vlt 0.1 · OCaml Package

This module defines the concept of event and how to construct them.

type time

The type of event timestamps.

type t = private {

id : int;
(*
Event identifier.
*)
hostname : string;
(*
Host name of running program.
*)
process : int;
(*
Process identifier of running program.
*)
thread : int;
(*
Thread identifier of event source.
*)
timestamp : time;
(*
Event timestamp.
*)
relative : int;
(*
Time elapsed between application start and event construction.
*)
level : Level.t;
(*
Event level.
*)
logger : Name.t;
(*
Logger name.
*)
origin : Name.t;
(*
First logger that received the event.
*)
file : string;
(*
Location of event source.
*)
line : int;
(*
Location of event source.
*)
column : int;
(*
Location of event source.
*)
message : string;
(*
Event message.
*)
properties : (string * string) list;
(*
Event properties as an association list from keys to values.
*)
error : (exn * string) option;
(*
Event error (parameters being actual exception and exception backtrace).
*)

}

The type of log events.

val make : 
  Name.t ->
  Level.t ->
  ?origin:Name.t option ->
  ?file:string ->
  ?line:int ->
  ?column:int ->
  ?properties:(string * string) list ->
  ?error:exn option ->
  string ->
  t

make lg lv ~origin:o ~file:fn ~line:ln ~column:cl ~properties:p ~error:e m constructs a log event for logger lg with level lv, location being defined by fn (filename), ln (line) and cl (column). p is an association list providing user-defined properties, e is an optional exception to be recorded (with its backtrace), and o is the first logger receiving the event (when None, the origin is set to lg). Identifier, thread, timestamp, relative time, and backtrace are automatically generated.

val with_logger : Name.t -> t -> t

with_logger l e returns an event that is identical to e, except that its logger is equal to l.

val bindings : t -> (string * string) list

Returns the bindings for the passed event. The bindings are an association list to be used for event rendering. The following keys are defined:

"id" event identifier;
"hostname" host name of running program;
"process" process identifier of running program (a.k.a. pid);
"thread" thread identifier;
"sec" seconds of event timestamp;
"min" minutes of event timestamp;
"hour" hour of event timestamp;
"mday" day of month of event timestamp;
"month" month of year of event timestamp (as a number);
"monthname" month name of year of event timestamp (as a string);
"monthnm" abbreviated month name of year of event timestamp (as a string);
"year" year of event timestamp (on four digits);
"wday" day of week of event timestamp (as a string);
"time" event timestamp (epoch-based);
"relative" time elapsed between initilization and event creation;
"level" event level;
"logger" event logger;
"origin" first logger that received the event;
"file" event file (using "<nofile>" instead of the empty string);
"filebase" event file (without directory information);
"line" event line;
"column" event column;
"message" event message;
"properties" property list of event (format: "[k1: v1; ...; kn: vn]");
"exception" event exception;
"backtrace" event exception backtrace.

These keys have precedence over the one given at event creation.

val render_bindings : (string * string) list -> string -> string

render_bindings l fmt returns a string representing fmt where all bindings of the association list l have been expanded. Bindings, and their textual format are defined in render.

val render : string -> t -> string

render fmt e returns a string representing fmt where all bindings of e have been expanded. Bindings should appear in fmt is the $(id:pad) format where id is the binding key, and pad the optional padding. The padding consists of whitespace, on the right if pad is positive and on the left otherwise.

package vlt