Try Micronaut or Honey, I have reduced the framework

Try Micronaut or Honey, I have reduced the framework

About micronaut framework, I caught a glimpse of the mailing list digest. I wondered what kind of animal it was. The framework is set in contrast to the Spring stuffed with all the necessary tools.

Anticipating the upcoming conference for developers, where they would just tell and show how to use micronaut in your microservices, I decided to prepare at least once and come at least with some context in my head, with a certain set of problems and questions. Run homework, so to speak. I decided to relax some small pet-project for a couple of evenings (as it goes). At the end of the article there will be a link to the repository of all project sources.

Micronaut is a JVM framework, supports three development languages: Java, Kotlin, Groovy. It was developed by OCI, the same company that gave us Grails. It has a clipping in the form of a cli-application and a set of recommended libraries (various reactive-http and database clients)

There is a DI that implements and repeats the ideas of Spring, adding a number of its own chips - asynchronous, support for AWS Lambda, Client Side Load Balancing.

The idea of ​​the service: a friend of mine once bought a half-dozen assorted cryptocurrencies with a fool, investing in non-consumed vacation pay and a nest of a winter jacket. We all know that the volatility of this whole cryptocurrency substance is wild, and the topic itself is generally unpredictable, a friend eventually decided to take care of his nerves and just forget about what happens to his “assets”. But sometimes you still want to look, but what about all this is suddenly rich. So the idea of ​​a simple panel (dashboard, like Grafana or something simpler) appeared, a certain web page with dry information, how much it all costs now in a certain fiat currency (USD, RUR).

Disclaimers

1. Let us leave the expediency of writing our own solution overboard; we just need to try out the new framework on something smarter than HelloWorld.
2. Calculation algorithm, expected errors, errors, etc. (at least for the first phase of the product), the validity of the choice of cryptobirds for pulling information, a friend’s “investment” crypto portfolio will also be out of the bracket and not subject to discussion or any deep analytics.

So, a small set of requirements:

1. Web service (access from the outside, via http)
2. Display of the page in the browser with a summary of the total value of the cryptocurrency portfolio
3. Ability to configure the portfolio (choose JSON format for loading and unloading the structure of the portfolio). Some REST API for updating the portfolio and loading it, i.e. 2 API: to save / update - POST, to upload - GET. The structure of the portfolio is essentially a simple form of the form.
   

   BTC –  0.00005 . XEM –  4.5 . ... 

4. Data is taken from cryptobirth and currency exchange sources (for fiat currencies)
5. Rules for calculating the total value of the portfolio:
   
   

Of course, everything that is written in clause 5 is the subject of separate disputes and doubts, but let it be that business wanted it that way.

Project start

So, go to the framework's official website and see how we can start developing. The official site offers to install the sdkman tool. A thing that facilitates the development and management of projects on the micronaut framework (and others including, for example, Grails).

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A small remark: If you just start project initialization without any keys, then by default the gradle collector is selected. Delete the folder, try again, this time with the key:

 mn create-app com.room606.cryptonaut -b=maven 

An interesting point is also that, like Spring Tool Suite, sdkman offers you at the stage of creating a project to ask which “cubes” you want to use at the start. I didn’t experiment with that much, I also created it with a default preset.

Finally, we open the project in Intellij Idea and admire the set of sources and resources and blanks that supplied us with a wizard for creating a micronaut project.

The eye clings to the Dockerfile file

 FROM openjdk:8u171-alpine3.7 RUN apk --no-cache add curl COPY target/cryptonaut*.jar cryptonaut.jar CMD java ${JAVA_OPTS} -jar cryptonaut.jar 

Well, this is fun and commendable. We were immediately equipped with a tool to quickly output the application to the Prod / INT / QA / whatever environment. For this mental plus sign to the project.

All you need to do is to build the Maven project, then build the Docker image and publish it to your Docker registry, or simply export the image binaries as an option to your CI system, as you please.

In the resource folder, we also prepared a blank for us with application configuration parameters (similar to application.properties in Spring), as well as a config file for the logback library. Cool!

We go to the entry point of the application and study the class. We see a picture painfully familiar to us from Spring Boot. Here, the developers of the framework also did not become wise and invent anything.

 public static void main(String[] args) throws IOException { Micronaut.run(Application.class); } 

Compare it with the familiar Spring code.

 public static void main(String[] args) { SpringApplication.run(Application.class, args); } 

Those. we also raise the IoC container with all the bins that come into operation as they are needed. A little run on the official documentation, slowly begin development.

