refactor(logcache-communication): replace the custom LogCacheClient with a simple LogCacheFetcher and build actual logcache.Client in another component

[geigerj0]

ℹ️ This PR is based on #2983 ℹ️

Problem

The current implementation of src/autoscaler/eventgenerator/client/log_cache_client.go has some aspects that could benefit from improvement to enhance readability and maintainability:

• builder like API which is not required

  app-autoscaler-release/src/autoscaler/eventgenerator/client/metric_client_factory.go

  Lines 38 to 57 in b7c34a8

  	c := NewLogCacheClient(logger, time.Now, conf.Aggregator.AggregatorExecuteInterval, envelopeProcessor, conf.MetricCollector.MetricCollectorURL)
  	if hasUAACreds(conf) {
  	uaaCreds := models.UAACreds{
  	URL: conf.MetricCollector.UAACreds.URL,
  	ClientID: conf.MetricCollector.UAACreds.ClientID,
  	ClientSecret: conf.MetricCollector.UAACreds.ClientSecret,
  	SkipSSLValidation: conf.MetricCollector.UAACreds.SkipSSLValidation,
  	}
  	c.SetUAACreds(uaaCreds)
  	} else {
  	tlsCerts := &models.TLSCerts{
  	KeyFile: conf.MetricCollector.TLSClientCerts.KeyFile,
  	CertFile: conf.MetricCollector.TLSClientCerts.CertFile,
  	CACertFile: conf.MetricCollector.TLSClientCerts.CACertFile,
  	}
  	tlsConfig, _ := tlsCerts.CreateClientConfig()
  	c.SetTLSConfig(tlsConfig)
  	}
  	c.Configure()

• building the actual Log Cache should be the responsibility of another component to make it easier testable:

  app-autoscaler-release/src/autoscaler/eventgenerator/client/log_cache_client.go

  Lines 242 to 254 in b7c34a8

  	func (c *LogCacheClient) Configure() {
  	var opts []logcache.ClientOption
  	if c.uaaCreds.IsEmpty() {
  	opts = append(opts, c.goLogCache.WithViaGRPC(c.grpc.WithTransportCredentials(credentials.NewTLS(c.TLSConfig))))
  	} else {
  	oauth2HTTPOpts := c.goLogCache.WithOauth2HTTPClient(c.getUaaHttpClient())
  	oauth2HTTPClient := c.goLogCache.NewOauth2HTTPClient(c.uaaCreds.URL, c.uaaCreds.ClientID, c.uaaCreds.ClientSecret, oauth2HTTPOpts)
  	opts = append(opts, c.goLogCache.WithHTTPClient(oauth2HTTPClient))
  	}
  	c.Client = c.goLogCache.NewClient(c.url, opts...)
  	}

• a lot of unnecessary getters and setters that can be replaced by building the actual Log Cache client with another component:

  app-autoscaler-release/src/autoscaler/eventgenerator/client/log_cache_client.go

  Lines 214 to 240 in b7c34a8

  	func (c *LogCacheClient) SetTLSConfig(tlsConfig *tls.Config) {
  	c.TLSConfig = tlsConfig
  	}
  	func (c *LogCacheClient) GetTlsConfig() *tls.Config {
  	return c.TLSConfig
  	}
  	func (c *LogCacheClient) SetUAACreds(uaaCreds models.UAACreds) {
  	c.uaaCreds = uaaCreds
  	}
  	func (c *LogCacheClient) GetUAACreds() models.UAACreds {
  	return c.uaaCreds
  	}
  	func (c *LogCacheClient) GetUrl() string {
  	return c.url
  	}
  	func (c *LogCacheClient) SetGoLogCache(goLogCache GoLogCache) {
  	c.goLogCache = goLogCache
  	}
  	func (c *LogCacheClient) SetGRPC(grpc GRPC) {
  	c.grpc = grpc
  	}

• a lot of unnecessary Log Cache client options that are not needed if the actual Log Cache client is created in another component:

  app-autoscaler-release/src/autoscaler/eventgenerator/client/log_cache_client.go

  Lines 80 to 86 in b7c34a8

  	goLogCache: GoLogCache{
  	NewClient: logcache.NewClient,
  	WithViaGRPC: logcache.WithViaGRPC,
  	WithHTTPClient: logcache.WithHTTPClient,
  	NewOauth2HTTPClient: logcache.NewOauth2HTTPClient,
  	WithOauth2HTTPClient: logcache.WithOauth2HTTPClient,
  	},

Solution

• replace the whole client/ package with a rewrite in metric/ package
• introduce a fetcher that has the only responsibility of wrapping the Log Cache client and providing a slim interface to query metrics from Log Cache using the internal client
• introduce factory that takes care of the actual Log Cache client creation and passes it to a new fetcher

[bonzofenix]

lgtm

[sonarqubecloud]

Quality Gate failed

Failed conditions
13.3% Duplication on New Code (required ≤ 3%)

See analysis details on SonarCloud