Module plugin 

The plugin SDK: implement one of Source, Format or Destination and call the matching serve_* function from main. The SDK owns stdin/stdout, the handshake, framing, request ids, error replies and panics.

Formats and destinations declare their options (options()) and add any rule a declaration can’t express (validate()). The SDK checks a config block against both on validate and before every write and deliver, so plugin code only sees options that passed.

• Logging: use the log crate (log::info!, log::warn!), or [log] for a message with fields; the SDK sends them to core as log messages. The plugin’s own records keep their level; its dependencies’ are shown only with -v. Long requests may report progress.
• Errors: return a PluginError to give core the problem’s kind and code; any other error is sent as a plain message.
• Cancellation: stdin is read on a background thread while a request runs. On cancel (or when core goes away) cancelled turns true and the hook set with on_cancel runs, e.g. to cancel a query on the server.

Structs

About

Identity reported in the handshake.

Delivery

A destination deliver request.

DeliveryFile

One file to deliver: the local copy in target/run/ and its rendered remote path, if any.

Input

The frames core sends, read on a background thread (see [read_stdin]).

Loaded

The outcome of Source::load.

PluginError

An error with its kind and, optionally, a code. The SDK namespaces the code by the plugin (host-key-mismatch is sent as sftp/host-key-mismatch).

ResultSet

One incoming result set, streamed from core.

ResultSets

Hands a format plugin its result sets one at a time, in order.

WriteRequest

A format write request.

Enums

ErrorKind

What kind of problem a PluginError is (the kinds of DRE’s error-code registry).

Plugin

One of the plugins a package’s executable serves (see serve_package).

Traits

Destination

Format

ResultSink

Where a source pushes the outcome of execute: either no_result, or begin followed by any number of batch calls.

Source

Functions

cancelled

Whether core has cancelled the request running now. Long loops check it between steps.

conn_bool

Read a flag that may be written as a boolean or a string.

conn_required

Read a required string field from a connection map.

conn_str

Read a string field from a connection map.

log

Send a log message to core.

log_fields

Send a log message to core, with structured fields (never secrets).

on_cancel

Run hook when core cancels a request, on the stdin reader’s thread, while the request is still running on the main one (e.g. ask the server to cancel the query). Replaces any hook set before. The request then fails, and the SDK replies with kind cancelled.

progress

Tell core how far a long request has got; it shows the latest.

serve_destination

serve_format

serve_package

Serve every plugin of a package from one executable. Core’s hello names the plugin it wants; without one, the first is served.

serve_source

Type Aliases

Error

Result