Gazebo_simulation-Backend/README.md

# Developer Documentation - Spiri Simulator Backend


**Steps to install and access Backend server APIs:**

- System - Ubuntu 18.04
- Install maven and Java- 11 to your Ubuntu machine
- sudo apt update
- sudo apt install maven
- sudo apt install default-jdk



**Install mysql- 5.7 (https://www.digitalocean.com/community/tutorials/how-to-install-mysql-on-ubuntu-18-04)**
- $ sudo apt update
- $ sudo apt install mysql-server
- $ Configuring mysql
- $ sudo mysql_secure_installation
- Note:  Set password plugin- Initially set it to ‘yes’ and level ‘0’ for validation policy
- Adjusting User Authentication and Privileges



**Add scripts to mysql server**
- Run below command to add scripts from (cloned**) backend folder into in installed my sql server
- mysql -u username -p database_name < file.sql
 **Scripts are in the db table :https://gitlab.pleiadesrobotics.com/web-services/backend/-/tree/feature_base_code/db
- Install Eclipse
    Download Eclipse from https://www.eclipse.org/downloads/
- Setup eclipse with tar xfz ~/Downloads/eclipse-inst-linux64.tar.gz ~/Downloads/eclipse-installer/eclipse-inst
- Setup eclipse for lombok getter & setter 
- Copy lombok-1.18.6.jar from ../.m2/repository/org/projectlombok/lombok/1.18.6 to eclipse root folder(where eclipse.ini file is)
- cd <'eclipse root directory'>
- java -jar lombok-1.18.6.jar install ~/eclipse/jee-2020-03/eclipse/
- java -jar lombok.jar install ~/eclipse/jee-2020-03/eclipse/

####    Or 

- cd <'eclipse root directory'>
- java -jar eclipse/lombok-1.18.6.jar 
- install ~/Downloads/eclipse-java-2020-03-R-linux-gtk-x86_64/eclipse/
- Restart eclipse and build again the project

**Build & Run  - Backend:**
- git clone git@gitlab.pleiadesrobotics.com:web-services/backend.git
- Update ~/backend/src/main/resources/application.yml with mysql password set
- cd backend
- mvn clean install
- mvn spring-boot:run
- Open localhost:8080/task/list/ to test everything runs OK. It will run the backend server at port 8080 default.

**Understanding Backend Codebase:**

***src/main/java*** 
     
###### com.example.springbootapp
-     This is the main class to run your complete application.

###### Com.example.springbootapp.config
-     Configuration files for adding the security

###### Com.example.springbootapp.controllers
-     Once you want a new microservice add this to the package and create new class with the tag “Get   
      mapping” so basically on the hit to the URL the page is redirected as per the functionality written here.
      Usually after a hit it opens up the specific implementation written in the package relevant to the   
      specific class in “com.example.springbootapp.services”.

###### com.example.springbootapp.model
-     POJO (Plain OLd Java Objects) for all the functionality are added here these are basic getter and setter methods that you require.

###### Com.example.springbootapp.repository
-     Here interfaces are defined which are extending JPA(database connection to your db) then these 

###### com.example.springbootapp.schedulers
-     service to stop the container spawned using AWS when not being used.     
      

###### com.example.springbootapp.services
-     This usually has an interface and an implementation of that interface which is for having the best     
      practise of loose coupling. So for example 
       
       CompetitionService.java is the interface and CompetitionServiceImpl.java is the class. So all the  
       methods that are defined in the interface are implemented in this service implementation.
       /backend/src/main/java/com/example/springbootapp/services/CompetitionService.java
       /backend/src/main/java/com/example/springbootapp/services/CompetitionServiceImpl.java


#### src/main/resources
-      Here the application yml files and the properties file is kept
       You can add the following things for example :  
                  Set the mysql db
                  Set the okta Oauth 2 authentication etc
       Example :- https://gitlab.spirirobotics.com/web-services/backend/-/blob/feature_base_code/src/main/resources/application.yml


#### src/test/java
-      Use Junit  or Mockito to add your unit test cases 
       Junit :     https://junit.org/junit5/
       Mockito:   https://site.mockito.org/


**APIs details:**
- To CRUD applications (Competitions)
https://developer.okta.com/docs/reference/api/apps/

- To CRUD groups (Teams)
https://developer.okta.com/docs/reference/api/groups/

- To CRUD users
https://developer.okta.com/docs/reference/api/users/

- To get a user Id from our backend abstracted user API
[/api/user](url)

    This Api returns current okta session user object from where you can retrieve userId from "sub"
    
    {"at_hash":"cBwzHrq22cIYxBd1g3851g","sub":"00u21ycq02wVcoFxT357","zoneinfo":"America/Los_Angeles","ver":1,"email_verified":true,"amr":["pwd"],"iss":"https://dev-125890.okta.com/oauth2/default","preferred_username":"raga.amber@gmail.com","locale":"en-US","given_name":"Raghav","aud":["0oa21yqmlw0cI8weJ357"],"updated_at":1576023483,"idp":"00o21ycpwwDPVJJEi357","auth_time":1576967436,"name":"Raghav Sharma","exp":"2019-12-21T23:56:24Z","family_name":"Sharma","iat":"2019-12-21T22:56:24Z","email":"raga.amber@gmail.com","jti":"ID.LCHoKAbPBXVCs0LjnXY2v54q9wnUMQZXBW5o0poI8GQ"}

- To log out current user (Post)
[/api/logout](url) Pass idToken to be timed out, this api will call okta to make token invalid.

