sahilbadla / svc-playerdb

svc-playerdb

Demo microservice application that loads player profiles from a csv file. This csv is loaded at startup(see PlayerdbApplication.java) from location src/main/resources/People.csv

Technology

Following libraries were used during the development of this microservice :

• Spring Boot - Server side framework
• Docker - Containerizing framework
• H2 - in memory relational database
• Swagger - API documentation
• Lombok - Annotation plugin/processor
• Spring actuator - Production readiness components
• Micrometer - Prometheus registry to expose metric
• Gradle - Dependency management

RUN

go to svc-playerdb root folder and run the following command to build the project:

./gradlew clean build

Run as docker:

docker-compose up --build

To run with cpu/memory limits, use the following command. This works only in docker v3.0 and above:

docker-compose --compatibility up --build

Service will run on port 8080 by default which could be accessed at http://localhost:8080/

REST API

The service should expose these REST endpoints:

• GET /api/players - returns the list of all players
• GET /api/players/paginated - returns the list of all players in paginated fashion
• GET /api/players/{playerID} - returns a single player by ID
• PUT /api/players/{playerID}/weight - increments a player's weight by 1
• PUT /api/players/{playerID}/height - increments a player's height by 1

Response

Custom response type:

public class Response<T> {

   private Status status;
   private T payload;
   private Object errors;
   private Object metadata;
}

Example Json output from GET /api/players/{playerID}

{
    "status": "OK",
    "payload": {
        "playerID": "aaronto01",
        "birthYear": 1939,
        "birthMonth": 8,
        "birthDay": 5,
        "birthCountry": "USA",
        "birthState": "AL",
        "birthCity": "Mobile",
        "deathYear": 1984,
        "deathMonth": 8,
        "deathDay": 16,
        "deathCountry": "USA",
        "deathState": "GA",
        "deathCity": "Atlanta",
        "nameFirst": "Tommie",
        "nameLast": "Aaron",
        "nameGiven": "Tommie Lee",
        "weight": 190,
        "height": 75,
        "bats": "R",
        "playerThrows": "R",
        "debut": "1962-04-10",
        "finalGame": "1971-09-26",
        "retroID": "aarot101",
        "bbrefID": "aaronto01"
    }
}

Example error response

{
    "status": "NOT_FOUND",
    "errors": {
        "timestamp": "2020-11-30T23:36:14.028+00:00",
        "message": "Requested Player with id - aaronto01ss was not found.",
        "details": "Requested Player with id - aaronto01ss was not found."
    }
}

Dependency injection

This project uses Autowired annotation driven dependency injection

Exceptions

Exceptions and its types are defined in package com.intuit.playerdb.exceptions We could throw an exception like:

throw exception(PLAYER, ENTITY_NOT_FOUND, PlayerID);

This results in clubbing the names of these two enums PLAYER(player) and ENTITY_NOT_FOUND(not.found) and coming up with a key player.not.found which is present in the application.properties files as follows :

player.not.found=Requested Player with id - {0} was not found.

Production readiness components

Actuator

The spring-boot-actuator module provides all of Spring Boot’s production-ready features. The simplest way to enable the features is to add a dependency to the spring-boot-starter-actuator

Setup:

Add the following dependency in build.gradle file

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-actuator'
}

List of all actuator endpoints will be available here http://localhost:8080/actuator/

Some of the features are turned off by default. We can enable them by adding following line in application.properties management.endpoints.web.exposure.include=*

Components can be accessed now via http. Following is the endpoint for healthcheck http://localhost:8080/actuator/health

Metrics: http://localhost:8080/actuator/metrics

Open api Swagger

The springdoc suite of java libraries are all about automating the generation of machine and human readable specifications for JSON APIs written using the spring family of projects

Setup:

Add the following dependencies in build.gradle file

dependencies {
    implementation ''org.springdoc:springdoc-openapi-ui:1.5.0''
}

Swagger ui: http://localhost:8080/swagger-ui.html#/

Docker Setup

Dockerfile and docker-compose.yml have been created manually

Logging

Spring boot offers logback for logging by default. To change the logging level, add the following lines in application.properties

logging.level.root=WARN logging.level.com.intuit=TRACE

Other than that I've also implemented request/response logging at Controller & Service level using Aspect and Logging Filter. See com.intuit.playerdb.logging package for implementation. Example of log statements below:

svc-playerdb | 2020-11-30 23:32:29.122  INFO 1 --- [nio-8080-exec-5] c.i.p.logging.filter.LoggingFilter       : GET : /api/players/aaronto01
svc-playerdb | 2020-11-30 23:32:29.140 TRACE 1 --- [nio-8080-exec-5] c.intuit.playerdb.service.PlayerService  : [Enter : PlayerService.fetchPlayerById(..)] with args [aaronto01]
svc-playerdb | 2020-11-30 23:32:29.154 TRACE 1 --- [nio-8080-exec-5] c.intuit.playerdb.service.PlayerService  : [Exit : PlayerService.fetchPlayerById(..)] with return type [class com.intuit.playerdb.model.Player] and value [Player(playerID=aaronto01, birthYear=1939, birthMonth=8, birthDay=5, birthCountry=USA, birthState=AL, birthCity=Mobile, deathYear=1984, deathMonth=8, deathDay=16, deathCountry=USA, deathState=GA, deathCity=Atlanta, nameFirst=Tommie, nameLast=Aaron, nameGiven=Tommie Lee, weight=190, height=75, bats=R, pThrows=R, debut=1962-04-10, finalGame=1971-09-26, retroID=aarot101, bbrefID=aaronto01)]
svc-playerdb | 2020-11-30 23:32:29.188  INFO 1 --- [nio-8080-exec-5] c.i.p.logging.filter.LoggingFilter       : Completed : 200

Tracing

Tracing is part of Actuator. We just need to modify our application.properties file to include the httpTrace endpoint:

management.endpoints.web.exposure.include=httptrace

Trace logs can be accessed at http://localhost:8080/actuator/httptrace

Further enhancements(out of scope for this demo)

Although the project contains certain level of production readiness and production like structure, there are a couple more things that could be implemented to make it more efficient. Below are some of the example:

• Database - This project uses H2 in-memory database. This should be changed eventually and H2 could be used while running locally.
• Design patterns such as Factory, Template etc - We could make use of factory and template design patterns to make the code more flexible and reusable and various levels such as service/repository.
• Testing - Support for testing(unit, integration, end-to-end, performance)
• Logging - Logging wrapper could be enhanced to be more intelligent about context and formatting
• Security - Support for security of endpoints
• Custom middlewares - We could add custom middlewares for processing in request/response