{databricks} but it's an R6 object

databricks-env.R

databricks <- local(envir = new.env(), {
  .self <- environment()
  .client <- NULL
  
  .call <- function(method, args) {
    if (is.null(.client)) {
      stop(
        "No client conigured",
        "\nplease use $configure() function to set client",
        call. = FALSE
      )
    }
    args$client <- .client
    fun <- get(method, envir = asNamespace("databricks"))
    res <- do.call(fun, args)
    if (inherits(res, "data.frame") && requireNamespace("tibble", quietly = TRUE)) {
      res <- tibble::as_tibble(res)
    }
    class(res) <- c("databricks", class(res))
    res
  }
  
  configure <- function() {}
  formals(configure) <- formals(databricks::DatabricksClient)
  body(configure) <- substitute({
    args <- as.list(match.call())[-1L]
    assign(".client", do.call(databricks::DatabricksClient, args), .self)
    invisible(.self)
  })
  
  local({
    databricks_exports <- getNamespaceExports("databricks")
    if (utils::packageVersion("databricks") <= "0.4.0") {
      # All functions are 
      databricks_exports <- grep("^[a-z]+[A-Z][a-z]+$", databricks_exports, value = TRUE)
    } else {
      # But were changes to snake_case
      databricks_exports <- grep("^[a-z_]+$", databricks_exports, value = TRUE)
    }
    
    for (i in databricks_exports) {
      fun <- get0(i, envir = asNamespace("databricks"), mode = "function")
      
      if (is.null(fun)) {
        next
      }
      
      args <- formals(fun)
      
      if (!isTRUE(names(args)[1L] == "client")) {
        next
      }
      
      method <- function() {} 
      formals(method) <- args[-1L]
      body(method) <- substitute({
        .call(i, as.list(match.call())[-1L])
      })
      
      assign(i, method, envir = .self)
    }
  })
  
  .self
})

try(databricks$clustersList())
databricks$configure()

if (packageVersion("databricks") <= "0.4.0") {
  databricks$clustersList()
} else {
  databricks$list_clusters()
}

databricks-r6.R

databricks_client <- R6::R6Class(
  "dbClient",
  public = local({
    databricks_exports <- getNamespaceExports("databricks")
    if (utils::packageVersion("databricks") <= "0.4.0") {
      # All functions are 
      databricks_exports <- grep("^[a-z]+[A-Z][a-z]+$", databricks_exports, value = TRUE)
    } else {
      # But were changes to snake_case
      databricks_exports <- grep("^[a-z_]+$", databricks_exports, value = TRUE)
    }
    
    res <- list()
    res$initialize <- function() {} 
    formals(res$initialize) <- formals(databricks::DatabricksClient)
    body(res$initialize) <- substitute({
      args <- as.list(match.call())[-1L]
      private$client <- do.call(databricks::DatabricksClient, args)
      self
    })
    
    for (i in databricks_exports) {
      fun <- get0(i, envir = asNamespace("databricks"), mode = "function")
      
      if (is.null(fun)) {
        next
      }
      
      args <- formals(fun)
      
      if (!isTRUE(names(args)[1L] == "client")) {
        next
      }
      
      method <- function() {} 
      formals(method) <- args[-1L]
      body(method) <- substitute({
        private$call(i, as.list(match.call())[-1L])
      })
      
      res[[i]] <- method
    }
    
    res
  }),
  private = list(
    client = NULL,
    call = function(method, args) {
      args$client <- private$client
      fun <- get(method, envir = asNamespace("databricks"))
      res <- do.call(fun, args)
      if (inherits(res, "data.frame") && requireNamespace("tibble", quietly = TRUE)) {
        res <- tibble::as_tibble(res)
      }
      class(res) <- c("databricks", class(res))
      res
    }
  )
)

print.databricks <- function(x, ...) {
  if (inherits(x, "data.frame")) {
    NextMethod()
  }
  
  if (inherits(x, "list")) {
    if (requireNamespace("yaml", quietly = TRUE)) {
      yaml::write_yaml(x, file = stdout())
    } else {
      utils::str(x)
    }
    return(invisible(x))
  }
  
  NextMethod()
}

client <- databricks_client$new()
if (packageVersion("databricks") <= "0.4.0") {
  client$clustersList()
} else {
  client$list_clusters()
}