We will need:

1. Domain Models
2. Controllers for implementing REST API.
3. Data storage layer (Database client or ORM or something else)
4. The code of consumers of data from cryptographic and fiat currency exchange data. Those. we need to write the simplest customers for 3rd party services. In Spring, RestTemplate known to us was well suited for this role.
5. The minimum configuration for flexible management and application start (think about what and how we will make in the configuration)
6. Tests! Yes, in order to confidently and safely code and implement new functionality we need to be confident in the stability of the old
7. Caching This is not a basic requirement, but something that would be nice to have for good performance, and in our scenario there are places where caching is definitely a good tool.
   Spoiler: here everything goes very bad.

Domain Models

The following models will suffice for our purposes: cryptocurrency portfolio models, fiat currency exchange rates, fiat currency cryptocurrency prices, total portfolio value.

Below is the code for only pairs of models, the rest can be viewed in the repository . And yes, I was too lazy to screw Lombok on this project.

 Portfolio.java package com.room606.cryptonaut.domain; import java.math.BigDecimal; import java.util.Collections; import java.util.Map; import java.util.TreeMap; public class Portfolio { private Map<String, BigDecimal> coins = Collections.emptyMap(); public Map<String, BigDecimal> getCoins() { return new TreeMap<>(coins); } public void setCoins(Map<String, BigDecimal> coins) { this.coins = coins; } 

 FiatRate.java package com.room606.cryptonaut.domain; import java.math.BigDecimal; public class FiatRate { private String base; private String counter; private BigDecimal value; public FiatRate(String base, String counter, BigDecimal value) { this.base = base; this.counter = counter; this.value = value; } public String getBase() { return base; } public void setBase(String base) { this.base = base; } public String getCounter() { return counter; } public void setCounter(String counter) { this.counter = counter; } public BigDecimal getValue() { return value; } public void setValue(BigDecimal value) { this.value = value; } } 

 Price.java ... Prices.java () ... Total.java ... 

Controllers

We try to write a controller that implements the simplest API, issuing the cost of cryptocurrency for given letter codes of coins.
Those.

 GET /cryptonaut/restapi/prices.json?coins=BTC&coins=ETH&fiatCurrency=RUR 

Must issue something like:

 {"prices":[{"coin":"BTC","value":407924.043300000000},{"coin":"ETH","value":13040.638266000000}],"fiatCurrency":"RUR"} 

According to the documentation , nothing complicated and resembles the same approaches and conventions of Spring :

 package com.room606.cryptonaut.rest; import com.room606.cryptonaut.domain.Price; import com.room606.cryptonaut.domain.Prices; import com.room606.cryptonaut.markets.FiatExchangeRatesService; import com.room606.cryptonaut.markets.CryptoMarketDataService; import io.micronaut.http.MediaType; import io.micronaut.http.annotation.*; import java.util.List; import java.util.stream.Collectors; import java.util.stream.Stream; @Controller("/cryptonaut/restapi/") public class MarketDataController { private final CryptoMarketDataService cryptoMarketDataService; private final FiatExchangeRatesService fiatExchangeRatesService; public MarketDataController(CryptoMarketDataService cryptoMarketDataService, FiatExchangeRatesService fiatExchangeRatesService) { this.cryptoMarketDataService = cryptoMarketDataService; this.fiatExchangeRatesService = fiatExchangeRatesService; } @Get("/prices.json") @Produces(MediaType.APPLICATION_JSON) public Prices pricesAsJson(@QueryValue("coins") String[] coins, @QueryValue("fiatCurrency") String fiatCurrency) { return getPrices(coins, fiatCurrency); } private Prices getPrices(String[] coins, String fiatCurrency) { List<Price> prices = Stream.of(coins) .map(coin -> new Price(coin, cryptoMarketDataService.getPrice(coin, fiatCurrency))) .collect(Collectors.toList()); return new Prices(prices, fiatCurrency); } } 

Those. we calmly indicate our POJO returned type, and without configuring any serializers / deserializers, even without hanging additional Micronaut annotations from the box, build the correct http body with the data. Let's compare with the Spring way:

 @RequestMapping(value = "/prices.json", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_UTF8_VALUE) public ResponseEntity<Prices> pricesAsJson(@RequestParam("userId") final String[] coins, @RequestParam("fiatCurrency") String fiatCurrency) { 

In general, I had no problems with controllers, they just worked as expected from them, according to the documentation. Their writing was intuitive and simple. Moving on.

