Merge pull request #3 from TileDB-Inc/aw/callr-backend

Migrate backend to callr

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: tiledbJupyterShiny
 Type: Package
 Title: Render Shiny apps inside a Jupyter notebook
-Version: 0.1.1.9001
+Version: 0.1.2
 Author: TileDB
 Maintainer: TileDB <[email protected]>
 Description: Render Shiny apps inside a Jupyter notebook.
@@ -11,6 +11,7 @@ LazyData: true
 Imports:
     IRdisplay,
     shiny,
-    future
+    callr,
+    pingr
 Roxygen: list(markdown = TRUE)
 RoxygenNote: 7.1.1

Dockerfile

@@ -13,7 +13,7 @@ RUN mamba install -c conda-forge --quiet --yes \
   'bash_kernel' \
   'r-shiny' \
   'r-irkernel' \
-  'r-future' \
+  'r-pingr' \
   && mamba clean --all -f -y
 
 # install the tiledbJupyterShiny package

NAMESPACE

@@ -1,6 +1,7 @@
 # Generated by roxygen2: do not edit by hand
 
 export(renderShinyApp)
-import(future)
 import(shiny)
 importFrom(IRdisplay,display_html)
+importFrom(callr,r_bg)
+importFrom(pingr,is_up)

NEWS.md

@@ -0,0 +1,5 @@
+# tiledbJupyterShiny 0.1.2
+
+* Added a `NEWS.md` file to track changes to the package.
+* Apps are now launched as background tasks using the *callr* package.
+* We now verify an app is up and running before rendering the IFrame

R/renderShinyApp.R

@@ -1,20 +1,21 @@
 #' Render Shiny Application in a Jupyter Notebook
 #' 
 #' @param ui The UI definition of the app.
+#' @param port The TCP port that the application should listen on (defaults to 3000).  
 #' @inheritParams shiny::shinyApp
 #' @importFrom IRdisplay display_html
 #' @import shiny
-#' @import future
+#' @importFrom callr r_bg
+#' @importFrom pingr is_up
 #' @export
 
 renderShinyApp <- function(
   ui = NULL, 
   server = NULL, 
   appFile = NULL,
-  appDir = NULL
+  appDir = NULL,
+  port = 3000
 ) {
-  port <- 3000
-
   if (!is.null(ui) || !is.null(server)) {
     app <- shiny::shinyApp(ui, server)
   } else if (!is.null(appFile)) {
@@ -28,11 +29,22 @@ renderShinyApp <- function(
     )
   }
 
-  plan(multisession)
-  future::future(runApp(app, host = "0.0.0.0", port = port))
+  run_app <- function(appDir, host, port) {
+    shiny::runApp(appDir, host = host, port = port)
+  }
+  args <- list(appDir = app, host = "0.0.0.0", port = port)
+
+  rproc <- callr::r_bg(
+    func = run_app,
+    args = args,
+    supervise = TRUE
+  )
 
-  Sys.sleep(1)
-  displayIframe(port)
+  while(!pingr::is_up(destination = args$host, port = args$port)) {
+    if (!rproc$is_alive()) stop(rproc$read_all_error())
+    Sys.sleep(0.05)
+  }
+  displayIframe(port = args$port)
 }