Dashboard Metadata and Rendering
This page documents:
- The fields written to notebook documents (
.ipynbfiles) by thejupyter-incubator/dashboardsextension - The interpretation of these fields used in
jupyter-incubator/dashboards,jupyter-incubator/dashboards_bundlers, andjupyter-incubator/dashboards_serverto render a notebook as a dashboard.
The v0 spec is currently in use across the incubating dashboard projects. It evolved as the projects evolved and deserves revision based on lessons learned. We are drafting v1 of the spec in order to remove old monikers, make room for future improvements (e.g., aligning with a layout specification adopted by the community), and progress the incubating projects toward graduation.
The following snippet of JSON shows the fields read and written by the dashboard projects. A more formal JSON schema appears later in this document.
{
"metadata": { // notebook level metadata
"extensions": { // per enhancement proposal, to avoid future notebook conflicts
"jupyter_dashboards" : { // per enhancement proposal, pypi package name
"version": 1, // spec version
"activeView": "<str:views key>", // initial view to render
"views": {
"<str: tool defined ID 1>": { // tool-assigned, unique layout ID
"name": "<str>", // user-assigned, unique human readable name
"type": "grid", // layout algorithm to use (grid in this example view)
"cellMargin": <uint:10>, // margin between cells in pixels
"cellHeight": <uint:20>, // height in pixels of a logical row
"numColumns": <uint:12> // total number of logical columns
},
"<str: tool defined ID 2>": { // tool-assigned, unique layout ID
"name": "<str>", // user-assigned, unique human readable name
"type": "report" // layout algorithm to use (report in this example view)
}
}
}
}
},
"cells": [
{
"metadata": {
"extensions": {
"jupyter_dashboards": {
"version": 1, // spec version
"views": {
"<str: tool defined ID 1>": { // if present, means the grid layout algorithm has processed this cell
"hidden": <bool:false>, // if cell output+widget are visible in the layout
"row": <uint:0>, // logical row position
"col": <uint:0>, // logical column position
"width": <uint:6>, // logical width
"height": <uint:2> // logical height
},
"<str: tool defined ID 2>": { // if present, means the report layout algorithm has processed this cell
"hidden": <bool:false> // if cell output+widget are visible in the layout
}
}
}
}
}
}
]
}
A dashboard renderer is responsible for reading the notebook document, executing cell inputs, and placing cell outputs in a dashboard view. Cell outputs include anything that Jupyter Notebook 4.x renders in the cell output subarea or cell widget subarea in response to kernel messages or client-side events. A dashboard view defines how cell outputs are positioned and sized with respect to one another according to a particular layout algorithm.
The notebook can have multiple dashboard view associated with it in the metadata.extensions.jupyter_dashboards.views field. This specification defines two view types, report and grid, that dictate how a renderer positions and sizes cells on the page.
The report type stacks cell outputs top-to-bottom, hiding cells marked as hidden. The height of each cell varies automatically to contain its content. The width of all cells is equivalent and set by the renderer.
To display a metadata.jupyter_dashboards.views[view_id] with type report properly, the renderer:
- Must execute cell inputs in the order defined by the notebook
cellsarray. - Must not render nor reserve display space for cells that have
metadata.extensions.jupyter_dashboards.views[<view id>].hidden=true. - Must arrange cell outputs top-to-bottom in order of execution (i.e., stacked vertically).
- Must space cell outputs vertically so that they do overlap at any time (e.g., a plot in the top-most cell should not overlap Markdown in the next down cell nor any cell below that).
- Should allow interactive widgets in cell outputs to render content that does overlap other cells (e.g., popups).
- Should wrap cell outputs that have variable length content (e.g., text) at a renderer-determined width (e.g., browser width, responsive container element, fixed width).
- Should include a fixed amount of vertical whitespace between cell outputs.
The grid type positions cells in a grid with infinitely many rows and a fixed number of columns. The width and height of each cell is expressed in terms of these rows and columns. The physical height of each row is a fixed value while the width of each column is set by the renderer.
Consider a view with tool-assigned ID view_id and type grid defined in the notebook-level metadata (i.e., metadata.extensions.jupyter_dashboards.views[view_id]). Let view be a reference to this notebook-level object. Let cell_view be a reference to any cell-level object keyed by the same view_id. To properly display this view, the renderer:
- Must execute cell inputs in the order defined by the notebook
cellsarray. - Must not render nor reserve display space for cells that have
cell_view.hidden=true. - Must define a logical grid with an unbounded number of rows and
view.numColumnscolumns per row. - Must define a screen viewport with infinite height and a renderer-determined width (e.g., browser width, responsive container element, fixed width).
- Must map the grid origin (row zero, column zero) to the top left corner of the viewport.
