[scuba] support string payloads

Summary: Add a string-valued log message.

Reviewed By: jvillard

Differential Revision: D20895742

fbshipit-source-id: 0eab54c6d

infer/src/scuba/LogEntry.ml

@@ -11,7 +11,9 @@ type count_entry_data = {value: int}
 
 type time_entry_data = {duration_ms: int}
 
-type entry_data = Count of count_entry_data | Time of time_entry_data
+type string_data = {message: string}
+
+type entry_data = Count of count_entry_data | Time of time_entry_data | String of string_data
 
 type t = {label: string; created_at_ts: int; data: entry_data}
 
@@ -27,6 +29,12 @@ let mk_time ~label ~duration_ms =
   {label; created_at_ts; data}
 
 
+let mk_string ~label ~message =
+  let created_at_ts = Unix.time () |> int_of_float in
+  let data = String {message} in
+  {label; created_at_ts; data}
+
+
 (** What _global_ mean at this point is subject to discussion. Right now there is only one use-case
     which is Scuba+Scribe logging at the end of execution. But there might be more. Let's change the
     naming accordingly when the purpose gets clearer. *)

infer/src/scuba/LogEntry.mli

@@ -14,7 +14,9 @@ type count_entry_data = {value: int}
 
 type time_entry_data = {duration_ms: int}
 
-type entry_data = Count of count_entry_data | Time of time_entry_data
+type string_data = {message: string}
+
+type entry_data = Count of count_entry_data | Time of time_entry_data | String of string_data
 
 (** created_at_ts is a unix timestamp (in seconds) *)
 type t = {label: string; created_at_ts: int; data: entry_data}
@@ -23,6 +25,8 @@ val mk_count : label:string -> value:int -> t
 
 val mk_time : label:string -> duration_ms:int -> t
 
+val mk_string : label:string -> message:string -> t
+
 val global_log_get : unit -> t list
 
 val global_log_erase : unit -> unit

infer/src/scuba/ScubaLogging.ml

@@ -39,17 +39,21 @@ let set_common_fields sample =
 
 
 let sample_from_event ({label; created_at_ts; data} : LogEntry.t) =
-  let event_name, value =
-    match data with
-    | LogEntry.Count {value} ->
-        (Printf.sprintf "count.%s" label, value)
-    | LogEntry.Time {duration_ms} ->
-        (Printf.sprintf "time.%s" label, duration_ms)
+  let create_sample_with_label label =
+    Scuba.new_sample ~time:(Some created_at_ts)
+    |> set_common_fields |> set_command_line_normales |> set_command_line_tagsets
+    |> Scuba.add_normal ~name:"event" ~value:label
   in
-  Scuba.new_sample ~time:(Some created_at_ts)
-  |> set_common_fields |> set_command_line_normales |> set_command_line_tagsets
-  |> Scuba.add_normal ~name:"event" ~value:event_name
-  |> Scuba.add_int ~name:"value" ~value
+  match data with
+  | Count {value} ->
+      create_sample_with_label (Printf.sprintf "count.%s" label)
+      |> Scuba.add_int ~name:"value" ~value
+  | Time {duration_ms} ->
+      create_sample_with_label (Printf.sprintf "time.%s" label)
+      |> Scuba.add_int ~name:"value" ~value:duration_ms
+  | String {message} ->
+      create_sample_with_label (Printf.sprintf "msg.%s" label)
+      |> Scuba.add_normal ~name:"message" ~value:message
 
 
 (** Consider buffering or batching if proves to be a problem *)
@@ -66,6 +70,8 @@ let log_one entry = log_many [entry]
 
 let log_count ~label ~value = log_one (LogEntry.mk_count ~label ~value)
 
+let log_message ~label ~message = log_one (LogEntry.mk_string ~label ~message)
+
 let execute_with_time_logging label f =
   let ret_val, duration_ms = Utils.timeit ~f in
   let entry = LogEntry.mk_time ~label ~duration_ms in

infer/src/scuba/ScubaLogging.mli

@@ -16,7 +16,11 @@ val log_many : LogEntry.t list -> unit
     aggregated results at once. *)
 
 val log_count : label:string -> value:int -> unit
-(** Log anything that can be counted. Events will be prefixed with "count." *)
+(** Log anything that can be counted. Events will be prefixed with ["count."] *)
+
+val log_message : label:string -> message:string -> unit
+  [@@warning "-32"]
+(** Log a [string]. Event is prefixed with ["msg."] *)
 
 val execute_with_time_logging : string -> (unit -> 'a) -> 'a
 (** A helper to log execution time of a particular function. Use this to measure a performance of a