logging.service.ts

import { Injectable, Optional } from "@angular/core";

import { Severity } from "./severity.enum";
import { IConfiguration, LoggingConfig } from "@angularlicious/configuration";
import { ConfigurationService } from "@angularlicious/configuration";
import { LogEntry } from "./log-entry";
import { Subject, ReplaySubject } from "rxjs";
import { ILogEntry } from "./i-log-entry";
import { ILoggingConfig } from "./config/i-logging-config";

@Injectable()
export class LoggingService {
  serviceName = "LoggingService";
  source: string;
  severity: Severity;
  message: string;
  timestamp: Date;
  applicationName = "application";
  version = "0.0.0";
  isProduction: boolean;
  config: LoggingConfig;

  logEntries$: Subject<ILogEntry> = new ReplaySubject<ILogEntry>(1);

  constructor(@Optional() public configService: ConfigurationService) {
    this.timestamp = new Date(Date.now());
    this.log(
      this.serviceName,
      Severity.Information,
      `Starting logging service at: ${this.timestamp}`
    );

    if (configService) {
      this.configService.settings$.subscribe(settings =>
        this.handleSettings(settings)
      );
    }
  }

  handleSettings(settings: IConfiguration) {
    this.config = settings as LoggingConfig;
    this.applicationName =
      this.config && this.config.loggingConfig.applicationName
        ? this.config.loggingConfig.applicationName
        : "application";
    this.version =
      this.config && this.config.loggingConfig.version
        ? this.config.loggingConfig.version
        : "0.0.0";
    this.isProduction =
      this.config && this.config.loggingConfig.isProduction
        ? this.config.loggingConfig.isProduction
        : false;
  }

  log(source: string, severity: Severity, message: string, tags?: string[]) {
    this.source = `${this.applicationName}.${source}`;
    this.severity = severity;
    this.message = message;
    this.timestamp = new Date(Date.now());

    const logEntry = new LogEntry(
      this.applicationName,
      this.source,
      this.severity,
      this.message,
      tags
    );
    this.logEntries$.next(logEntry);
  }
}