Data storage layer

For the first version of the application, we will store only the user's portfolio. In general, we will store only one portfolio of one user. Simply put, we will not yet have support for a multitude of users, only one main user with his cryptocurrency portfolio. That's cool!

For the implementation of data persistence, the documentation offers variants with JPA connections, as well as fragmentary examples of using various clients to read from the database (section “12.1.5 Configuring Postgres”). JPA strongly discarded and preference was given to handwriting requests and manipulating them. The database configuration has been added to application.yml ( Postgres was selected as the RDBMS), according to the documentation:

 postgres: reactive: client: port: 5432 host: localhost database: cryptonaut user: crypto password: r1ch13r1ch maxSize: 5 

A postgres-reactive library has been added. This is a client for working with the database both in an asynchronous manner and in a synchronous manner.

 <dependency> <groupId>io.micronaut.configuration</groupId> <artifactId>postgres-reactive</artifactId> <version>1.0.0.M4</version> <scope>compile</scope> </dependency> 

And, finally, a docker-compose.yml file was added to the / docker-compose.yml to deploy the future environment of our application, where the database component was added:

 db: image: postgres:9.6 restart: always environment: POSTGRES_USER: crypto POSTGRES_PASSWORD: r1ch13r1ch POSTGRES_DB: cryptonaut ports: - 5432:5432 volumes: - ${PWD}/../db/init_tables.sql:/docker-entrypoint-initdb.d/1.0.0_init_tables.sql 

Below is the initialization script database with a very simple table structure:

 CREATE TABLE portfolio ( id serial CONSTRAINT coin_amt_primary_key PRIMARY KEY, coin varchar(16) NOT NULL UNIQUE, amount NUMERIC NOT NULL ); 

Now we will try to distribute the code that updates the user's portfolio. Our component for working with the portfolio will look like this:

 package com.room606.cryptonaut; import com.room606.cryptonaut.domain.Portfolio; import java.math.BigDecimal; import java.util.Optional; public interface PortfolioService { Portfolio savePortfolio(Portfolio portfolio); Portfolio loadPortfolio(); Optional<BigDecimal> calculateTotalValue(Portfolio portfolio, String fiatCurrency); } 

Looking at the set of client methods of the Postgres reactive client We throw in this class:

 package com.room606.cryptonaut; import com.room606.cryptonaut.domain.Portfolio; import com.room606.cryptonaut.markets.CryptoMarketDataService; import io.micronaut.context.annotation.Requires; import io.reactiverse.pgclient.Numeric; import io.reactiverse.reactivex.pgclient.*; import javax.inject.Inject; import java.math.BigDecimal; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.Optional; import java.util.stream.Collectors; public class PortfolioServiceImpl implements PortfolioService { private final PgPool pgPool; ... private static final String UPDATE_COIN_AMT = "INSERT INTO portfolio (coin, amount) VALUES (?, ?) ON CONFLICT (coin) " + "DO UPDATE SET amount = ?"; ... public Portfolio savePortfolio(Portfolio portfolio) { List<Tuple> records = portfolio.getCoins() .entrySet() .stream() .map(entry -> Tuple.of(entry.getKey(), Numeric.create(entry.getValue()), Numeric.create(entry.getValue()))) .collect(Collectors.toList()); pgPool.preparedBatch(UPDATE_COIN_AMT, records, pgRowSetAsyncResult -> { //   pgRowSetAsyncResult.cause().printStackTrace(); }); return portfolio; } ... } 

We start the environment, try to update our portfolio through the prudently implemented in advance API:

 package com.room606.cryptonaut.rest; import com.room606.cryptonaut.PortfolioService; import com.room606.cryptonaut.domain.Portfolio; import io.micronaut.http.MediaType; import io.micronaut.http.annotation.*; import javax.inject.Inject; @Controller("/cryptonaut/restapi/") public class ConfigController { @Inject private PortfolioService portfolioService; @Post("/portfolio") @Produces(MediaType.APPLICATION_JSON) @Consumes(MediaType.APPLICATION_JSON) public Portfolio savePortfolio(@Body Portfolio portfolio) { return portfolioService.savePortfolio(portfolio); } 

Perform a curl request:

 curl http://localhost:8080/cryptonaut/restapi/portfolio -X POST -H "Content-Type: application/json" --data '{"coins": {"XRP": "35.5", "LSK": "5.03", "XEM": "16.23"}}' -v 

And ... we catch an error in the logs:

 io.reactiverse.pgclient.PgException: syntax error at or near "," at io.reactiverse.pgclient.impl.PrepareStatementCommand.handleErrorResponse(PrepareStatementCommand.java:74) at io.reactiverse.pgclient.impl.codec.decoder.MessageDecoder.decodeError(MessageDecoder.java:250) at io.reactiverse.pgclient.impl.codec.decoder.MessageDecoder.decodeMessage(MessageDecoder.java:139) ... 

