model

Documentation

Index

• type Command
• type Document
• type Event
• type EventMeta
• type EventStoreQuery
• type LogEntry

Types

type Command

type Command struct {
	// AggregateID is the ID of aggregate the document is for.
	AggregateID int8 `json:"aggregateID,omitempty"`

	// EventAction is the action for which the command is being produced.
	EventAction string `json:"eventAction,omitempty"`

	// ServiceAction is the service-action for which the command is being produced.
	ServiceAction string `json:"serviceAction,omitempty"`

	// Data is the data required for invoking the command.
	Data []byte `json:"data,omitempty"`
}

Command can be used to invoke a procedure in another service.

type Document

type Document struct {
	// AggregateID is the ID of aggregate the document is for.
	AggregateID int8 `json:"aggregateID,omitempty"`

	// EventAction is the action corresponding to which the document was produced.
	EventAction string `json:"eventAction,omitempty"`

	// ServiceAction is the service-specific Action for the event.
	// For example, "insert" is EventAction, but "insertUser" is ServiceAction,
	// informing service that a user was inserted.
	ServiceAction string `json:"serviceAction,omitempty"`

	// CorrelationID can be used to "link" documents, such as if two documents
	// are somehow related (for example, when implementing batching).
	// Including CorrelationID will result in inclusion of this ID in any
	// responses generated as per result of event's processing.
	CorrelationID uuuid.UUID `json:"correlationID,omitempty"`

	// Error is the error occurred while processing the Input.
	// Convert errors to strings, this is just an indication that
	// something went wrong, so we can signal/display-error to end-
	// user. Blank Error-string means everything was fine.
	Error string `json:"error,omitempty"`

	// ErrorCode can be used to identify type of error.
	ErrorCode int16 `json:"errorCode,omitempty"`

	// Input is the data that was being processed.
	// Use this to provide context of whatever data was attempted to be processed.
	Input []byte `json:"input,omitempty"`

	// Result is the result after an input was processed.
	// This is some data returned by processing (such as database results) etc.
	Result []byte `json:"result,omitempty"`

	// Topic is the topic on which Kafka producer should produce this message.
	// This field will not be included as part of the document, and is only
	// for referencing purposes for producer.
	Topic string `json:"topic,omitempty"`

	// UUID is the V4-UUID Document-Identifier.
	// This can be same as service-query UUID, and can be used for identification puposes.
	UUID uuuid.UUID `json:"uuid,omitempty"`
}

Document can be used to transfer data between services.

type Event

type Event struct {
	// AggregateID is the ID of aggregate responsible for consuming event.
	AggregateID int8 `cql:"aggregate_id,omitempty" json:"aggregateID,omitempty"`

	// EventAction is the core-action being performed by event.
	// For example, "insert" is EventAction, but "insertUser" is ServiceAction,
	// informing service that a user was inserted.
	EventAction string `cql:"event_action,omitempty" json:"eventAction,omitempty"`

	// ServiceAction is the service-specific Action for the event.
	// For example, "insert" is EventAction, but "insertUser" is ServiceAction,
	// informing service that a user was inserted.
	ServiceAction string `cql:"service_action,omitempty" json:"serviceAction,omitempty"`

	// CorrelationID can be used to "link" events, such as if an event was result of another event.
	// The related events should have cmmon CorrelationIDs, but unique UUIDs.
	// Including CorrelationID will result in inclusion of this ID in any
	// responses generated as per result of event's processing.
	CorrelationID uuuid.UUID `cql:"correlation_id,omitempty" json:"correlationID,omitempty"`

	// Data is the data contained by event.
	Data []byte `cql:"data,omitempty" json:"data,omitempty"`

	// NanoTime is the time in nanoseconds since Unix-epoch to when the event was generated.
	NanoTime int64 `cql:"nano_time,omitempty" json:"nanoTime,omitempty"`

