Merge pull request 'Environment variable option for minimum teacher vote selection count' (#95) from minimum-teacher-selection-amount into main

Reviewed-on: mentorenwahl/mentorenwahl#95

.example.env

@@ -22,6 +22,7 @@ POSTGRES_USER="mw"
 POSTGRES_PASSWORD=
 
 # Backend
+BACKEND_MINIMUM_TEACHER_SELECTION_COUNT=
 BACKEND_URL=URL
 # Backend - API
 BACKEND_API_GRAPHQL_PLAYGROUND=false

docker-compose.yml

@@ -77,6 +77,7 @@ services:
       - redis
     environment:
       BACKEND_URL: ${URL}
+      BACKEND_MINIMUM_TEACHER_SELECTION_COUNT: ${BACKEND_MINIMUM_TEACHER_SELECTION_COUNT}
       BACKEND_API_GRAPHQL_PLAYGROUND: ${BACKEND_API_GRAPHQL_PLAYGROUND}
       BACKEND_API_JWT_SECRET: ${BACKEND_API_JWT_SECRET}
       BACKEND_API_JWT_EXPIRATION: ${BACKEND_API_JWT_EXPIRATION}

docker/backend/shard.lock

@@ -30,7 +30,7 @@ shards:
 
   graphql:
     git: https://github.com/graphql-crystal/graphql.git
-    version: 0.3.2+git.commit.8c6dc73c0c898ca511d9d12efefca7c837c25946
+    version: 0.3.2+git.commit.75325d512bfa2f57a14b306aa9f7465fc0998fa5
 
   habitat:
     git: https://github.com/luckyframework/habitat.git

docker/backend/shard.yml

@@ -37,7 +37,7 @@ dependencies:
     github: will/crystal-pg
   graphql:
     github: graphql-crystal/graphql
-    branch: master
+    branch: main
   jwt:
     github: crystal-community/jwt
   commander:

docker/backend/src/backend/api/schema/config.cr

@@ -0,0 +1,30 @@
+# Mentorenwahl: A fullstack application for assigning mentors to students based on their whishes.
+# Copyright (C) 2022  Dominic Grimm
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+module Backend
+  module Api
+    module Schema
+      @[GraphQL::Object]
+      # Public configuration of the API for frontend pre-validation
+      class Config < GraphQL::BaseObject
+        @[GraphQL::Field]
+        def minimum_teacher_selection_count : Int32
+          Backend.config.minimum_teacher_selection_count
+        end
+      end
+    end
+  end
+end

docker/backend/src/backend/api/schema/mutation.cr

@@ -143,7 +143,7 @@ module Backend
         def create_vote(context : Context, input : VoteCreateInput) : Vote
           context.student!
 
-          raise "Not enough teachers" if input.teacher_ids.empty?
+          raise "Not enough teachers" if input.teacher_ids.size < Backend.config.minimum_teacher_selection_count
           teacher_role_count = Db::User.where(role: Db::UserRole::Teacher.to_s).count.run.as(Int64)
           raise "Teachers not registered" if teacher_role_count != Db::Teacher.count ||
                                              teacher_role_count.zero?

docker/backend/src/backend/api/schema/query.cr

@@ -25,6 +25,12 @@ module Backend
           true
         end
 
+        @[GraphQL::Field]
+        # Public configuration of the API for frontend pre-validation
+        def config : Config
+          Config.new
+        end
+
         @[GraphQL::Field]
         # Current authenticated user
         def me(context : Context) : User

docker/backend/src/backend/config.cr

@@ -58,6 +58,9 @@ module Backend
     # Base URL of application
     getter url : String
 
+    # Minimum teacher selection count
+    getter minimum_teacher_selection_count : Int32
+
     @[EnvConfig::Setting(key: "api")]
     # Configuration for `Api`
     getter api : ApiConfig