Having scratched our turnips, we don’t find any solution in the official dock, we try to google the dock for the postgres-reactive , and this turns out to be the right solution, as there are detailed examples and the correct query syntax. The point was in the placeholder parameters, it turns out that you need to apply numbered tags of the form $x ($1, $2, etc.) . So the fix is ​​to rewrite the target query:

 private static final String UPDATE_COIN_AMT = "INSERT INTO portfolio (coin, amount) VALUES ($1, $2) ON CONFLICT (coin) " + "DO UPDATE SET amount = $3"; 

Restart the application, try the same REST request ... hurray. The data is added up. Let's go on to read.

We are faced with the simplest task to read the user's cryptocurrency portfolio from the database and map them to a POJO object. For these purposes, we use the pgPool.query method (SELECT_COINS_AMTS, pgRowSetAsyncResult):

 public Portfolio loadPortfolio() { Map<String, BigDecimal> coins = new HashMap<>(); pgPool.query(SELECT_COINS_AMTS, pgRowSetAsyncResult -> { if (pgRowSetAsyncResult.succeeded()) { PgRowSet rows = pgRowSetAsyncResult.result(); PgIterator pgIterator = rows.iterator(); while (pgIterator.hasNext()) { Row row = pgIterator.next(); coins.put(row.getString("coin"), new BigDecimal(row.getFloat("amount"))); } } else { System.out.println("Failure: " + pgRowSetAsyncResult.cause().getMessage()); } }); Portfolio portfolio = new Portfolio(); portfolio.setCoins(coins); return portfolio; } 

We connect all this together with the controller responsible for the cryptocurrency portfolio:

 @Controller("/cryptonaut/restapi/") public class ConfigController { ... @Get("/portfolio") @Produces(MediaType.APPLICATION_JSON) public Portfolio loadPortfolio() { return portfolioService.loadPortfolio(); } ... 

Restart the service. For testing, first fill this very portfolio with at least some data:

 curl http://localhost:8080/cryptonaut/restapi/portfolio -X POST -H "Content-Type: application/json" --data '{"coins": {"XRP": "35.5", "LSK": "5.03", "XEM": "16.23"}}' -v 

Now finally test our code reading from the database:

 curl http://localhost:8080/cryptonaut/restapi/portfolio -v 

And ... we get ... something strange:

 {"coins":{}} 

Pretty strange isn't it? We recheck the request ten times, try to make the curl request again, even restart our service. The result is still the same wild ... After reading the signature of the method, and also remembering that we have a Reactive Pg client , we come to the conclusion that we are dealing with asynchronous. Thoughtful debag confirmed this! It was worth a little slowly podobezhit code, like voila, we returned non-empty data!

Once again, referring to the library dock, rolling up our sleeves to rewrite the code on a truly blocking, but completely predictable:

 Map<String, BigDecimal> coins = new HashMap<>(); PgIterator pgIterator = pgPool.rxPreparedQuery(SELECT_COINS_AMTS).blockingGet().iterator(); while (pgIterator.hasNext()) { Row row = pgIterator.next(); coins.put(row.getString("coin"), new BigDecimal(row.getValue("amount").toString())); } 

Now we get what we expect. This problem was solved, moving on.

We write the client to obtain data on the markets

Here, of course, I would like to solve the problem with the least amount of bicycles. The result was two solutions:

• ready-made client libraries for accessing specific cryptochemicals
• a small, personally written client code for applying for the exchange rate. It came in handy that out of the box offers Micronaut.

With ready libraries everything is not so interesting. I will only note that during a quick search, the project https://github.com/knowm/XChange was chosen.