- Must allocate
view.cellHeightpixels of space in the viewport to each grid row. - Must allocate a fixed, renderer-determined number of pixels in the viewport to each grid column.
- Must place a cell's outputs in the
cell_view.rowandcell_view.colslot in the grid. - Must allocate
cell_view.widthcolumns andcell_view.heightrows of space in the grid for a cell's output. - Must separate each slot in the grid on the screen by
view.cellMarginpixels. - May clip, scale, wrap, or let overflow cell output that is bigger than its allocated space on the screen.
When presented with a document having no metadata.extensions.jupyter_dashboards.views at the notebook-level, a renderer:
- Should process the document as if it defines a
reportview with all cells visible. - May persist the implicit all-cells-visible report view to the document.
When processing cells that have no view ID corresponding to the current view being displayed, a display-only renderer with no authoring capability should treat such cells as hidden. A renderer with layout authoring capability:
- Should make a best effort attempt at determining the properties for the cell in the view based on the content of the cell.
- e.g., Set
cell_view.hidden=falseif the cell produces no output. - e.g., Set
cell_view.row,cell_view.col,cell_view.width, andcell_view.heightto values that do not overlap other cells in a grid layout.
- e.g., Set
- Should immediately persist such default values into the document to avoid inferring them again in the future.
- Must allow the user to override the computed default values.
The following schema expresses the dashboard layout specification as additions to the existing notebook format v4 schema. The schema below omits any untouched portions of the notebook schema for brevity.
{
"$schema": "http://json-schema.org/draft-04/schema#",
"description": "IPython Notebook v4.0 JSON schema plus layouts.",
"properties": {
"metadata": {
"properties": {
"extensions": {
"description": "Notebook-level namespace for extensions",
"type": "object",
"additionalProperties": true,
"properties": {
"jupyter_dashboards": {
"description": "Namespace for jupyter_dashboards notebook metadata",
"type": "object",
"additionalProperties": true,
"properties": {
"version": {
"description": "Version of the metadata spec",
"type": "integer",
"minimum": 1,
"maximum": 1
},
"activeView": {
"description": "ID of the view that should render by default",
"type": "string"
},
"views": {
"description": "View definition",
"type": "object",
"additionalProperties": false,
"patternProperties": {
"^[a-zA-Z0-9_-]+$": {
"type": "object",
"oneOf": [{
"$ref": "#definitions / jupyter_dashboards / notebook_grid_view "
}, {
"$ref": "#definitions / jupyter_dashboards / notebook_report_view "
}]
}
}
}
}
}
}
}
}
}
},
"definitions": {
"raw_cell": {
"properties": {
"metadata": {
"properties": {
"extensions": {
"description": "Cell-level namespace for extensions",
"type": "object",
"additionalProperties": true,
"properties": {
"jupyter_dashboards": {"$ref": "#definitions/jupyter_dashboards/cell_view"}
}
}
}
}
}
},
"markdown_cell": {
"properties": {
"metadata": {
"properties": {
"extensions": {
"description": "Cell-level namespace for extensions",
"type": "object",
"additionalProperties": true,
"properties": {
"jupyter_dashboards": {"$ref": "#definitions/jupyter_dashboards/cell_view"}
}
}
}
}
}
},
"code_cell": {
"properties": {
"metadata": {
"properties": {
"extensions": {
"description": "Cell-level namespace for extensions",
"type": "object",
"additionalProperties": true,
"properties": {
"jupyter_dashboards": {"$ref": "#definitions/jupyter_dashboards/cell_view"}
}
}
}
}
}
},
"jupyter_dashboards": {
"notebook_grid_view": {
"description": "Grid view definition",
"type": "object",
"additionalProperties": true,
"properties": {
"name": {
"description": "Human readable name of the view",
"type": "string"
},
"type": {
"description": "Grid view type",
"enum": ["grid"]
},
"cellMargin": {
"description": "Margin between cells in pixels",
"type": "integer",
"minimum": 0
},
"cellHeight": {
"description": "Height of a logical row in pixels",
"type": "integer",
"minimum": 0
},
"numColumns": {
"description": "Total number of logical columns",
"type": "integer",
"minimum": 1
}
}
},
"notebook_report_view": {
"description": "Report view definition",
"type": "object",
"additionalProperties": true,
"properties": {
"name": {
"description": "Human readable name of the view",
"type": "string"
},
"type": {
"description": "Report view type",
"enum": ["report"]
}
}
},
"cell_view": {
"description": "Namespace for jupyter_dashboards cell metadata",
"type": "object",
"additionalProperties": true,
"properties": {
"version": {
"description": "Version of the metadata spec",
"type": "integer",
"minimum": 1,
"maximum": 1
},
"views": {
"description": "Layout information for cell in view",
"type": "object",
"additionalProperties": false,
"patternProperties": {
"^[a-zA-Z0-9_-]+$": {
"type": "object",
"oneOf": [{
"$ref": "#definitions / jupyter_dashboards / cell_grid_view "
}, {
"$ref": "#definitions / jupyter_dashboards / cell_report_view "
}]
}
}
}
}
},
"cell_grid_view": {
"description": "Grid view metadata for a cell",
"type": "object",
"additionalProperties": true,
"properties": {
"hidden": {
"description": "True if cell is hidden in the view",
"type": "boolean"
},
"row": {
"description": "Logical grid row",
"type": "integer",
"minimum": 0
},
"col": {
"description": "Logical grid column",
"type": "integer",
"minimum": 0
},
"width": {
"description": "Width in logical columns",
"type": "integer",
"minimum": 1
},
"height": {
"description": "Height in logical rows",
"type": "integer",
"minimum": 1
}
}
},
"cell_report_view": {
"description": "Report view metadata for a cell",
"type": "object",
"additionalProperties": true,
"properties": {
"hidden": {
"description": "True if cell is hidden in the view",
"type": "boolean"
}
}
}
}
}
}
The following snippet of JSON shows the fields read and written by the dashboard projects.
