[CORL-824] Feature Flags (#2756)

* feat: implemented feature flag

* fix: support deprecated enums

src/core/server/graph/tenant/mutators/Settings.ts

@@ -1,7 +1,16 @@
 import TenantContext from "coral-server/graph/tenant/context";
-import { GQLUpdateSettingsInput } from "coral-server/graph/tenant/schema/__generated__/types";
 import { Tenant } from "coral-server/models/tenant";
-import { regenerateSSOKey, update } from "coral-server/services/tenant";
+import {
+  disableFeatureFlag,
+  enableFeatureFlag,
+  regenerateSSOKey,
+  update,
+} from "coral-server/services/tenant";
+
+import {
+  GQLFEATURE_FLAG,
+  GQLUpdateSettingsInput,
+} from "coral-server/graph/tenant/schema/__generated__/types";
 
 export const Settings = ({
   mongo,
@@ -15,4 +24,8 @@ export const Settings = ({
     update(mongo, redis, tenantCache, config, tenant, input.settings),
   regenerateSSOKey: (): Promise<Tenant | null> =>
     regenerateSSOKey(mongo, redis, tenantCache, tenant, now),
+  enableFeatureFlag: (flag: GQLFEATURE_FLAG) =>
+    enableFeatureFlag(mongo, redis, tenantCache, tenant, flag),
+  disableFeatureFlag: (flag: GQLFEATURE_FLAG) =>
+    disableFeatureFlag(mongo, redis, tenantCache, tenant, flag),
 });

src/core/server/graph/tenant/resolvers/Mutation.ts

@@ -229,4 +229,12 @@ export const Mutation: Required<GQLMutationTypeResolver<void>> = {
     user: await ctx.mutators.Users.deleteModeratorNote(input),
     clientMutationId: input.clientMutationId,
   }),
+  enableFeatureFlag: async (source, { input }, ctx) => ({
+    flags: await ctx.mutators.Settings.enableFeatureFlag(input.flag),
+    clientMutationId: input.clientMutationId,
+  }),
+  disableFeatureFlag: async (source, { input }, ctx) => ({
+    flags: await ctx.mutators.Settings.disableFeatureFlag(input.flag),
+    clientMutationId: input.clientMutationId,
+  }),
 };

src/core/server/graph/tenant/resolvers/Settings.ts

@@ -1,6 +1,21 @@
-import { GQLSettingsTypeResolver } from "coral-server/graph/tenant/schema/__generated__/types";
 import { Tenant } from "coral-server/models/tenant";
 
+import {
+  GQLFEATURE_FLAG,
+  GQLSettingsTypeResolver,
+} from "coral-server/graph/tenant/schema/__generated__/types";
+
+const filterValidFeatureFlags = () => {
+  // Compute the valid flags based on this enum.
+  const flags = Object.values(GQLFEATURE_FLAG);
+
+  // Return a type guard for the feature flag.
+  return (flag: string | GQLFEATURE_FLAG): flag is GQLFEATURE_FLAG =>
+    flags.includes(flag);
+};
+
 export const Settings: GQLSettingsTypeResolver<Tenant> = {
   slack: ({ slack = {} }) => slack,
+  featureFlags: ({ featureFlags = [] }) =>
+    featureFlags.filter(filterValidFeatureFlags()),
 };

src/core/server/graph/tenant/schema/schema.graphql

@@ -333,6 +333,14 @@ type ActionPresence {
 ## Settings
 ################################################################################
 
+enum FEATURE_FLAG {
+  """
+  DISABLE_WARN_USER_OF_TOXIC_COMMENT when enabled will turn off warnings for
+  toxic comments.
+  """
+  DISABLE_WARN_USER_OF_TOXIC_COMMENT
+}
+
 # The moderation mode of the site.
 enum MODERATION_MODE {
   """
@@ -967,7 +975,6 @@ type SlackChannelTriggers {
   featuredComments is whether this channel will receive featured comments
   """
   featuredComments: Boolean!
-
 }
 
 type SlackChannel {
@@ -1323,6 +1330,11 @@ type Settings {
   """
   stories: StoryConfiguration! @auth(roles: [ADMIN])
 
+  """
+  featureFlags provides the enabled feature flags.
+  """
+  featureFlags: [FEATURE_FLAG!]! @auth(roles: [ADMIN])
+
   """
   createdAt is the time that the Settings was created at.
   """
@@ -3480,7 +3492,6 @@ input SlackTriggersConfigurationInput {
   featuredComments is whether this channel will receive featured comments
   """
   featuredComments: Boolean
-
 }
 
 input SlackChannelConfigurationInput {
@@ -5247,6 +5258,62 @@ type RequestUserCommentsDownloadPayload {
   archiveURL: String!
 }
 
