Refactor instructor privilege APIs to reduce granularity

[wkurniawan07]

Current: the instructor privilege-related APIs work in a granular way, e.g. only fetch/update course-level, section-level, or session-level privileges depending on the query parameters passed.

teammates/src/main/java/teammates/ui/webapi/GetInstructorPrivilegeAction.java

Lines 137 to 145 in b61a89f

	String sectionName = getRequestParamValue(Const.ParamsNames.SECTION_NAME);
	String feedbackSessionName = getRequestParamValue(Const.ParamsNames.FEEDBACK_SESSION_NAME);
	InstructorPrivilegeData response = constructInstructorPrivileges(instructor, feedbackSessionName);
	if (sectionName != null) {
	response.constructSectionLevelPrivilege(instructor.getPrivileges(), sectionName);
	if (feedbackSessionName != null) {
	response.constructSessionLevelPrivilege(instructor.getPrivileges(), sectionName, feedbackSessionName);
	}
	}

teammates/src/main/java/teammates/ui/webapi/UpdateInstructorPrivilegeAction.java

Lines 51 to 67 in b61a89f

	String sectionName = request.getSectionName();
	String sessionName = request.getFeedbackSessionName();
	Map<String, Boolean> courseLevelPrivilegesMap = request.getAllPresentCourseLevelPrivileges();
	Map<String, Boolean> sectionLevelPrivilegesMap = request.getAllPresentSectionLevelPrivileges();
	Map<String, Boolean> sessionLevelPrivilegesMap = request.getAllPresentSessionLevelPrivileges();
	if (sectionName == null && sessionName == null) {
	updateCourseLevelPrivileges(courseLevelPrivilegesMap, instructorToUpdate);
	updateCourseLevelPrivileges(sectionLevelPrivilegesMap, instructorToUpdate);
	updateCourseLevelPrivileges(sessionLevelPrivilegesMap, instructorToUpdate);
	} else if (sessionName == null) {
	updateSectionLevelPrivileges(sectionName, sectionLevelPrivilegesMap, instructorToUpdate);
	updateSectionLevelPrivileges(sectionName, sessionLevelPrivilegesMap, instructorToUpdate);
	} else {
	updateSessionLevelPrivileges(sectionName, sessionName, sessionLevelPrivilegesMap, instructorToUpdate);
	}

Problems:

• The storage does not match the granularity. The instructor privilege is always saved as one string representing all the instructor's allowed actions, thus fetching/updating part of the privilege have the same DB read/write cost as fetching/updating everything.
• The granularity caused unnecessary burst of requests (both the number and the rate, but especially the rate) for courses where there are large number of sections and sessions. Add that to the fact that each fetch/update operates on the same chunk of data (not part of), and it is not difficult to see the extent of wasted operations we have been doing.
  

  teammates/src/web/app/pages-instructor/instructor-course-edit-page/instructor-course-edit-page.component.ts

