdetector into angularinspector and angulardetector packages

Moved files around, changed references and fixed tests:
- Split the old angulardetector package into angular/angulardetector and angular/angularinspector
- angulardetector provides the detection structs/interfaces (Detector, DetectorsProvider...)
- angularinspector provides the actual angular detection service used directly in pluginsintegration
- Exported most of the stuff that was private and now put into angulardetector, as it is not required by angularinspector

* Renamed detector.go -> angulardetector.go and inspector.go -> angularinspector.go

Forgot to rename those two files to match the package's names

* Renamed angularinspector.ProvideInspector to angularinspector.ProvideService

* Renamed "harcoded" to "static" and "remote" to "dynamic"

from PR review, matches the same naming schema used for signing keys fetching

* Fix merge conflict on updated angular patterns

* Removed GCOM cache

* Renamed Detect to DetectAngular and Detector to AngularDetector

* Fix call to NewGCOMDetectorsProvider in newDynamicInspector

* Removed unused test function newError500GCOMScenario

* Added angularinspector service definition in pluginsintegration

* Moved dynamic inspector into pluginsintegration

* Move gcom angulardetectorsprovider into pluginsintegration

* Log errUnknownPatternType at debug level

* re-generate feature flags

* fix error log

pkg/plugins/manager/loader/angular/angulardetector/angulardetector.go

@@ -0,0 +1,69 @@
+package angulardetector
+
+import (
+	"bytes"
+	"context"
+	"regexp"
+)
+
+var (
+	_ AngularDetector = &ContainsBytesDetector{}
+	_ AngularDetector = &RegexDetector{}
+
+	_ DetectorsProvider = &StaticDetectorsProvider{}
+	_ DetectorsProvider = SequenceDetectorsProvider{}
+)
+
+// AngularDetector implements a check to see if a js file is using angular APIs.
+type AngularDetector interface {
+	// DetectAngular takes the content of a js file and returns true if the plugin is using Angular.
+	DetectAngular(js []byte) bool
+}
+
+// ContainsBytesDetector is an AngularDetector that returns true if module.js contains the "pattern" string.
+type ContainsBytesDetector struct {
+	Pattern []byte
+}
+
+// DetectAngular returns true if moduleJs contains the byte slice d.pattern.
+func (d *ContainsBytesDetector) DetectAngular(moduleJs []byte) bool {
+	return bytes.Contains(moduleJs, d.Pattern)
+}
+
+// RegexDetector is an AngularDetector that returns true if the module.js content matches a regular expression.
+type RegexDetector struct {
+	Regex *regexp.Regexp
+}
+
+// DetectAngular returns true if moduleJs matches the regular expression d.regex.
+func (d *RegexDetector) DetectAngular(moduleJs []byte) bool {
+	return d.Regex.Match(moduleJs)
+}
+
+// DetectorsProvider can provide multiple AngularDetectors used for Angular detection.
+type DetectorsProvider interface {
+	// ProvideDetectors returns a slice of AngularDetector.
+	ProvideDetectors(ctx context.Context) []AngularDetector
+}
+
+// StaticDetectorsProvider is a DetectorsProvider that always returns a pre-defined slice of AngularDetector.
+type StaticDetectorsProvider struct {
+	Detectors []AngularDetector
+}
+
+func (p *StaticDetectorsProvider) ProvideDetectors(_ context.Context) []AngularDetector {
+	return p.Detectors
+}
+
+// SequenceDetectorsProvider is a DetectorsProvider that wraps a slice of other DetectorsProvider, and returns the first
+// provided result that isn't empty.
+type SequenceDetectorsProvider []DetectorsProvider
+
+func (p SequenceDetectorsProvider) ProvideDetectors(ctx context.Context) []AngularDetector {
+	for _, provider := range p {
+		if detectors := provider.ProvideDetectors(ctx); len(detectors) > 0 {
+			return detectors
+		}
+	}
+	return nil
+}