- To get competition progress (Get)
[/competition/progress/{user_id}/{comp_id}](url)
This will return you all tasks. Construct your task list using this response.

- To create a simulator (Get) (TODO: Change it to post call)
[/simulator/start/{user_id}/{name}/{pwd}](url) where user_id is student okta id, name is given_name, pwd is any constant.
This API returns 'publicIp' which is a Fargate container IP to access newly created simulator and shell.

- To update task (Get) (TODO: Change it to post call)
[/competition/update/${userId}/${compId}/${taskId}](url)

- To create/update master data task (Put)
[/task/update](url)

    {
        "user_id":11,"comp_id":13,"task_id":1,"task_name":"Is simulator launched ?","task_progress":"0", "task_action":"Launch Simulator"
    }

- To log heart beat to active simulator against student id (Get) (TODO: Change it to post call)
[/simulator/logheartbeat/{user_id}](url)

- To stop/delete active simulator against student id (Get) (TODO: Change it to post call)
[/simulator/stop/{user_id}](url)
****

**Behavior flow:**
( 'Team <-> Okta Group' 
'Competition <-> Okta Application(App)')
- Create a team in Okta.
- Create a user and add it to a team in Okta.
- Create a competition and add a team to competition in Okta.
- Front end can call any API as dummy API to pop up Okta login page.
- Once login passed, get userId from login session directly from Okta.
 (OR)
 Use Okta user API /api/v1/users/me
 (OR)
 Use abrstacted user api[/api/user] from backend.

- Get competition details from Okta apps api for the user by using below API:

  {{url}}/api/v1/apps?filter=user.id+eq+"{{userId}}"

  This will get you competitionId(appid)
- Now call competition progress API by passing user id and competition id to get competition tasks progress details
    [/competition/progress/{user_id}/{comp_id}](url)
  This will return you all tasks details for the competition. Construct your task list using this response.
   
- Create a simulator by calling [/simulator/start/{user_id}/{name}/{pwd}](url) and place the returned URI from API to your respective tasks buttons.   
 (Note: This API takes longer time to respond if simulator is getting created first time. Please use enough timeout at frontend.)

- Call simulator heart beat api periodically from frontend to keep the simulator active [/simulator/logheartbeat/{user_id}](url) which updates the timestamp of the simulator.
  If heartbeat api is not called, then simulator would be deleted automatically after 1 hr.
  There is a scheduler runs periodically at backend which checks the timestamp of created simulator and if simulator timestamp is 1 hr old then it makes an assumption that simulator is not in use.

- Stop/Delete simulator: To stop/delete simulator, use this api [/simulator/stop/{user_id}](url)


##  Understand Cloud

- Credentials :
- SHELLINABOX_PASSWORD   spiri-friend2019@
- SHELLINABOX_USER    Raghav
- Gazebo http://3.235.54.48:8080/
- Shell terminal http://3.235.54.48:4200/
- Once you are inside the shell using the above credentials then you just need to run the following command to spawn a gazebo instance :

### AWS Fargate :

- ECR technology to deploy serevr less docker containers 
- https://aws.amazon.com/fargate/
- Ask your network adimintrator at Spiri to give you the credentials and create a I AM USER account for you to do backend testing.


## Install Postman(For checking backend APIs)

- https://developer.okta.com/code/rest/
After you set all the global variables here then hit the following URL :
{{url}}/api/v1/users?limit=25
Output :
    {
        "id": "00u21ycq02wVcoFxT357",
        "status": "ACTIVE",
        "created": "2019-11-30T01:42:45.000Z",
        "activated": null,
        "statusChanged": "2019-11-30T01:44:07.000Z",
        "lastLogin": "2020-05-19T16:35:09.000Z",
        "lastUpdated": "2019-11-30T01:44:08.000Z",
        "passwordChanged": "2019-11-30T01:44:07.000Z",
        "type": {
            "id": "oty21ycpxjH4TjHD1357"

## Redirect from backend :
- HttpHeaders headers = new HttpHeaders();
headers.add("Location", "localhost:3000/");    
return new ResponseEntity(headers, HttpStatus.FOUND);


## Important articles and developer documentations :

- https://docs.google.com/document/d/1fABunlJQTq6DFNJTzCgDcGphiXBCHzwtk5RZju8drmk/edit?usp=sharing   (If you cannot access this link then ask Patrick to add you to it)
- https://developer.okta.com/blog/2020/03/27/spring-oidc-logout-options
- https://developer.okta.com/code/rest/