  Lines 566 to 615 in b61a89f

  	this.allSections.forEach((sectionName: string) => {
  	const sectionLevelPermission: InstructorSectionLevelPermission = {
  	sectionNames: [sectionName],
  	privilege: {
  	canModifyCourse: false,
  	canModifySession: false,
  	canModifyStudent: false,
  	canModifyInstructor: false,
  	canViewStudentInSections: false,
  	canModifySessionCommentsInSections: false,
  	canViewSessionInSections: false,
  	canSubmitSessionInSections: false,
  	},
  	sessionLevel: [],
  	};
  	permission.sectionLevel.push(sectionLevelPermission);
  	requests.push(this.instructorService.loadInstructorPrivilege({
  	sectionName,
  	courseId: instructor.courseId,
  	instructorEmail: instructor.email,
  	}).pipe(tap((resp: InstructorPrivilege) => {
  	sectionLevelPermission.privilege.canViewStudentInSections = resp.canViewStudentInSections;
  	sectionLevelPermission.privilege.canModifySessionCommentsInSections = resp.canModifySessionCommentsInSections;
  	sectionLevelPermission.privilege.canViewSessionInSections = resp.canViewSessionInSections;
  	sectionLevelPermission.privilege.canSubmitSessionInSections = resp.canSubmitSessionInSections;
  	})));
  	this.allSessions.forEach((sessionName: string) => {
  	requests.push(this.instructorService.loadInstructorPrivilege({
  	sectionName,
  	feedbackSessionName: sessionName,
  	courseId: instructor.courseId,
  	instructorEmail: instructor.email,
  	}).pipe(tap((resp: InstructorPrivilege) => {
  	sectionLevelPermission.sessionLevel.push({
  	sessionName,
  	privilege: {
  	canModifyCourse: false,
  	canModifySession: false,
  	canModifyStudent: false,
  	canModifyInstructor: false,
  	canViewStudentInSections: false,
  	canModifySessionCommentsInSections: resp.canModifySessionCommentsInSections,
  	canViewSessionInSections: resp.canViewSessionInSections,
  	canSubmitSessionInSections: resp.canSubmitSessionInSections,
  	},
  	});
  	})));
  	});
  	});

  
  

  teammates/src/web/app/pages-instructor/instructor-course-edit-page/instructor-course-edit-page.component.ts

  Lines 706 to 745 in b61a89f

  	permission.sectionLevel.forEach((sectionLevel: InstructorSectionLevelPermission) => {
  	sectionLevel.sectionNames.forEach((sectionName: string) => {
  	requests.push(
  	this.instructorService.updateInstructorPrivilege({
  	courseId: instructor.courseId,
  	instructorEmail: instructor.email,
  	requestBody: {
  	sectionName,
  	canViewStudentInSections: sectionLevel.privilege.canViewStudentInSections,
  	canModifySessionCommentsInSections: sectionLevel.privilege.canModifySessionCommentsInSections,
  	canViewSessionInSections: sectionLevel.privilege.canViewSessionInSections,
  	canSubmitSessionInSections: sectionLevel.privilege.canSubmitSessionInSections,
  	} as InstructorPrivilegeUpdateRequest,
  	}).pipe(tap((resp: InstructorPrivilege) => {
  	sectionLevel.privilege.canViewStudentInSections = resp.canViewStudentInSections;
  	sectionLevel.privilege.canModifySessionCommentsInSections = resp.canModifySessionCommentsInSections;
  	sectionLevel.privilege.canViewSessionInSections = resp.canViewSessionInSections;
  	sectionLevel.privilege.canSubmitSessionInSections = resp.canSubmitSessionInSections;
  	})));
  	sectionLevel.sessionLevel.forEach((sessionLevel: InstructorSessionLevelPermission) => {
  	requests.push(
  	this.instructorService.updateInstructorPrivilege({
  	courseId: instructor.courseId,
  	instructorEmail: instructor.email,
  	requestBody: {
  	sectionName,
  	feedbackSessionName: sessionLevel.sessionName,
  	canModifySessionCommentsInSections: sessionLevel.privilege.canModifySessionCommentsInSections,
  	canViewSessionInSections: sessionLevel.privilege.canViewSessionInSections,
  	canSubmitSessionInSections: sessionLevel.privilege.canSubmitSessionInSections,
  	} as InstructorPrivilegeUpdateRequest,
  	}).pipe(tap((resp: InstructorPrivilege) => {
  	sessionLevel.privilege.canModifySessionCommentsInSections = resp.canModifySessionCommentsInSections;
  	sessionLevel.privilege.canViewSessionInSections = resp.canViewSessionInSections;
  	sessionLevel.privilege.canSubmitSessionInSections = resp.canSubmitSessionInSections;
  	})));
  	});
  	});
  	});

Solution:
Simplify the APIs to always fetch/update the entire permission object (thus the update behaving more like a PUT than a PATCH).