[extension/opamp] Rely on Collector APIs for config redaction (#34078)

**Description:**

Now that
open-telemetry/opentelemetry-collector#10139 is
merged, we can rely on the Collector APIs to redact sensitive fields in
the config for us.

I tested this against the latest Collector core commit with the goal
that this will land in the v0.105.0 release.

.chloggen/unredact-effective-config.yaml

@@ -0,0 +1,29 @@
+# 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: extension/opamp
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Rely on the Collector APIs to do config redaction
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [34078]
+
+# (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: |
+  Previously all config fields had to be redacted, now `configopaque.String` is used to determine
+  which fields should be redacted. As a result, fields that are not sensitive are no longer redacted.
+
+# 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: []

extension/opampextension/opamp_agent.go

@@ -30,13 +30,6 @@ import (
 	"github.com/open-telemetry/opentelemetry-collector-contrib/extension/opampcustommessages"
 )
 
-const redactedVal = "[REDACTED]"
-
-// Paths that will not have values redacted when reporting the effective config.
-var unredactedPaths = []string{
-	"service::pipelines",
-}
-
 type opampAgent struct {
 	cfg    *Config
 	logger *zap.Logger
@@ -285,46 +278,6 @@ func (o *opampAgent) updateAgentIdentity(instanceID uuid.UUID) {
 	o.instanceID = instanceID
 }
 
-func redactConfig(cfg any, parentPath string) {
-	switch val := cfg.(type) {
-	case map[string]any:
-		for k, v := range val {
-			path := parentPath
-			if path == "" {
-				path = k
-			} else {
-				path += "::" + k
-			}
-			// We don't want to redact certain parts of the config
-			// that are known not to contain secrets, e.g. pipelines.
-			for _, p := range unredactedPaths {
-				if p == path {
-					return
-				}
-			}
-			switch x := v.(type) {
-			case map[string]any:
-				redactConfig(x, path)
-			case []any:
-				redactConfig(x, path)
-			default:
-				val[k] = redactedVal
-			}
-		}
-	case []any:
-		for i, v := range val {
-			switch x := v.(type) {
-			case map[string]any:
-				redactConfig(x, parentPath)
-			case []any:
-				redactConfig(x, parentPath)
-			default:
-				val[i] = redactedVal
-			}
-		}
-	}
-}
-
 func (o *opampAgent) composeEffectiveConfig() *protobufs.EffectiveConfig {
 	o.eclk.RLock()
 	defer o.eclk.RUnlock()
@@ -334,7 +287,6 @@ func (o *opampAgent) composeEffectiveConfig() *protobufs.EffectiveConfig {
 	}
 
 	m := o.effectiveConfig.ToStringMap()
-	redactConfig(m, "")
 	conf, err := yaml.Marshal(m)
 	if err != nil {
 		o.logger.Error("cannot unmarshal effectiveConfig", zap.Any("conf", o.effectiveConfig), zap.Error(err))

extension/opampextension/opamp_agent_test.go

@@ -175,8 +175,7 @@ func TestComposeEffectiveConfig(t *testing.T) {
 	ecFileName := filepath.Join("testdata", "effective.yaml")
 	cm, err := confmaptest.LoadConf(ecFileName)
 	assert.NoError(t, err)
-	redactedFileName := filepath.Join("testdata", "effective-redacted.yaml")
-	expected, err := os.ReadFile(redactedFileName)
+	expected, err := os.ReadFile(ecFileName)
 	assert.NoError(t, err)
 
 	o.updateEffectiveConfig(cm)