In principle, the library's architecture is as simple as two kopecks - there is a set of interfaces for receiving data, main interfaces and classes of Ticker models (you can learn bid , ask , all sorts of open price, close price etc.), CurrencyPair , Currency . Further, you initialize the implementations themselves in the code by first connecting the implementation with the implementation that addresses the specific crypto-exchange for this purpose. And the main class through which we act is MarketDataService.java

For example, for our experiments, for the beginning, we will be satisfied with this “configuration”:

 <dependency> <groupId>org.knowm.xchange</groupId> <artifactId>xchange-core</artifactId> <version>4.3.10</version> </dependency> <dependency> <groupId>org.knowm.xchange</groupId> <artifactId>xchange-bittrex</artifactId> <version>4.3.10</version> </dependency> 

Below is the code that performs the key function - calculating the value of a particular cryptocurrency in fiat terms (see the Formulas described in the beginning of the article in the requirements block):

 package com.room606.cryptonaut.markets; import com.room606.cryptonaut.exceptions.CryptonautException; import org.knowm.xchange.currency.Currency; import org.knowm.xchange.currency.CurrencyPair; import org.knowm.xchange.dto.marketdata.Ticker; import org.knowm.xchange.exceptions.CurrencyPairNotValidException; import org.knowm.xchange.service.marketdata.MarketDataService; import javax.inject.Inject; import javax.inject.Singleton; import java.io.IOException; import java.math.BigDecimal; @Singleton public class CryptoMarketDataService { private final FiatExchangeRatesService fiatExchangeRatesService; private final MarketDataService marketDataService; @Inject public CryptoMarketDataService(FiatExchangeRatesService fiatExchangeRatesService, MarketDataServiceFactory marketDataServiceFactory) { this.fiatExchangeRatesService = fiatExchangeRatesService; this.marketDataService = marketDataServiceFactory.getMarketDataService(); } public BigDecimal getPrice(String coinCode, String fiatCurrencyCode) throws CryptonautException { BigDecimal price = getPriceForBasicCurrency(coinCode, Currency.USD.getCurrencyCode()); if (Currency.USD.equals(new Currency(fiatCurrencyCode))) { return price; } else { return price.multiply(fiatExchangeRatesService.getFiatPrice(Currency.USD.getCurrencyCode(), fiatCurrencyCode)); } } private BigDecimal getPriceForBasicCurrency(String coinCode, String fiatCurrencyCode) throws CryptonautException { Ticker ticker = null; try { ticker = marketDataService.getTicker(new CurrencyPair(new Currency(coinCode), new Currency(fiatCurrencyCode))); return ticker.getBid(); } catch (CurrencyPairNotValidException e) { ticker = getTicker(new Currency(coinCode), Currency.BTC); Ticker ticker2 = getTicker(Currency.BTC, new Currency(fiatCurrencyCode)); return ticker.getBid().multiply(ticker2.getBid()); } catch (IOException e) { throw new CryptonautException("Failed to get price for Pair " + coinCode + "/" + fiatCurrencyCode + ": " + e.getMessage(), e); } } private Ticker getTicker(Currency base, Currency counter) throws CryptonautException { try { return marketDataService.getTicker(new CurrencyPair(base, counter)); } catch (CurrencyPairNotValidException | IOException e) { throw new CryptonautException("Failed to get price for Pair " + base.getCurrencyCode() + "/" + counter.getCurrencyCode() + ": " + e.getMessage(), e); } } } 

Everything here is done as much as possible using our own interfaces in order to slightly abstract away from the specific implementations provided by the project https://github.com/knowm/XChange .

In view of the fact that on many, if not on all cryptobirds in circulation, only a limited set of fiat currencies (USD, EUR, perhaps that's all ..), for the final answer to the user's question, you need to add another source of data - fiat currency rates, and also an additional converter. Those. To answer the question of how much the WTF cryptocurrency in the RUR (target currency, target currency) now costs, you will have to answer two sub-questions: WTF / BaseCurrency (consider that USD), BaseCurrency / RUR, then multiply these two values ​​and return as a result.

For our first version of the service, we will maintain only USD and RUR as target currencies.
So, in order to support RUR, it would be advisable to take sources that are relevant to the geographical location of the service (we will host and use it exclusively in Russia). In short, we are satisfied with the course of the Central Bank. On the Internet, an open source of such data was found, which can be consumed as JSON. Perfectly.

