telemetry: improve inline docstrings (#57104)

(cherry picked from commit 8b32774)

Author: bobheadxi

cmd/frontend/graphqlbackend/telemetry.graphql

@@ -51,6 +51,9 @@ input TelemetryEventInput {
 
     """
     Optional marketing campaign tracking parameters.
+
+    🚨 SECURITY: This metadata is NEVER exported from private Sourcegraph instances,
+    and is only exported for events tracked in the public Sourcegraph.com instance.
     """
     marketingTracking: TelemetryEventMarketingTrackingInput
 }
@@ -60,9 +63,7 @@ Properties comprising the source of a telemetry V2 event reported by a client.
 """
 input TelemetryEventSourceInput {
     """
-    Source client of the event. Clients must come from a static set of predefined
-    metadata keys in libraries - it is left as a string in the API to allow some
-    backwards/forwards flexibility.
+    Source client of the event.
     """
     client: String!
     """
@@ -88,7 +89,9 @@ input TelemetryEventParametersInput {
     Private metadata in JSON format. Unlike metadata, values can be of any type,
     not just numeric.
 
-    By default, this metadata is assumed to be unsafe for export from an instance.
+    🚨 SECURITY: This metadata is NOT exported from instances by default, as it
+    can contain arbitrarily-shaped data that may accidentally contain sensitive
+    or private contents.
     """
     privateMetadata: JSONValue
     """
@@ -102,12 +105,12 @@ A single, PII-free metadata item for telemetry V2 events.
 """
 input TelemetryEventMetadataInput {
     """
-    Metadata keys must come from a static set of predefined metadata keys in
-    libraries - it is left as a string in the API to allow some flexibility.
+    The key identifying this metadata entry.
     """
     key: String!
     """
-    Numeric value associated with the key.
+    Numeric value associated with the key. Enforcing numeric values eliminates
+    risks of accidentally shipping sensitive or private data.
     """
     value: Int!
 }
@@ -135,7 +138,8 @@ input TelemetryEventBillingMetadataInput {
 """
 Marketing campaign tracking parameters for a telemetry V2 event.
 
-By default, this metadata is assumed to be unsafe for export from an instance.
+🚨 SECURITY: This metadata is NEVER exported from private Sourcegraph instances,
+and is only exported for events tracked in the public Sourcegraph.com instance.
 """
 input TelemetryEventMarketingTrackingInput {
     """

internal/telemetrygateway/v1/telemetrygateway.pb.go

@@ -100,17 +100,20 @@ message Event {
   optional EventFeatureFlags feature_flags = 8;
   // Optional marketing campaign tracking parameters.
   //
-  // 🚨 SECURITY: Do NOT export this metadata by default, as it can contain
-  // sensitive data. Currently, only Sourcegraph.com should export this.
+  // 🚨 SECURITY: This metadata is NEVER exported from an instance, and is only
+  // exported for events tracked in the public Sourcegraph.com instance.
   optional EventMarketingTracking marketing_tracking = 9;
 }
 
 message EventSource {
   message Server {
+    // Version of the Sourcegraph server.
     string version = 1;
   }
   message Client {
+    // Source client of the event.
     string name = 1;
+    // Version of the cleint.
     optional string version = 2;
   }
 
@@ -122,18 +125,22 @@ message EventSource {
 
 message EventParameters {
   // Version of the event parameters, used for indicating the "shape" of this
-  // event's metadata, beginning at 0.
+  // event's metadata, beginning at 0. Useful for denoting if the shape of
+  // metadata has changed in any way.
   int32 version = 1;
-  // Strictly typed metadata, restricted to integer values.
+  // Strictly typed metadata, restricted to integer values to avoid accidentally
+  // exporting sensitive or private data.
   map<string, int64> metadata = 2;
   // Additional potentially sensitive metadata - i.e. not restricted to integer
   // values.
-
-  // 🚨 SECURITY: Do NOT export this metadata by default, as it can contain
-  // arbitrarily-shaped data that may accidentally contain sensitive contents.
   //
-  // This should only be exported on an allowlist basis based on combinations
-  // of event feature and action, alongside careful audit of callsites.
+  // 🚨 SECURITY: This metadata is NOT exported from instances by default, as it
+  // can contain arbitrarily-shaped data that may accidentally contain sensitive
+  // or private contents.
+  //
+  // This metadata is only exported on an allowlist basis based on terms of
+  // use agreements and combinations of event feature and action, alongside
+  // careful audit of callsites.
   optional google.protobuf.Struct private_metadata = 3;
   // Optional billing-related metadata.
   optional EventBillingMetadata billing_metadata = 4;
@@ -147,13 +154,14 @@ message EventBillingMetadata {
 }
 
 message EventUser {
-  // Database user ID of signed in user.
+  // Database user ID of signed in user. User IDs are specific to a Sourcegraph
+  // instance, and not universal.
   //
   // We use an int64 as an ID because in Sourcegraph, database user IDs are
   // always integers.
   optional int64 user_id = 1;
-  // Randomized unique identifier for client (i.e. stored in localstorage in web
-  // client).
+  // Randomized unique identifier for an actor (e.g. stored in localstorage in
+  // web client).
   optional string anonymous_user_id = 2;
 }
 
@@ -167,13 +175,26 @@ message EventFeatureFlags {
   map<string, string> flags = 1;
 }
 
+// Marketing campaign tracking metadata.
+//
+// 🚨 SECURITY: This metadata is NEVER exported from private Sourcegraph
+// instances, and is only exported for events tracked in the public
+// Sourcegraph.com instance.
 message EventMarketingTracking {
+  // URL the event occurred on.
   optional string url = 1;
+  // Initial URL the user landed on.
   optional string first_source_url = 2;
+  // Cohort ID to identify the user as part of a specific A/B test.
   optional string cohort_id = 3;
+  // Referrer URL that refers the user to Sourcegraph.
   optional string referrer = 4;
+  // Last source URL visited by the user.
   optional string last_source_url = 5;
+  // Device session ID to identify the user's session.
   optional string device_session_id = 6;
+  // Session referrer URL for the user.
   optional string session_referrer = 7;
+  // First URL the user visited in their current session.
   optional string session_first_url = 8;
 }