func prechecks()

in reverse_replication/reverse-replication-runner.go [117:194]
68 lines of code
24 McCabe index (conditional complexity)

func prechecks() error {
	if projectId == "" {
		return fmt.Errorf("please specify a valid projectId")
	}
	if dataflowRegion == "" {
		return fmt.Errorf("please specify a valid dataflowRegion")
	}
	if jobNamePrefix == "" {
		return fmt.Errorf("please specify a non-empty jobNamePrefix")
	} else {
		// Capital letters not allowed in Dataflow job names.
		jobNamePrefix = strings.ToLower(jobNamePrefix)
	}
	if gcsPath == "" {
		return fmt.Errorf("please specify a non-empty gcsPath")
	} else if !strings.HasPrefix(gcsPath, "gs://") {
		return fmt.Errorf("please specify a valid GCS path for gcsPath, like gs://<>")
	}
	if changeStreamName == "" {
		return fmt.Errorf("please specify a valid changeStreamName")
	} else {
		changeStreamName = strings.ReplaceAll(changeStreamName, "-", "_")
	}
	if instanceId == "" {
		return fmt.Errorf("please specify a valid instanceId")
	}
	if dbName == "" {
		return fmt.Errorf("please specify a valid dbName")
	}
	if metadataInstance == "" {
		metadataInstance = instanceId
		fmt.Println("metadataInstance not provided, defaulting to target spanner instance id: ", metadataInstance)
	}
	if metadataDatabase == "" {
		metadataDatabase = "rev_repl_metadata"
		fmt.Println("metadataDatabase not provided, defaulting to: ", metadataDatabase)
	}

	if sourceShardsFilePath == "" {
		return fmt.Errorf("please specify a valid sourceShardsFilePath")
	} else if !strings.HasPrefix(sourceShardsFilePath, "gs://") {
		return fmt.Errorf("please specify a valid GCS path for sourceShardsFilePath, like gs://<>")
	}

	if sessionFilePath == "" {
		return fmt.Errorf("please specify a valid sessionFilePath")
	} else if !strings.HasPrefix(sessionFilePath, "gs://") {
		return fmt.Errorf("please specify a valid GCS path for sessionFilePath, like gs://<>")
	}

	if machineType == "" {
		machineType = "n2-standard-4"
		fmt.Println("machineType not provided, defaulting to: ", machineType)
	}

	if vpcHostProjectId == "" {
		vpcHostProjectId = projectId
	}

	if readerShardingCustomJarPath != "" && readerShardingCustomClassName == "" {
		return fmt.Errorf("When supplying readerShardingCustomJarPath value, the readerShardingCustomClassName should also be supplied ")
	}

	if readerShardingCustomClassName != "" && readerShardingCustomJarPath == "" {
		return fmt.Errorf("When supplying readerShardingCustomClassName value, the readerShardingCustomJarPath should also be supplied ")
	}

	if readerShardingCustomJarPath != "" && !strings.HasPrefix(readerShardingCustomJarPath, "gs://") {
		return fmt.Errorf("please specify a valid GCS path for readerShardingCustomJarPath, like gs://<>")
	}

	if spannerProjectId == "" {
		fmt.Println("Setting the Spanner Project Id to Dataflow project id: ", projectId)
		spannerProjectId = projectId
	}

	return nil
}