Below is the response of the service to the request for the current exchange rate:

 { "Date": "2018-10-16T11:30:00+03:00", "PreviousDate": "2018-10-13T11:30:00+03:00", "PreviousURL": "\/\/www.cbr-xml-daily.ru\/archive\/2018\/10\/13\/daily_json.js", "Timestamp": "2018-10-15T23:00:00+03:00", "Valute": { "AUD": { "ID": "R01010", "NumCode": "036", "CharCode": "AUD", "Nominal": 1, "Name": "ђІЃ‚Ђ°»№Ѓє№ ґѕ»»°Ђ", "Value": 46.8672, "Previous": 46.9677 }, "AZN": { "ID": "R01020A", "NumCode": "944", "CharCode": "AZN", "Nominal": 1, "Name": "ђ·µЂ±°№ґ¶°ЅЃє№ ј°Ѕ°‚", "Value": 38.7567, "Previous": 38.8889 }, "GBP": { "ID": "R01035", "NumCode": "826", "CharCode": "GBP", "Nominal": 1, "Name": "¤ѓЅ‚ Ѓ‚µЂ»ЅіѕІ ЎѕµґЅµЅЅѕіѕ єѕЂѕ»µІЃ‚І°", "Value": 86.2716, "Previous": 87.2059 }, ... 

Actually, below is the client code CbrExchangeRatesClient :

 package com.room606.cryptonaut.markets.clients; import com.fasterxml.jackson.databind.JsonNode; import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.ObjectReader; import com.room606.cryptonaut.exceptions.CryptonautException; import io.micronaut.http.HttpRequest; import io.micronaut.http.client.Client; import io.micronaut.http.client.RxHttpClient; import javax.inject.Inject; import javax.inject.Singleton; import java.io.IOException; import java.math.BigDecimal; import java.util.*; @Singleton public class CbrExchangeRatesClient { private static final String CBR_DATA_URI = "https://www.cbr-xml-daily.ru/daily_json.js"; @Client(CBR_DATA_URI) @Inject private RxHttpClient httpClient; private final ObjectReader objectReader = new ObjectMapper().reader(); public Map<String, BigDecimal> getRates() { try { //return ratesCache.get("fiatRates"); HttpRequest<?> req = HttpRequest.GET(""); String response = httpClient.retrieve(req, String.class).blockingSingle(); JsonNode json = objectReader.readTree(response); String usdPrice = json.get("Valute").get("USD").get("Value").asText(); String eurPrice = json.get("Valute").get("EUR").get("Value").asText(); String gbpPrice = json.get("Valute").get("GBP").get("Value").asText(); Map<String, BigDecimal> prices = new HashMap<>(); prices.put("USD", new BigDecimal(usdPrice)); prices.put("GBP", new BigDecimal(gbpPrice)); prices.put("EUR", new BigDecimal(eurPrice)); return prices; } catch (IOException e) { throw new CryptonautException("Failed to obtain exchange rates: " + e.getMessage(), e); } } } 

Here we inject RxHttpClient , a component from the Micronaut . It also gives us the choice to do asynchronous request processing or blocking. Choose a classic blocking:

 httpClient.retrieve(req, String.class).blockingSingle(); 

Configuration

In the project, you can highlight things that change and affect business logic or some specific aspects. Let's make a list of supported fiatnnyh currencies as a property and we will inject it at the start of the application.

The following code will discard currency codes for which we are unable to calculate the value of the portfolio for the time being:

 public BigDecimal getFiatPrice(String baseCurrency, String counterCurrency) throws NotSupportedFiatException { if (!supportedCounterCurrencies.contains(counterCurrency)) { throw new NotSupportedFiatException("Counter currency not supported: " + counterCurrency); } Map<String, BigDecimal> rates = cbrExchangeRatesClient.getRates(); return rates.get(baseCurrency); } 

Accordingly, our intention is to somehow inject the value from application.yml into the variable supportedCounterCurrencies .

In the first version such code was written, below the field of the class FiatExchangeRatesService.java:

 @Value("${cryptonaut.currencies:RUR}") private String supportedCurrencies; private final List<String> supportedCounterCurrencies = Arrays.asList(supportedCurrencies.split("[,]", -1)); 

Here, the placeholder corresponds to the following structure of the application.yml document:

 micronaut: application: name: cryptonaut #Uncomment to set server port server: port: 8080 postgres: reactive: client: port: 5432 host: localhost database: cryptonaut user: crypto password: r1ch13r1ch maxSize: 5 # app / business logic specific properties cryptonaut: currencies: "RUR" 

Running the app, quick smoke test ... Error!

