[draft] tar_terra_rast: implement {gdalraster} SOZip preserve_metadata method

DESCRIPTION

@@ -47,7 +47,8 @@ Suggests:
     sf,
     stars,
     testthat (>= 3.0.0),
-    fs
+    fs,
+    gdalraster
 Config/testthat/edition: 3
 URL: https://github.com/njtierney/geotargets, http://geotargets.njtierney.com
 BugReports: https://github.com/njtierney/geotargets/issues

R/tar-terra-rast.R

@@ -83,12 +83,21 @@ tar_terra_rast <- function(name,
   drv <- get_gdal_available_driver_list("raster")
   filetype <- rlang::arg_match0(filetype, drv$name)
 
-  # currently only "drop" and "zip" are valid options
+  # various methods for packaging geospatial data and auxiliary files
   preserve_metadata <- preserve_metadata %||% "drop"
-  preserve_metadata <- rlang::arg_match0(preserve_metadata, c("drop", "zip"))
+  preserve_metadata <- rlang::arg_match0(preserve_metadata, c("drop", "zip", "gdalraster_sozip"))
 
   # ensure that user-passed `resources` doesn't include `custom_format`
   check_user_resources(resources)
+
+  if (preserve_metadata == "gdalraster_sozip") {
+      check_pkg_installed("gdalraster")
+  }
+
+  # ensure that user-passed `resources` doesn't include `custom_format`
+  if ("custom_format" %in% names(resources)) {
+      cli::cli_abort("{.val custom_format} cannot be supplied to targets created with {.fn tar_terra_rast}")
+  }
 
   name <- targets::tar_deparse_language(substitute(name))
 
@@ -135,50 +144,88 @@ tar_terra_rast <- function(name,
 }
 
 tar_rast_read <- function(preserve_metadata) {
-  switch(preserve_metadata,
-    zip = function(path) {
-      tmp <- withr::local_tempdir()
-      zip::unzip(zipfile = path, exdir = tmp)
-      terra::rast(file.path(tmp, basename(path)))
-    },
-    drop = function(path) terra::rast(path)
-  )
+    switch(
+        preserve_metadata,
+        zip = function(path) {
+            tmp <- withr::local_tempdir()
+            zip::unzip(zipfile = path, exdir = tmp)
+            terra::rast(file.path(tmp, basename(path)))
+        },
+        gdalraster_sozip = function(path) {
+          terra::rast(paste0("/vsizip/{", path, "}/"), basename(path))
+        },
+        drop = function(path) terra::rast(path)
+    )
 }
 
 tar_rast_write <- function(filetype, gdal, preserve_metadata) {
-  switch(preserve_metadata,
-    zip = function(object, path) {
-      # write the raster in a fresh local tempdir() that disappears when function is done
-      tmp <- withr::local_tempdir()
-      dir.create(file.path(tmp, dirname(path)), recursive = TRUE)
-      terra::writeRaster(
-        object,
-        file.path(tmp, path),
-        filetype = filetype,
-        overwrite = TRUE,
-        gdal = gdal
-      )
-      # package files into a zip file using `zip::zip()`
-      raster_files <- list.files(file.path(tmp, dirname(path)), full.names = TRUE)
-      zip::zip(
-        file.path(tmp, basename(path)),
-        files = raster_files,
-        compression_level = 1,
-        mode = "cherry-pick",
-        root = dirname(raster_files)[1]
-      )
-      # move the zip file to the expected place
-      file.copy(file.path(tmp, basename(path)), path)
-      unlink(file.path(tmp, basename(path)))
-    },
-    drop = function(object, path) {
-      terra::writeRaster(
-        object,
-        path,
-        filetype = filetype,
-        overwrite = TRUE,
-        gdal = gdal
-      )
-    }
-  )
+    switch(
+        preserve_metadata,
+        zip = function(object, path) {
+            #write the raster in a fresh local tempdir() that disappears when function is done
+            tmp <- withr::local_tempdir()
+            dir.create(file.path(tmp, dirname(path)), recursive = TRUE)
+            terra::writeRaster(
+                object,
+                file.path(tmp, path),
+                filetype = filetype,
+                overwrite = TRUE,
+                gdal = gdal
+            )
+            #package files into a zip file using `zip::zip()`
+            raster_files <- list.files(file.path(tmp, dirname(path)), full.names = TRUE)
+            zip::zip(
+                file.path(tmp, basename(path)),
+                files = raster_files,
+                compression_level = 1,
+                mode = "cherry-pick",
+                root = dirname(raster_files)[1]
+            )
+
+          # move the zip file to the expected place
+          file.copy(file.path(tmp, basename(path)), path)
+          unlink(file.path(tmp, basename(path)))
+        },
+        gdalraster_sozip = function(object, path) {
+
+            tmp <- withr::local_tempdir()
+
+            dir.create(file.path(tmp, dirname(path)), recursive = TRUE)
+
+            terra::writeRaster(
+                object,
+                file.path(tmp, path),
+                filetype = filetype,
+                overwrite = TRUE,
+                gdal = gdal
+            )
+
+            raster_files <- list.files(file.path(tmp, dirname(path)), full.names = TRUE)
+
+            # create seek-optimized zip file using gdalraster
+            gdalraster::addFilesInZip(
+                path,
+                raster_files,
+                full_paths = FALSE,
+                overwrite = TRUE,
+                sozip_enabled = "YES",
+                num_threads = 1,
+                quiet = TRUE
+            )
+            # always create sozip regardless of file size (sozip_enabled = "YES")
+            # TODO: allow user control of number of threads?
+            #       how does num_threads interact multiple workers etc.?
+
+            unlink(file.path(tmp, path))
+        },
+        drop = function(object, path) {
+            terra::writeRaster(
+                object,
+                path,
+                filetype = filetype,
+                overwrite = TRUE,
+                gdal = gdal
+            )
+        }
+    )
 }