	// UserUUID is the V4-UUID of the user who generated the event.
	UserUUID uuuid.UUID `cql:"user_uuid,omitempty" json:"userUUID,omitempty"`

	// UUID is the V4-UUID unique-indentifier for event.
	UUID uuuid.UUID `cql:"uuid,omitempty" json:"uuid,omitempty"`

	// Version is the version for events as processed for aggregate-projection.
	// This is incremented by the aggregate itself each time it updates its
	// projection.
	Version int64 `cql:"version,omitempty" json:"version,omitempty"`

	// Year bucket is the year in which the event was generated.
	// This is used as the partitioning key.
	YearBucket int16 `cql:"year_bucket,omitempty" json:"yearBucket,omitempty"`
}

Event refers to any interaction with the system, such as inserting or retrieving any data.

type EventMeta

type EventMeta struct {
	// AggregateID corresponds to AggregateID in
	// event-store and ID in aggregate-projection.
	AggregateID int8 `cql:"aggregate_id,omitempty" json:"aggregateID,omitempty"`
	// AggregateVersion tracks the version to be used
	// by new events for that aggregate.
	AggregateVersion int64 `cql:"aggregate_version,omitempty" json:"aggregateVersion,omitempty"`
	// PartitionKey is the partitioning key for events_meta table.
	PartitionKey int8 `cql:"partition_key,omitempty" json:"partitionKey,omitempty"`
}

EventMeta contains the information about hydrating Aggregate-Projections. The AggregateVersion tracks the version to be used by new events for that aggregate. This difference between the aggregate-projection version and AggregateVersion gives us the versions of the events yet to be applied to the aggregate projection.

type EventStoreQuery

type EventStoreQuery struct {
	// AggregateID is the id for aggregate whose events are to be fetched
	AggregateID int8 `json:"aggregateID,omitempty"`

	// AggregateVersion is the highest version of events that have been
	// already fetched by the aggregate. The event-store will be queried
	// for events greater than this version.
	AggregateVersion int64 `json:"aggregateVersion,omitempty"`

	// CorrelationID can be used to "identify" responses, such as checking
	// if the response is for some particular request.
	// Including CorrelationID will result in inclusion of this ID in any
	// responses generated as per result of event's processing.
	CorrelationID uuuid.UUID `json:"correlationID,omitempty"`

	// EventAction is the core-action being performed by event.
	// For example, "insert" is EventAction, but "insertUser" is ServiceAction,
	// informing service that a user was inserted.
	EventAction string `json:"eventAction,omitempty"`

	// ServiceAction is the service-specific Action for the event.
	// For example, "insert" is EventAction, but "insertUser" is ServiceAction,
	// informing service that a user was inserted.
	ServiceAction string `json:"serviceAction,omitempty"`

	// YearBucket is the partition-key for Event-Table.
	YearBucket int16 `json:"yearBucket,omitempty"`

	// UUID is the V4-UUID Query-Identifier.
	// This can be used to "identify" responses.
	UUID uuuid.UUID `json:"uuid,omitempty"`
}

EventStoreQuery can be used to fetch later events than the specified version.

type LogEntry

type LogEntry struct {
	// Description of what happened, can also be an error description.
	Description string `json:"description,omitempty"`
	// ErrorCode is just to inform the kind or classification of error.
	ErrorCode int `json:"errorCode,omitempty"`
	// Level is the severity-level, that is, info, warning, or error.
	Level string `json:"level,omitempty"`
	// EventAction is the action being performed by event corresponding to this log.
	EventAction string `json:"eventAction,omitempty"`
	// EventAction is the service-level action being performed by event
	// corresponding to this log.
	ServiceAction string `json:"serviceAction,omitempty"`
	// ServiceName is the service associated with the log.
	ServiceName string `json:"serviceName,omitempty"`
}

LogEntry describes the "currently-happening" event. Use this to show if everything is going as intended, or reasons for why not.