 Caused by: io.micronaut.context.exceptions.BeanInstantiationException: Error instantiating bean of type [com.room606.cryptonaut.markets.CryptoMarketDataService] Path Taken: new MarketDataController([CryptoMarketDataService cryptoMarketDataService],FiatExchangeRatesService fiatExchangeRatesService) --> new CryptoMarketDataService([FiatExchangeRatesService fiatExchangeRatesService],MarketDataServiceFactory marketDataServiceFactory) at io.micronaut.context.DefaultBeanContext.doCreateBean(DefaultBeanContext.java:1266) at io.micronaut.context.DefaultBeanContext.createAndRegisterSingleton(DefaultBeanContext.java:1677) at io.micronaut.context.DefaultBeanContext.getBeanForDefinition(DefaultBeanContext.java:1447) at io.micronaut.context.DefaultBeanContext.getBeanInternal(DefaultBeanContext.java:1427) at io.micronaut.context.DefaultBeanContext.getBean(DefaultBeanContext.java:852) at io.micronaut.context.AbstractBeanDefinition.getBeanForConstructorArgument(AbstractBeanDefinition.java:943) ... 36 common frames omitted Caused by: java.lang.NullPointerException: null at com.room606.cryptonaut.markets.FiatExchangeRatesService.<init>(FiatExchangeRatesService.java:20) at com.room606.cryptonaut.markets.$FiatExchangeRatesServiceDefinition.build(Unknown Source) at io.micronaut.context.DefaultBeanContext.doCreateBean(DefaultBeanContext.java:1252) ... 41 common frames omitted 

Micronaut Spring , compile time . , :

 @Value("${cryptonaut.currencies:RUR}") private String supportedCurrencies; private List<String> supportedCounterCurrencies; @PostConstruct void init() { supportedCounterCurrencies = Arrays.asList(supportedCurrencies.split("[,]", -1)); } 

, – javax.annotation.PostConstruct , , , , . .

, , Spring. micronaut @Property Map<String, String> , @Configuration , Random Properties (, ID , , - ) PropertySourceLoader , .. . Spring – ApplicationContext ( xml , web , groovy , ClassPath etc.) , .

Tests

, micronaut. Embedded Server feature, Groovy Spock . Java , groovy- . , EmbeddedServer + HttpClient Micronaut API —

 GET /cryptonaut/restapi/portfolio/total.json?fiatCurrency={x} 

API, .

:

 public class PortfolioReportsControllerTest { private static EmbeddedServer server; private static HttpClient client; @Inject private PortfolioService portfolioService; @BeforeClass public static void setupServer() { server = ApplicationContext.run(EmbeddedServer.class); client = server .getApplicationContext() .createBean(HttpClient.class, server.getURL()); } @AfterClass public static void stopServer() { if(server != null) { server.stop(); } if(client != null) { client.stop(); } } @Test public void total() { //TODO: Seems like code smell. I don't like it.. portfolioService = server.getApplicationContext().getBean(PortfolioService.class); Portfolio portfolio = new Portfolio(); Map<String, BigDecimal> coins = new HashMap<>(); BigDecimal amt1 = new BigDecimal("570.05"); BigDecimal amt2 = new BigDecimal("2.5"); coins.put("XRP", amt1); coins.put("QTUM", amt2); portfolio.setCoins(coins); portfolioService.savePortfolio(portfolio); HttpRequest request = HttpRequest.GET("/cryptonaut/restapi/portfolio/total.json?fiatCurrency=USD"); HttpResponse<Total> rsp = client.toBlocking().exchange(request, Total.class); assertEquals(200, rsp.status().getCode()); assertEquals(MediaType.APPLICATION_JSON_TYPE, rsp.getContentType().get()); Total val = rsp.body(); assertEquals("USD", val.getFiatCurrency()); assertEquals(TEST_VALUE.toString(), val.getValue().toString()); assertEquals(amt1.toString(), val.getPortfolio().getCoins().get("XRP").toString()); assertEquals(amt2.toString(), val.getPortfolio().getCoins().get("QTUM").toString()); } } 

, mock PortfolioService.java :

 package com.room606.cryptonaut; import com.room606.cryptonaut.domain.Portfolio; import io.micronaut.context.annotation.Requires; import javax.inject.Singleton; import java.math.BigDecimal; import java.util.Optional; @Singleton @Requires(env="test") public class MockPortfolioService implements PortfolioService { private Portfolio portfolio; public static final BigDecimal TEST_VALUE = new BigDecimal("56.65"); @Override public Portfolio savePortfolio(Portfolio portfolio) { this.portfolio = portfolio; return portfolio; } @Override public Portfolio loadPortfolio() { return portfolio; } @Override public Optional<BigDecimal> calculateTotalValue(Portfolio portfolio, String fiatCurrency) { return Optional.of(TEST_VALUE); } } 

@Requires(env="test") , Application Context . -, micronaut test, , . , , PortfolioServiceImpl @Requires(notEnv="test") . – . Micronaut .

