R/ee_grab_install.R

In johnwasige/earthEngineGrabR: Simplify the acquisition of remote sensing data

#' Install dependencies and run authentications
#' 
#' @param clean_credentials \code{logical}, if \code{True} already present credential are deleted recreated by a reauthenticate. Default is set to \code{True}.
#' @param clean_environment \code{logical}, if \code{True} already installed environments are deleted to be reinstalled again. Default is set to \code{False}.
#' @description \code{ee_grab_install()} installs the required dependencies and guides the user through the authentication processes to activate the different API's.
#' @export
#' 
#' 
#' @section Installation of Dependencies:
#' 
#' To encapsulate the dependencies from the user's system and simplify the installation,  the \code{earthEngineGrabR} uses a conda environment.
#' By running \code{ee_grab_install()} first a conda environemt "earthEngineGrabR" is created. 
#' All Further all dependencies are installed inside the "earthEngineGrabR" environment.
#' 

#' @section Authentication of API's:
#' 
#' The earthEngineGrabR connects to 3 Google API's: 
#' 
#'   \href{https://www.gdal.org/drv_gft.html}{Google Fusion Table} API for uploading data. 
#'   
#'   \href{https://developers.google.com/earth-engine/}{Google Earth Engine} API for data aquisition and processing.  
#'   
#'   \href{https://github.com/tidyverse/googledrive}{Google Drive} API for data download. 
#'
#' To authenticate to the API's the user has to log in with his google account and allow the API to access data on googles servers on the user's behalf. 
#' To simplify this procedure the ee_grab_install function successively opens a browser window to log into the Google account.
#' If the Google account is verified and the permission is granted, the user is directed to an authentification token. This token is manually copied and pasted into the R console, which creates persistent credentials. 
#' This process is repeated for each API. If the function runs successfully, all needed credentials are stored for further sessions and there should be no need for further authentification.
#' 
#' 
ee_grab_install <- function(clean_credentials = T, clean_environment = F) {
  
  # test installation of sf
  sf_test <- require(sf, quietly = T)
  if (!sf_test) stop("Library sf could not be loaded \nPlease install sf to use earthEngineGrabR", call. = F)

  library(reticulate)
  # install dependencies -----------------------------------------------------------------------------------------
  
  # initialize environments 
  conda_env_name <- "earthEngineGrabR"
  
  # if clean_environment is set to true already an existing environment is deleted
  if (clean_environment) clean_environments(conda_env_name)
  
  # test if environment for dependeicies already exists
  env_test <- grepl(conda_env_name, conda_list()$name)
  
  # install dependencies via an anaconda environment if test is not treu
  if (!sum(env_test) > 0) {
    tryCatch({
      if (Sys.info()[["sysname"]] != "Linux") {
        conda_create(conda_env_name, packages = c("Python = 2.7", "gdal"))
        
        conda_install(conda_env_name, packages = c("earthengine-api", "shapely"))
        
      } else {
        
        conda_create(conda_env_name,
                     packages = c("Python = 2.7", "gdal=2.1.0", "geos=3.5.0"))
        conda_install(conda_env_name,
                      packages = c("earthengine-api", "shapely", 'oauth2client'))
      }},
      error = function(err)
        stop(paste("Installation problem\n", err), call. = F)
      
    )
  }
  use_condaenv(conda_env_name)

  # test import of all modules.
  tryCatch({
  test_ee <- py_module_available("ee")
  test_gdal <- py_module_available("gdal")

  if (!test_ee) stop("Module ee could not be imported", call. = F)
  if (!test_gdal) stop("Module gdal could not be imported", call. = F)
  
  }, error = function(err) {
    test_python()
    test_anaconda()
    stop(paste("Installation problem\n", err), call. = F)
  },
  warning = function(w) {
    warning(w)
  })
  
  # run authentication ---------------------------------------------------------------
  
  # if no credential are found run authentication
  if (!test_credentials(with_error = F)) {
    run_oauth_all()
  } else {
    # if credential are found but clean_credentials is set to  true, credentials are deleted and recreated during a new authentication
    if (clean_credentials) {
      delete_credentials()
      run_oauth_all()
      }
  }
cat("\n \nThe required dependencies are installed and all API's are authenticated for further sessions.\nThere should be no need to run ee_grab_install() again.")
  }