Adding helpers that setup databricks notebook (#43)

Adding helpers that setup databricks notebook
---------

Co-authored-by: Zac Davies <[email protected]>

DESCRIPTION

@@ -33,6 +33,7 @@ Imports:
 Suggests: 
     testthat (>= 3.0.0),
     htmltools,
+    htmlwidgets,
     knitr,
     magick,
     rmarkdown,

NAMESPACE

@@ -124,6 +124,7 @@ export(get_and_start_cluster)
 export(get_and_start_warehouse)
 export(get_latest_dbr)
 export(git_source)
+export(in_databricks_nb)
 export(init_script_info)
 export(is.access_control_req_group)
 export(is.access_control_req_user)
@@ -168,7 +169,9 @@ export(lib_pypi)
 export(lib_whl)
 export(libraries)
 export(new_cluster)
+export(notebook_enable_htmlwidgets)
 export(notebook_task)
+export(notebook_use_posit_repo)
 export(open_workspace)
 export(pipeline_task)
 export(python_wheel_task)

R/brickster.R

@@ -0,0 +1 @@
+utils::globalVariables(c("displayHTML"))

R/notebook-helpers.R

@@ -0,0 +1,91 @@
+#' Detect if running within Databricks Notebook
+#'
+#' @details
+#' R sessions on Databricks can be detected via various environment variables
+#' and directories.
+#'
+#' @return Boolean
+#' @export
+in_databricks_nb <- function() {
+  ("/databricks/spark/R/lib"  %in% .libPaths()) &&
+    exists("DATABRICKS_GUID", envir = .GlobalEnv)
+}
+
+#' Setup Databricks Notebook with Posit Package Manager
+#'
+#' @details
+#' Databricks notebooks default repo for package installation is CRAN.
+#' CRAN doesn't provide pre-compiled binaries for linux and this results in
+#' packages taking longer than desired.
+#'
+#' This function can be called within a Databricks notebook to easily switch to
+#' Posit and retrieve pre-compiled binaries.
+#'
+#' This function will behave correctly across different Databricks Runtimes,
+#' even when the underlying linux version changes.
+#'
+#' @export
+notebook_use_posit_repo <- function() {
+  if (in_databricks_nb()) {
+    agent <- sprintf("R/%s R (%s)", getRversion(), paste(getRversion(), R.version["platform"], R.version["arch"], R.version["os"]))
+    codename <- system("lsb_release -c --short", intern = T)
+    mirror <- paste0("https://packagemanager.posit.co/cran/__linux__/", codename, "/latest")
+    options(
+      HTTPUserAgent = agent,
+      repos = c(POSIT = mirror, getOption("repos"))
+    )
+  }
+}
+
+#' Enable htmlwidgets in Databricks Notebook
+#'
+#' @details
+#' Databricks notebooks by default don't currently support htmlwidgets.
+#' This behaviour can be corrected by:
+#'  - adjusting the print method in htmltools
+#'  - installing pandoc
+#'
+#' This is a invasive method to correct the behaviour as htmltools isn't
+#' flexible to adjust via the `viewer` option directly.
+#'
+#' It only runs within a Databricks notebook cell.
+#'
+#' The height can be adjusted without running the function again by using the
+#' `db_htmlwidget_height` option (e.g. `options(db_htmlwidget_height = 300)`).
+#'
+#'
+#' @param height Measurement passed to height of htmlwidget. This overrides
+#' existing values that may often be `NULL` to ensure the height is correctly
+#' displayed within the iframe of notebook results cells (via `displayHTML()`).
+#' Default is 450.
+#'
+#' @export
+#'
+#' @examples
+#' notebook_enable_htmlwidgets()
+#' # set default height to 800px
+#' notebook_enable_htmlwidgets(height = 800)
+notebook_enable_htmlwidgets <- function(height = 450) {
+  if (in_databricks_nb()) {
+
+    # new option to control default widget height, default is 450px
+    options(db_htmlwidget_height = height)
+
+    system("apt-get --yes install pandoc", intern = T)
+    if (!base::require("htmlwidgets")) {
+      utils::install.packages("htmlwidgets")
+    }
+
+    # new method will fetch height based on new option, or default to 450px
+    new_method <- function(x, ...) {
+      x$height <- getOption("db_htmlwidget_height", 450)
+      file <- tempfile(fileext = ".html")
+      htmlwidgets::saveWidget(x, file = file)
+      contents <- as.character(rvest::read_html(file))
+      displayHTML(contents)
+    }
+
+    utils::assignInNamespace("print.htmlwidget", new_method, ns = "htmlwidgets")
+    invisible(list(default_height = height, print = new_method))
+  }
+}

_pkgdown.yml

@@ -49,6 +49,11 @@ reference:
   contents:
   - starts_with("db_libs", internal = TRUE)
   - wait_for_lib_installs
+- title: Databricks Notebook Helpers
+  contents:
+   - in_databricks_nb
+   - notebook_use_posit_repo
+   - notebook_enable_htmlwidgets
 - title: DBFS
   contents: starts_with("db_dbfs", internal = TRUE)
 - title: Volume FileSystem

tests/testthat/test-connection-pane.R

@@ -113,12 +113,15 @@ test_that("Connection Pane Helpers", {
       host = db_host(),
       token = db_token()
     )
+    # remove serverless clusters from test as they cause an issue
+    clusters <- clusters[!grepl("v2n", clusters$name), ]
     cluster_id <- get_id_from_panel_name(clusters$name[[1]])
     cluster_data <- get_cluster(
       id = cluster_id,
       host = db_host(),
       token = db_token()
     )
+
   })
   expect_type(clusters, "list")
   expect_type(cluster_data, "list")

tests/testthat/test-notebook-helpers.R

@@ -0,0 +1,8 @@
+test_that("Databricks Notebook Helpers", {
+
+  # currently running tests outside of a databricks notebook
+  expect_false(in_databricks_nb())
+  expect_no_error(notebook_use_posit_repo())
+  expect_no_error(notebook_enable_htmlwidgets())
+
+})