, – , , – mockito . :

 @Test public void priceForUsdDirectRate() throws IOException { when(marketDataServiceFactory.getMarketDataService()).thenReturn(marketDataService); String coinCode = "ETH"; String fiatCurrencyCode = "USD"; BigDecimal priceA = new BigDecimal("218.58"); Ticker targetTicker = new Ticker.Builder().bid(priceA).build(); when(marketDataService.getTicker(new CurrencyPair(new Currency(coinCode), new Currency(fiatCurrencyCode)))).thenReturn(targetTicker); CryptoMarketDataService cryptoMarketDataService = new CryptoMarketDataService(fiatExchangeRatesService, marketDataServiceFactory); assertEquals(priceA, cryptoMarketDataService.getPrice(coinCode, fiatCurrencyCode)); } 

, . . , . , , - IP. , @Cacheable .

, . , ( appliction.yml ). redis, Docker- . :

 redis: image: 'bitnami/redis:latest' environment: - ALLOW_EMPTY_PASSWORD=yes ports: - '6379:6379' 

@Cacheable:

 @Cacheable("fiatRates") public Map<String, BigDecimal> getRates() { HttpRequest<?> req = HttpRequest.GET(""); String response = httpClient.retrieve(req, String.class).blockingSingle(); try { JsonNode json = objectReader.readTree(response); String usdPrice = json.get("Valute").get("USD").get("Value").asText(); String eurPrice = json.get("Valute").get("EUR").get("Value").asText(); String gbpPrice = json.get("Valute").get("GBP").get("Value").asText(); Map<String, BigDecimal> prices = new HashMap<>(); prices.put("USD", new BigDecimal(usdPrice)); prices.put("GBP", new BigDecimal(gbpPrice)); prices.put("EUR", new BigDecimal(eurPrice)); return prices; } catch (IOException e) { throw new RuntimeException(e); } } 

application.yml . . :

 caches: fiatrates: expireAfterWrite: "1h" redis: caches: fiatRates: expireAfterWrite: "1h" port: 6379 server: localhost 

:

 #cache redis: uri: localhost:6379 caches: fiatRates: expireAfterWrite: "1h" 

. — “Unexpected error occurred: No cache configured for name: fiatRates”:

 ERROR imhsnetty.RoutingInBoundHandler - Unexpected error occurred: No cache configured for name: fiatRates io.micronaut.context.exceptions.ConfigurationException: No cache configured for name: fiatRates at io.micronaut.cache.DefaultCacheManager.getCache(DefaultCacheManager.java:67) at io.micronaut.cache.interceptor.CacheInterceptor.interceptSync(CacheInterceptor.java:176) at io.micronaut.cache.interceptor.CacheInterceptor.intercept(CacheInterceptor.java:128) at io.micronaut.aop.MethodInterceptor.intercept(MethodInterceptor.java:41) at io.micronaut.aop.chain.InterceptorChain.proceed(InterceptorChain.java:147) at com.room606.cryptonaut.markets.clients.$CbrExchangeRatesClientDefinition$Intercepted.getRates(Unknown Source) at com.room606.cryptonaut.markets.FiatExchangeRatesService.getFiatPrice(FiatExchangeRatesService.java:30) at com.room606.cryptonaut.rest.MarketDataController.index(MarketDataController.java:34) at com.room606.cryptonaut.rest.$MarketDataControllerDefinition$$exec2.invokeInternal(Unknown ... 

GitHub - SO . . , . , . boilerplate-, - Redis - , , Spring Boot , .

, Micronaut – , Spring-.

Disclaimer-: , -, , ( , , , ).

, :

OS: 16.04.1-Ubuntu x86_64 x86_64 x86_64 GNU/Linux
CPU: Intel® Core(TM) i7-7700HQ CPU @ 2.80GHz
Mem: 2 8 Gb DDR4, Speed: 2400 MHz
SSD Disk: PCIe NVMe M.2, 256

defense :

4. API,
5. API – “” .

– Rest Controller – IoC-, .

“ ” :

	Micronaut	Spring Boot
Avg.(ms)	2708.4	2735.2
cryptonaut (ms)	1082	-

, – 27 Micronaut . , .

?

. , , , – . . Groovy-, , . SO Spring. , , . — . Spring.

:

• Micronaut – service-discovery, AWS
• authorization
• Java. Kotlin Groovy.

.