Crate exar_net

Exar DB's TCP protocol

This module defines the TCP protocol used by Exar DB.

Protocol messages

The protocol is text-based and uses line-separated messages, each message consists of tab-separated values.

Connect

Message used to initialize a connection to Exar DB.

Connect    collection    [username]    [password]

• The 1st field is the string Connect.
• The 2nd field is the collection name.
• The 3rd field is the authentication username (optional).
• The 4th field is the authentication password (optional).

Connected

Message used to acknowledge a successful connection.

Connected

• A single field containing the string Connected.

Publish

Message used to publish an event into a collection.

It can be used only after a successful connection has been established.

Publish    tag1 tag2    timestamp    event_data

• The 1st field is the string Publish.
• The 2nd field is a space-separated list of tags, the event must contain at least one tag.
• The 3rd field is the event timestamp (in ms), if set to 0 the timestamp will be set by the event logger.
• The 4th field is the event data/payload, it can contain tabs (\t) but new-lines (\n) must be escaped.

Published

Message used to acknowledge a successfully published event.

Published    event_id

• The 1st field is the string Published.
• The 2nd field is the id (or sequence number) of the event that has been published.

Subscribe

Message used to subscribe to an event stream.

It can be used only after a successful connection has been established.

Subscribe    live    offset    limit    [tag1]

• The 1st field is the string Subscribe.
• The 2nd field is a boolean specifying wether to keep the subscription listening to real-time events.
• The 3rd field is the query offset.
• The 4th field is the maximum number of events to consume, if set to 0 a limit is not set.
• The 5th field is the tag the events must contain (optional).

Subscribed

Message used to acknowledge a successful subscription.

Subscribed

• A single field containing the string Subscribed.

Event

Message containing an event.

It is received after a successful subscription.

Event    event_id    tag1 tag2    timestamp    event_data

• The 1st field is the string Event.
• The 2nd field is the id (or sequence number) of the event.
• The 3rd field is a space-separated list of event tags.
• The 4th field is the event timestamp (in ms).
• The 5th field is the event data/payload.

EndOfEventStream

Message signaling the end of an event stream.

It is received after a Subscribed or a list of Events.

EndOfEventStream

• A single field containing the string EndOfEventStream.

Error

Message containing an error.

It can be received after a Connect, Publish, Subscribe, or during an event stream.

Error    type    [subtype]    description

• The 1st field is the string Error.
• The 2nd field is the type of the error, possible values are: AuthenticationError, ConnectionError, EventStreamError, IoError, ParseError, SubscriptionError, ValidationError.
• The 3rd field is the sub-type of the error (optional), possible values are: Empty or Closed if the error type is EventStreamError, ParseError or MissingField if the error type is ParseError, or a stringified value of std::io::ErrorKind if the error type is IoError.
• The 4th field is the error message/description.

Structs

TcpMessageStream	A bidiectional TCP message stream.
TcpMessages	An iterator over the messages received on a stream.

Enums

TcpMessage

A list specifying categories of TCP message.

Traits

TryClone