---

summary: JSON Log Sink

---

Conifiguration

==============

Here we log to `/var/log/prosody/prosody.json`:

``` {.lua}

log = {

  -- your other log sinks

  info = "/var/log/prosody/prosody.log"

  -- add this:

  { to = "json", filename = "/var/log/prosody/prosody.json" };

}

```

## UDP

Alternatively, it can send logs via UDP:

```lua

log = {

  { to = "json", udp_host = "10.1.2.3", udp_port = "9999" };

}

```

Format

======

JSON log files consist of a series of `\n`-separated JSON objects,

suitable for mangling with tools like

[`jq`](https://stedolan.github.io/jq/).

Example (with whitespace and indentation for readability):

``` {.json}

{

   "args" : [],

   "datetime" : "2019-11-03T13:38:28Z",

   "level" : "info",

   "message" : "Client connected",

   "source" : "c2s55f267f5b9d0"

}

{

   "args" : [

      "user@example.net"

   ],

   "datetime" : "2019-11-03T13:38:28Z",

   "level" : "debug",

   "message" : "load_roster: asked for: %s",

   "source" : "rostermanager"

}

```

`datetime`

:   [XEP-0082]-formatted timestamp.

`source`

:   Log source, usually a module or a connected session.

`level`

:   `debug`, `info`, `warn` or `error`

`message`

:   The log message in `printf` format. Combine with `args` to get the

    final message.

`args`

:   Array of extra arguments, corresponding to `printf`-style `%s`

    formatting in the `message`.

Formatted message

-----------------

If desired, at the obvious expense of performance, the formatted version of

the string can be included in the JSON object by specifying the `formatted_as`

key in the logger config:

``` {.lua}

log = {

  -- ... other sinks ...

  { to = "json", formatted_as = "msg_formatted", filename = "/var/log/prosody/prosody.json" };

}

```

This will expose the formatted message in the JSON as separate `msg_formatted`

key. It is possible to override existing keys using this (for example, the

`message` key), but not advisible.