layout_gha for native GitHub Action logging

NAMESPACE

@@ -43,6 +43,7 @@ export(formatter_sprintf)
 export(get_logger_meta_variables)
 export(grayscale_by_log_level)
 export(layout_blank)
+export(layout_gha)
 export(layout_glue)
 export(layout_glue_colors)
 export(layout_glue_generator)

NEWS.md

@@ -7,6 +7,7 @@
 * `log_appender()`, `log_layout()` and `log_formatter()` now check that you are calling them with a function, and return the previously set value (#170, @hadley)
 * new function to return number of log indices (#194, @WurmPeter)
 * `appender_async` is now using `mirai` instead of a custom background process and queue system (#214, @hadley @shikokuchuo)
+* `layout_gha()` for providing native GitHub Action logging. This automatically gets used when running code in github actions (@thomasp85)
 
 ## Fixes
 

R/layouts.R

@@ -330,6 +330,47 @@ default_fields <- function() {
   )
 }
 
+#' Format a log record for github actions
+#'
+#' GitHub Actions can recognise specially formatted output and make these
+#' prominent in the output. The `layout_gha()` layout will ensure the correct
+#' formatting when running in GitHub Actions.
+#'
+#' @note
+#' GitHub Actions only recognise the log levels `error`, `warning`, `notice`,
+#' and `debug`. Because of this, `FATAL` and `ERROR` are coerced to `error`,
+#' `SUCCESS` and `INFO` are coerced to `notice`, and `DEBUG` and `TRACE` are
+#' coerced to `debug` (`WARN` maps directly to `warning`).
+#'
+#' @inheritParams layout_simple
+#' @return character vector
+#' @export
+#' @family log_layouts
+#'
+layout_gha <- structure(
+  function(level,
+           msg,
+           namespace = NA_character_,
+           .logcall = sys.call(),
+           .topcall = sys.call(-1),
+           .topenv = parent.frame()) {
+    level <- attr(level, "level")
+    gha_level <- switch(level,
+      FATAL = ,
+      ERROR = "error",
+      WARN = "warning",
+      SUCCESS = ,
+      INFO = "notice",
+      DEBUG = ,
+      TRACE = "debug",
+      "notice" # Defaults to notice if for some reason another level gets used
+    )
+    title <- if (gha_level == "debug") "" else paste0(" title=", level)
+    paste0("::", gha_level, title, "::", msg)
+  },
+  generator = quote(layout_gha())
+)
+
 # nocov start
 #' Format a log record for syslognet
 #'

R/zzz.R

@@ -12,22 +12,23 @@ namespaces_reset <- function() {
 
 namespaces_default <- function() {
   has_glue <- requireNamespace("glue", quietly = TRUE)
+  is_running_gha <- isTRUE(Sys.getenv("GITHUB_ACTIONS") == "true") && !needs_stdout()
 
   list(
     global = list(
       default = list(
         threshold = as.loglevel(Sys.getenv("LOGGER_LOG_LEVEL", unset = "INFO")),
-        layout    = layout_simple,
+        layout    = if (is_running_gha) layout_gha else layout_simple,
         formatter = if (has_glue) formatter_glue else formatter_sprintf,
-        appender  = if (needs_stdout()) appender_stdout else appender_console
+        appender  = if (is_running_gha) appender_stderr else if (needs_stdout()) appender_stdout else appender_console
       )
     ),
     .logger = list(
       default = list(
         threshold = ERROR,
-        layout    = layout_simple,
+        layout    = if (is_running_gha) layout_gha else layout_simple,
         formatter = formatter_sprintf,
-        appender  = if (needs_stdout()) appender_stdout else appender_console
+        appender  = if (is_running_gha) appender_stderr else if (needs_stdout()) appender_stdout else appender_console
       )
     )
   )