pip_services3_components

Description:

pip services3 components

Component definitions for Dart #
This module is a part of the Pip.Services polyglot microservices toolkit.
The Components module contains standard component definitions that can be used to build applications and services.
The module contains the following packages:

Auth - authentication credential stores
Build - basic factories for constructing objects
Cache - distributed cache
Config - configuration readers and managers, whose main task is to deliver configuration parameters to the application from wherever they are being stored
Connect - connection discovery and configuration services
Count - performance counters
Info - context info implementations that manage the saving of process information and sending additional parameter sets
Lock - distributed lock components
Log - basic logging components that provide console and composite logging, as well as an interface for developing custom loggers
Test - minimal set of test components to make testing easier
Component - the root package

Quick links:


Logging


Configuration


API Reference


Change Log


Get Help


Contribute


Examples


Warning!
Config package now not work with condition {{#if var}} something {{/}} in config files.
Use Mustache syntax, for example {{#var}} something {{/var}}


Use #
Add this to your package's pubspec.yaml file:
dependencies:
pip_services3_components: version
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Now you can install package from the command line:
pub get
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Example how to use Logging and Performance counters.
Here we are going to use CompositeLogger and CompositeCounters components.
They will pass through calls to loggers and counters that are set in references.
import 'package:pip_services3_commons/src/config/ConfigParams.dart';
import 'package:pip_services3_commons/src/config/IConfigurable.dart';
import 'package:pip_services3_commons/src/refer/IReferences.dart';
import 'package:pip_services3_commons/src/refer/IReferenceable.dart';
import 'package:pip_services3_components/src/log/CompositeLogger.dart';
import 'package:pip_services3_components/src/count/CompositeCounters.dart';
import 'package:pip_services3_components/src/count/Timing.dart';


class MyComponent implements IConfigurable, IReferenceable {
CompositeLogger _logger = CompositeLogger();
CompositeCounters _counters = CompositeCounters();

configure(ConfigParams config) {
this._logger.configure(config);
}

setReferences(IReferences refs) {
this._logger.setReferences(refs);
this._counters.setReferences(refs);
}

myMethod(String correlationId, dynamic param1) {
try{
this._logger.trace(correlationId, "Executed method mycomponent.mymethod");
this._counters.increment("mycomponent.mymethod.exec_count", 1);
Timing timing = this._counters.beginTiming("mycomponent.mymethod.exec_time");
....
timing.endTiming();
} catch(e) {
this._logger.error(correlationId, e, "Failed to execute mycomponent.mymethod");
this._counters.increment("mycomponent.mymethod.error_count", 1);
}
}
}
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Example how to get connection parameters and credentials using resolvers.
The resolvers support "discovery_key" and "store_key" configuration parameters
to retrieve configuration from discovery services and credential stores respectively.
import 'package:pip_services3_commons/src/config/ConfigParams.dart';
import 'package:pip_services3_commons/src/config/IConfigurable.dart';
import 'package:pip_services3_commons/src/refer/IReferences.dart';
import 'package:pip_services3_commons/src/refer/IReferenceable.dart';
import 'package:pip_services3_commons/src/run/IOpenable.dart';
import 'package:pip_services3_components/src/connect/ConnectionParams.dart';
import 'package:pip_services3_components/src/connect/ConnectionResolver.dart';
import 'package:pip_services3_components/src/auth/CredentialParams.dart';
import 'package:pip_services3_components/src/auth/CredentialResolver.dart';

class MyComponent implements IConfigurable, IReferenceable, IOpenable {
final _connectionResolver = ConnectionResolver();
final _credentialResolver = CredentialResolver();
bool _opened = false;

@override
void configure(ConfigParams config) {
_connectionResolver.configure(config);
_credentialResolver.configure(config);
}

@override
void setReferences(IReferences refs) {
_connectionResolver.setReferences(refs);
_credentialResolver.setReferences(refs);
}

// ...
@override
Future open(String? correlationId) async {
ConnectionParams? connection =
await _connectionResolver.resolve(correlationId);

CredentialParams? credential =
await _credentialResolver.lookup(correlationId);

if (connection != null && credential != null) {
String? host = connection.getHost();
int? port = connection.getPort();
String? user = credential.getUsername();
String? pass = credential.getPassword();
// ...
_opened = true;
}
}

@override
Future close(String? correlationId) {
// do closing
return Future.value();
}

@override
bool isOpen() {
return _opened;
}
}

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Example how to use caching and locking.
Here we assume that references are passed externally.
import 'package:pip_services3_commons/src/refer/Descriptor.dart';
import 'package:pip_services3_commons/src/refer/References.dart';
import 'package:pip_services3_commons/src/refer/IReferences.dart';
import 'package:pip_services3_commons/src/refer/IReferenceable.dart';
import 'package:pip_services3_components/src/lock/ILock.dart';
import 'package:pip_services3_components/src/lock/MemoryLock.dart';
import 'package:pip_services3_components/src/cache/ICache.dart';
import 'package:pip_services3_components/src/cache/MemoryCache.dart';

class MyComponent implements IReferenceable {
ICache? _cache;
ILock? _lock;

@override
void setReferences(IReferences refs) {
_cache =
refs.getOneRequired<ICache>(Descriptor('*', 'cache', '*', '*', '1.0'));
_lock =
refs.getOneRequired<ILock>(Descriptor('*', 'lock', '*', '*', '1.0'));
}

Future myMethod(String? correlationId, dynamic param1) async {
// First check cache for result
dynamic result = await _cache!.retrieve(correlationId, 'mykey');

// Lock..
await _lock!.acquireLock(correlationId, 'mykey', 1000, 1000);

// Do processing
// ...

// Store result to cache async
await _cache!.store(correlationId, 'mykey', result, 3600000);

// Release lock async
await _lock!.releaseLock(correlationId, 'mykey');
}
}

void main() async {
// Use the component
MyComponent myComponent = MyComponent();

myComponent.setReferences(References.fromTuples([
Descriptor('pip-services', 'cache', 'memory', 'default', '1.0'),
MemoryCache(),
Descriptor('pip-services', 'lock', 'memory', 'default', '1.0'),
MemoryLock(),
]));

await myComponent.myMethod(null, 'param1');
}
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If you need to create components using their locators (descriptors) implement
component factories similar to the example below.
import 'package:pip_services3_components/src/build/Factory.dart';
import 'package:pip_services3_commons/src/refer/Descriptor.dart';

class MyFactory extends Factory {
static Descriptor myComponentDescriptor =
Descriptor('myservice', 'mycomponent', 'default', '*', '1.0');

MyFactory() : super() {
registerAsType(MyFactory.myComponentDescriptor, MyComponent);
}
}

// Using the factory

MyFactory myFactory = MyFactory();

MyComponent1 myComponent1 = myFactory.create(
Descriptor('myservice', 'mycomponent', 'default', 'myComponent1', '1.0'));
MyComponent2 myComponent2 = myFactory.create(
Descriptor('myservice', 'mycomponent', 'default', 'myComponent2', '1.0'));
...
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Develop #
For development you shall install the following prerequisites:

Dart SDK 2
Visual Studio Code or another IDE of your choice
Docker

Install dependencies:
pub get
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Run automated tests:
pub run test
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Generate API documentation:
./docgen.ps1
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Before committing changes run dockerized build and test as:
./build.ps1
./test.ps1
./clear.ps1
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Contacts #
The library is created and maintained by Sergey Seroukhov and Levichev Dmitry.
The documentation is written by Egor Nuzhnykh, Alexey Dvoykin, Mark Makarychev, Levichev Dmitry.