{
"metadata": {
"urth": { // original project codename
"dashboard": { // dashboard tool metadata section
"layout": "grid|report", // algorithm to use for layout, grid if unspecified
"cellMargin": <uint:10>, // in grid layout, margin between cells in pixels
"defaultCellHeight": <uint:20>, // in grid layout, height in pixels of a logical row
"maxColumns": <uint:12> // in grid layout, total number of logical columns
}
}
},
"cells": [
{
"metadata": {
"urth": {
"dashboard": {
"hidden": <bool:false>, // if the cell output+widget area are visible in the layout
"layout" : {
"row": <uint:0>, // in grid layout, logical row position
"col": <uint:0>, // in grid layout, logical column position
"width": <uint:6>, // in grid layout, logical width
"height": <uint:2> // in grid layout, logical height
}
}
}
}
}
]
}
A dashboard renderer is responsible for reading the notebook document, executing cell inputs, and placing cell outputs in a dashboard layout. Cell outputs include anything that Jupyter Notebook 4.x renders in the cell output subarea or cell widget subarea in response to kernel messages or client-side events. A dashboard layout defines how cell outputs are positioned and sized with respect to one another.
The notebook can have one and only one layout associated with it indicated in the metadata.urth.dashboard.layout field. There are two defined layout types, report and grid, described in the sections below.
The report layout stacks cell outputs top-to-bottom, hiding cells that are marked as hidden. The height of each cell varies sizes to contain its content. The width of all cells is equivalent and set by the renderer.
To show a proper report layout, the renderer:
- Must execute cell inputs in the order defined by the notebook
cellsarray. - Must not render nor reserve space for cells that have
urth.dashboard.hidden=true. - Must arrange cell outputs top-to-bottom in order of execution (i.e., stacked vertically).
- Must space cell outputs vertically so that they do overlap at any time (e.g., a plot in the top-most cell should not overlap Markdown in the next down cell nor any cell below that).
- Should allow interactive widgets in cell outputs to render content that does overlap other cells (e.g., popups).
- Should wrap cell outputs that have variable length content (e.g., text) at a renderer-determined width (e.g., browser width, responsive container element, fixed width).
- Should include a fixed amount of vertical whitespace between cell outputs.
The grid layout positions cells in a grid of infinitely many rows and a fixed number of columns. The width and height of each cell is expressed in terms of these rows and columns. The physical height of each row is a fixed value while the width of each column is set by the renderer.
The renderer:
- Must execute cell inputs in the order defined by the notebook
cellsarray. - Must not render nor reserve space for cells that have
urth.dashboard.hidden=true. - Must define a logical grid with an unbounded number of rows and
urth.dashboard.maxColumnscolumns per row. - Must define a screen viewport with infinite height and a renderer-determined width (e.g., browser width, responsive container element, fixed width).
- Must map the grid origin (row zero, column zero) to the top left corner of the viewport.
- Must allocate
urth.dashboard.defaultCellHeightpixels of space in the viewport to each grid row. - Must allocate a fixed, renderer-determined number of pixels in the viewport to each grid column.
- Must place a cell's outputs in the
urth.dashboard.rowandurth.dashboard.colslot in the grid. - Must allocate
urth.dashboard.widthcolumns andurth.dashboard.heightrows of space in the grid for a cell's output. - Must separate each slot in the grid on the screen by
urth.dashboard.cellMarginpixels. - May clip, scale, wrap, or let overflow cell output that is bigger than its allocated space on the screen.