+#########################
+# enableFeatureFlag
+#########################
+
+input EnableFeatureFlagInput {
+  """
+  clientMutationId is required for Relay support.
+  """
+  clientMutationId: String!
+
+  """
+  flag is the feature flag to create.
+  """
+  flag: FEATURE_FLAG!
+}
+
+type EnableFeatureFlagPayload {
+  """
+  clientMutationId is required for Relay support.
+  """
+  clientMutationId: String!
+
+  """
+  flags is the current set of flags enabled.
+  """
+  flags: [FEATURE_FLAG!]!
+}
+
+#########################
+# disableFeatureFlag
+#########################
+
+input DisableFeatureFlagInput {
+  """
+  clientMutationId is required for Relay support.
+  """
+  clientMutationId: String!
+
+  """
+  flag is the feature flag to delete.
+  """
+  flag: FEATURE_FLAG!
+}
+
+type DisableFeatureFlagPayload {
+  """
+  clientMutationId is required for Relay support.
+  """
+  clientMutationId: String!
+
+  """
+  flags is the current set of flags enabled.
+  """
+  flags: [FEATURE_FLAG!]!
+}
+
 ##################
 ## Mutation
 ##################
@@ -5605,6 +5672,19 @@ type Mutation {
   deleteModeratorNote(
     input: DeleteModeratorNoteInput!
   ): DeleteModeratorNotePayload! @auth(roles: [ADMIN, MODERATOR])
+
+  """
+  enableFeatureFlag will enable a given FEATURE_FLAG.
+  """
+  enableFeatureFlag(input: EnableFeatureFlagInput!): EnableFeatureFlagPayload!
+    @auth(roles: [ADMIN])
+
+  """
+  disableFeatureFlag will disable a given FEATURE_FLAG
+  """
+  disableFeatureFlag(
+    input: DisableFeatureFlagInput!
+  ): DisableFeatureFlagPayload! @auth(roles: [ADMIN])
 }
 
 ##################

src/core/server/models/tenant/helpers.ts

@@ -1,13 +1,16 @@
 import crypto from "crypto";
 import { FluentBundle } from "fluent/compat";
 
+import { translate } from "coral-server/services/i18n";
+
 import {
+  GQLFEATURE_FLAG,
   GQLReactionConfiguration,
   GQLStaffConfiguration,
 } from "coral-server/graph/tenant/schema/__generated__/types";
-import { translate } from "coral-server/services/i18n";
 
 import { SSOKey } from "../settings";
+import { Tenant } from "./tenant";
 
 export const getDefaultReactionConfiguration = (
   bundle: FluentBundle
@@ -46,3 +49,21 @@ export function generateSSOKey(createdAt: Date): SSOKey {
 
   return { kid, secret, createdAt };
 }
+
+/**
+ * hasFeatureFlag will check to see if the Tenant has a particular feature flag
+ * enabled.
+ *
+ * @param tenant the Tenant to test for a feature flag
+ * @param flag the FEATURE_FLAG to check for
+ */
+export function hasFeatureFlag(
+  tenant: Pick<Tenant, "featureFlags">,
+  flag: GQLFEATURE_FLAG
+) {
+  if (tenant.featureFlags && tenant.featureFlags.includes(flag)) {
+    return true;
+  }
+
+  return false;
+}

src/core/server/models/tenant/tenant.ts

@@ -6,14 +6,16 @@ import { DEFAULT_SESSION_LENGTH } from "coral-common/constants";
 import { LanguageCode } from "coral-common/helpers/i18n/locales";
 import { DeepPartial, Omit, Sub } from "coral-common/types";
 import { dotize } from "coral-common/utils/dotize";
-import {
-  GQLMODERATION_MODE,
-  GQLSettings,
-} from "coral-server/graph/tenant/schema/__generated__/types";
 import { Settings } from "coral-server/models/settings";
 import { I18n } from "coral-server/services/i18n";
 import { tenants as collection } from "coral-server/services/mongodb/collections";
 
+import {
+  GQLFEATURE_FLAG,
+  GQLMODERATION_MODE,
+  GQLSettings,
+} from "coral-server/graph/tenant/schema/__generated__/types";
+
 import {
   generateSSOKey,
   getDefaultReactionConfiguration,
@@ -40,6 +42,11 @@ export interface TenantSettings
    * locale is the specified locale for this Tenant.
    */
   locale: LanguageCode;
+
+  /**
+   * featureFlags is the set of flags enabled on this Tenant.
+   */
+  featureFlags?: GQLFEATURE_FLAG[];
 }
 
