func newCloudWatchLogsClient()

in cloudwatch/cloudwatch.go [238:313]
67 lines of code
13 McCabe index (conditional complexity)

func newCloudWatchLogsClient(config OutputPluginConfig) (*cloudwatchlogs.CloudWatchLogs, error) {
	customResolverFn := func(service, region string, optFns ...func(*endpoints.Options)) (endpoints.ResolvedEndpoint, error) {
		if service == endpoints.LogsServiceID && config.CWEndpoint != "" {
			return endpoints.ResolvedEndpoint{
				URL: config.CWEndpoint,
			}, nil
		} else if service == endpoints.StsServiceID && config.STSEndpoint != "" {
			return endpoints.ResolvedEndpoint{
				URL: config.STSEndpoint,
			}, nil
		}
		return endpoints.DefaultResolver().EndpointFor(service, region, optFns...)
	}

	// Fetch base credentials
	baseConfig := &aws.Config{
		Region:                        aws.String(config.Region),
		EndpointResolver:              endpoints.ResolverFunc(customResolverFn),
		CredentialsChainVerboseErrors: aws.Bool(true),
	}

	if config.CredsEndpoint != "" {
		creds := endpointcreds.NewCredentialsClient(*baseConfig, request.Handlers{}, config.CredsEndpoint,
			func(provider *endpointcreds.Provider) {
				provider.ExpiryWindow = 5 * time.Minute
			})
		baseConfig.Credentials = creds
	}

	sess, err := session.NewSession(baseConfig)
	if err != nil {
		return nil, err
	}

	var svcSess = sess
	var svcConfig = baseConfig
	eksRole := os.Getenv("EKS_POD_EXECUTION_ROLE")
	if eksRole != "" {
		logrus.Debugf("[cloudwatch %d] Fetching EKS pod credentials.\n", config.PluginInstanceID)
		eksConfig := &aws.Config{}
		creds := stscreds.NewCredentials(svcSess, eksRole)
		eksConfig.Credentials = creds
		eksConfig.Region = aws.String(config.Region)
		svcConfig = eksConfig

		svcSess, err = session.NewSession(svcConfig)
		if err != nil {
			return nil, err
		}
	}

	if config.RoleARN != "" {
		logrus.Debugf("[cloudwatch %d] Fetching credentials for %s\n", config.PluginInstanceID, config.RoleARN)
		stsConfig := &aws.Config{}
		creds := stscreds.NewCredentials(svcSess, config.RoleARN, func(p *stscreds.AssumeRoleProvider) {
			if config.ExternalID != "" {
				p.ExternalID = aws.String(config.ExternalID)
			}
		})
		stsConfig.Credentials = creds
		stsConfig.Region = aws.String(config.Region)
		svcConfig = stsConfig

		svcSess, err = session.NewSession(svcConfig)
		if err != nil {
			return nil, err
		}
	}

	client := cloudwatchlogs.New(svcSess, svcConfig)
	client.Handlers.Build.PushBackNamed(customUserAgentHandler(config))
	if config.LogFormat != "" {
		client.Handlers.Build.PushBackNamed(LogFormatHandler(config.LogFormat))
	}
	return client, nil
}