Sample scripts that demonstrate how to submit logging data to the Azure Monitor HTTP Data Collector API from R.

logger_utils.R

require(caTools)
require(digest)
require(httr)
require(jsonlite)

#' Build API signature for logging to Azure log analytics
#'
#' Azure log analytics HTTP REST API documentation for Python is followed to
#' create the R version of it. Python version of this function is described
#' at \url{https://docs.microsoft.com/en-us/azure/azure-monitor/logs/data-collector-api#python-3-sample}
#'
#' @param customer_id \code{customer_id} of the Azure log analytics workspace
#' @param shared_key \code{shared_key} of the Azure log analytics workspace
#' @param date datetime of logging event
#' @param content_length Content length of the body
#' @param method Only one value is expected - \code{POST}
#' @param content_type Only one value is expected - \code{application/json}
#' @param resource Only one value is expected - \code{/api/logs}
#' @return Returns part of the header of HTTP POST request to be sent to Azure
#'     log analytics workspace
.build_signature <- function(customer_id, shared_key, date, content_length,
                             method, content_type, resource) {
  x_headers <- paste0("x-ms-date:", date)
  string_to_hash <- paste0(method, "\n", content_length, "\n",
                           content_type, "\n", x_headers, "\n", resource)
  bytes_to_hash <- charToRaw(enc2utf8(string_to_hash))
  decoded_key <- caTools::base64decode(shared_key, "raw")
  encoded_hash <- caTools::base64encode(digest::hmac(decoded_key, bytes_to_hash,
                                                     algo = "sha256",
                                                     serialize = FALSE,
                                                     raw = TRUE))
  authorization <- paste0("SharedKey ", customer_id, ":", encoded_hash)
  return(authorization)
}


#' Build and send a request to the POST API of Azure log analytics
#'
#' @inherit .build_signature details
#'
#' @param customer_id \code{customer_id} of the Azure log analytics workspace
#' @param shared_key \code{shared_key} of the Azure log analytics workspace
#' @param body Content or message to be logged in json format
#' @param log_type Log-Type as defined in Azure document, for custom logging
#' @return Returns the HTTP response object
#' @examples \dontrun{
#'   .post_data(
#'     "xxxx", "yyyy", 
#'     as.character(jsonlite::toJSON(list(level="info", message="test"), 
#'                  auto_unbox = TRUE)), 
#'     "test"
#'   )
.post_data <- function(customer_id, shared_key, body, log_type) {
  method <- "POST"
  content_type <- "application/json"
  resource <- "/api/logs"
  rfc1123date <- as.character(strftime(as.POSIXlt(Sys.time(), tz = "UTC"),
                                       "%a, %d %b %Y %H:%M:%S GMT"))
  content_length <- nchar(body)
  signature <- .build_signature(customer_id, shared_key, rfc1123date,
                                content_length, method, content_type, resource)
  uri <- paste0("https://", customer_id, ".ods.opinsights.azure.com",
                resource, "?api-version=2016-04-01")
  headers <- httr::add_headers(.headers = c("Content-Type" = content_type,
                                            "Authorization" = signature,
                                            "Log-Type" = log_type,
                                            "x-ms-date" = rfc1123date))
  response <- httr::POST(uri, config = headers, body = body)
  return(response)
}