Lifecycle of a Plugin¶
Prerequisites¶
The following overview refers to Plugin
s, in reference to any new
Plugin
class developed with the SDK.
Overview¶
The lifecycle of a Plugin
in Designer can be broken down into two
different types of runs: 1. Workflow Run 2. Update Only
A workflow run is the simpler of the two, so lets start with that.
Workflow Run¶
When you hit the Run
button in Alteryx Designer, an instance of your
Plugin
class will be created for each of your tools on the canvas.
The Plugin
is constructed via it’s __init__
method, just like in
normal Python. An instance of a Provider
class will be given to the
plugin. Any resources required to read from/write to Designer can be
obtained via methods/properties on the Provider
.
In Alteryx Designer, input anchors can have one or many connections
(controlled via the AllowMultiple
flag in the tools XML definition).
If you have any input connections, the next stage in the lifecycle
consists of each of those input connections being opened, and data being
pushed to each one. From the Plugin
perspective, the
on_input_connection_opened
method will be called for each connection
that gets opened (the parameter it receives is the connection that was
opened), and then (typically, BEFORE the next connection is opened),
data packets will be streamed to the plugin. Receiving record packets
will cause the on_record_packet
method to be called. The parameter
that on_record_packet
receives is the connection that a new record
packet is available on.
Once all record packets for all connections have been received, the
Plugin
’s on_complete
method will be called in order to do any
cleanup.
If your Plugin
class does not have any input anchors, the lifecycle
is the same, however, on_input_connection_opened
, and
on_record_packet
never get called, since there are no
connections/received records. This means that any records that you wish
to output must be pushed during the on_complete
method (you
shouldn’t push them during __init__
, for reasons described below).
In order to push records to your Plugin
’s output anchors, they must
first be open
ed with metadata. This Metadata
object describes
the record schema for that output anchor (i.e. field names/types/etc.).
See this sequence diagram for a visual representation of this lifecycle:

Workflow Run Sequence Diagram¶
Update Only¶
Update only is a mode that runs in Designer any time: 1. A new tool is added to the canvas 2. Any tool on the canvas has a change in configuration (typically, via the UI/config pane).
The purpose of this run mode is to generate the metadata that each tool will output during the next time a workflow runs. This allows new tools on the canvas to know what columns it can operate on. The metadata that comes out of a tool typically depends on: 1. The incoming metadata 2. The configuration of the tool (via the UI)
In this mode, a subset of the Plugin
methods get called: 1.
__init__
2. on_input_connection_opened
Since the goal of an Update Only run is to build output metadata, the
__init__
or on_input_connection_opened
should run the open
method on any output anchors the tool has. Additionally, since
__init__
and on_input_connection_opened
run in update only mode,
care should be taken by a developer to perform the minimal amount of
processing in these methods, as a fast update only makes users happy :).
See the sequence diagram for a visual representation of this lifecycle:

Update Only Sequence Diagram¶