 /**
@@ -337,3 +344,51 @@ export async function rotateTenantSSOKey(
 
   return result.value || null;
 }
+
+export async function enableTenantFeatureFlag(
+  mongo: Db,
+  id: string,
+  flag: GQLFEATURE_FLAG
+) {
+  // Update the Tenant.
+  const result = await collection(mongo).findOneAndUpdate(
+    { id },
+    {
+      // Add the flag to the set of enabled flags.
+      $addToSet: {
+        featureFlags: flag,
+      },
+    },
+    {
+      // False to return the updated document instead of the original
+      // document.
+      returnOriginal: false,
+    }
+  );
+
+  return result.value || null;
+}
+
+export async function disableTenantFeatureFlag(
+  mongo: Db,
+  id: string,
+  flag: GQLFEATURE_FLAG
+) {
+  // Update the Tenant.
+  const result = await collection(mongo).findOneAndUpdate(
+    { id },
+    {
+      // Pull the flag from the set of enabled flags.
+      $pull: {
+        featureFlags: flag,
+      },
+    },
+    {
+      // False to return the updated document instead of the original
+      // document.
+      returnOriginal: false,
+    }
+  );
+
+  return result.value || null;
+}

src/core/server/services/comments/pipeline/phases/toxic.ts

@@ -14,6 +14,7 @@ import { Omit } from "coral-common/types";
 import { ToxicCommentError } from "coral-server/errors";
 import logger from "coral-server/logger";
 import { ACTION_TYPE } from "coral-server/models/action/comment";
+import { hasFeatureFlag } from "coral-server/models/tenant";
 import {
   IntermediateModerationPhase,
   IntermediatePhaseResult,
@@ -23,6 +24,7 @@ import {
 import {
   GQLCOMMENT_FLAG_REASON,
   GQLCOMMENT_STATUS,
+  GQLFEATURE_FLAG,
   GQLPerspectiveExternalIntegration,
 } from "coral-server/graph/tenant/schema/__generated__/types";
 
@@ -118,7 +120,20 @@ export const toxic: IntermediateModerationPhase = async ({
 
       // Throw an error if we're nudging instead of recording.
       if (nudge) {
-        throw new ToxicCommentError(model, score, threshold);
+        // Only if the feature flag for disabling this behavior is not enabled.
+        if (
+          !hasFeatureFlag(
+            tenant,
+            GQLFEATURE_FLAG.DISABLE_WARN_USER_OF_TOXIC_COMMENT
+          )
+        ) {
+          throw new ToxicCommentError(model, score, threshold);
+        } else {
+          log.trace(
+            { flag: GQLFEATURE_FLAG.DISABLE_WARN_USER_OF_TOXIC_COMMENT },
+            "not nudging because of feature experiment"
+          );
+        }
       }
 
       return {

src/core/server/services/tenant/index.ts

@@ -12,6 +12,8 @@ import {
   createTenant,
   CreateTenantInput,
   createTenantSSOKey,
+  disableTenantFeatureFlag,
+  enableTenantFeatureFlag,
   rotateTenantSSOKey,
   Tenant,
   updateTenant,
@@ -19,6 +21,7 @@ import {
 import { I18n } from "coral-server/services/i18n";
 
 import {
+  GQLFEATURE_FLAG,
   GQLSettingsInput,
   GQLSettingsWordListInput,
 } from "coral-server/graph/tenant/schema/__generated__/types";
@@ -196,3 +199,57 @@ export async function discoverOIDCConfiguration(issuerString: string) {
   // Discover the configuration.
   return discover(issuer);
 }
+
+export async function enableFeatureFlag(
+  mongo: Db,
+  redis: Redis,
+  cache: TenantCache,
+  tenant: Tenant,
+  flag: GQLFEATURE_FLAG
+) {
+  // If the Tenant already has this flag, don't bother adding it again.
+  if (tenant.featureFlags && tenant.featureFlags.includes(flag)) {
+    return tenant.featureFlags;
+  }
+
+  // Enable the feature flag.
+  const updated = await enableTenantFeatureFlag(mongo, tenant.id, flag);
+  if (!updated || !updated.featureFlags) {
+    // As we just added the feature flag, we would expect that the Tenant would
+    // always have the feature flags set to some array.
+    throw new Error("tenant not found");
+  }
+
+  // Update the tenant cache.
+  await cache.update(redis, updated);
+
+  // Return the updated feature flags.
+  return updated.featureFlags;
+}
+
+export async function disableFeatureFlag(
+  mongo: Db,
+  redis: Redis,
+  cache: TenantCache,
+  tenant: Tenant,
+  flag: GQLFEATURE_FLAG
+) {
+  // If the feature flag doesn't exist on the Tenant (or the Tenant has no
+  // feature flags), don't bother trying to remove it again.
+  if (!tenant.featureFlags || !tenant.featureFlags.includes(flag)) {
+    return tenant.featureFlags || [];
+  }
+
+  // Remove the feature flag.
+  const updated = await disableTenantFeatureFlag(mongo, tenant.id, flag);
+  if (!updated) {
+    throw new Error("tenant not found");
+  }
+
+  // Update the tenant cache.
+  await cache.update(redis, updated);
+
+  // Return the updated feature flags (or [] if there was no feature flags to
+  // begin with).
+  return updated.featureFlags || [];
+}