Monaλog

Monalog is terminal logs observer.

Installation

1. Clone the repo
2. run cabal install exe:monalog
3. Enjoy

Running

monalog --help
Usage: monalog [COMMAND | [FILE] [-f|--format FORMAT] [-d|--default-field FIELD]
                 [-c|--config CONFIG] [-i|--ignore-config ARG]]

Available options:
  FILE                     The format can be derived from the file format. If
                           the file format is .csv, the output will be csv,
                           otherwise it will be json.
  -f,--format FORMAT       Supported formats: json, csv. In the case of csv, the
                           first line is considered the header.
  -i,--ignore-config ARG   Expected values: global, local, all
  -h,--help                Show this help text

Available commands:
  config                   Work with config

monalog my_logs.json
# or 
monalog my_logs.csv
# or
run_logging_server | monalog --format=csv 
# or
run_logging_server | monalog --format=json 

Usage

Hot key	Action
Ctrl + q	Cleanup logs
Ctrl + d	Exit
t	Go to top
b	Go to bottom
g	Go to
h, left	Shift left
H, Shift + left	Long shift left
l, right	Shift right
L, Shift + right	Log shift right
j, up	Shift up
J, Shift + up	Long shift up
k, down	Shift down
K, Shift + down	Long shift down
s	Select top line log
scroll	Shift up/down
Ctrl + scroll	Shift left/right

NOTE: some combinations with Ctrl and Shift can be handled by your terminal

Mouse is fully supported. You can

• click buttons (all text within [..])
• move fields and log entry view bounds.
• move columns with < > buttons around header
• activate query / jsonpath / editors
• move horizontal view ports

Query language

Operators	Details
= , !=
>, <	Compares number with number, string with string, bool with bool. Otherwise returns false
>=, <=	Exactly >/< or =
&&, ||	Works with bool. For operands of other types returns false
not	Negates argument
like	Fuzzy text comparison
in	Checks if left operand is element of list in right operand`

Literal	Example
number	5, 34.2, -42
string	"foo", "foo \"hello\""
bool	true, false
array	[1, true, "bar"]
key	_42foo, fOooBar, $"any \"string\" 1"

Copying

Monalog supports two way to copy data:

• Native. Monalog calls platform specific commands (which can be overwritten with config). Default commands:

  OS	Command
  Macos	pbcopy
  Windows	clip
  Linux	xclip -sel clip

• Osc52. Check out if your terminal supports OSC52

Copying is available in log entry view using [Copy] button

Log view

Log view supports jsonpath queries. Jsonpath filter can be disabled/enabled with checkbox

Fields view

Monalog automatically detects fields appear in your logs. Fields view supports 2 display mods

• Flatten
• Nested

which can be toggled with button [Nested]/[Flatten]

Input formats

Format	Details
json	Means jsonlines. If line is not valid JSON then line is put to default field of JSON ( { "message": "some invalid json" } ). Default field is message but can it be overwritten via cli or config
csv	The first line is supposed to be header

Config

By default monalog tries load config monalog.yaml from $PWD. You can disable it with -i or --ignore-config You can also specify path to config with -c or --config Here is example of monalog config:

fields:
  - "@timestamp" # builtin field. Indicates the time when monalog get log line
  - "@raw" # builtin field. Indicates whole log json
  - foo.bar 
format: csv # csv / json
defaultField: data.msg # useful for json only 
copyMethod: native # native / osc52
copyCommand: "xclip -sel clip"

Monalog can create config automatically

monalog config create --global # creates global config
monalog config create # creates local config

To find out where is config located use the following command

monalog config path global

To get more info use --help

---

Thanks to @ShrykeWindgrace for help with Windows support implementation