pino-logfmt v0.0.4

pino-logfmt

This package provides a transport that transforms standard pino logs to logfmt.

A standard Pino log line like:

{"level":30,"time":1522431328992,"msg":"hello world","pid":42,"hostname":"foo","v":1}

Will format to:

level=30 time=1522431328992 msg="hello world" pid=42 hostname=foo v=1

Install

npm install pino-logfmt

Example

Using the example script from the Pino module, we can see what the prettified logs will look like:

node examples/basic.js | pino-logfmt --flatten-nested --snake-case
level=30 time=1710427304769 pid=78824 hostname=MacBook-Pro-de-Victor-2.local msg="hello world"
level=50 time=1710427304769 pid=78824 hostname=MacBook-Pro-de-Victor-2.local msg="this is at error level"
level=30 time=1710427304769 pid=78824 hostname=MacBook-Pro-de-Victor-2.local msg="the answer is 42"
level=30 time=1710427304769 pid=78824 hostname=MacBook-Pro-de-Victor-2.local obj=42 msg="hello world"
level=30 time=1710427304769 pid=78824 hostname=MacBook-Pro-de-Victor-2.local obj=42 b=2 msg="hello world"
level=30 time=1710427304769 pid=78824 hostname=MacBook-Pro-de-Victor-2.local nested_obj=42 msg=nested
level=50 time=1710427304770 pid=78824 hostname=MacBook-Pro-de-Victor-2.local err_type=Error err_message="an error" err_stack="Error: an error
    at Object.<anonymous> (/Users/victor/Documents/projects/pino-logfmt/node_modules/pino/examples/basic.js:21:12)
    at Module._compile (node:internal/modules/cjs/loader:1256:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1310:10)
    at Module.load (node:internal/modules/cjs/loader:1119:32)
    at Module._load (node:internal/modules/cjs/loader:960:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
    at node:internal/main/run_main_module:23:47" msg="an error"
level=30 time=1710427304770 pid=78824 hostname=MacBook-Pro-de-Victor-2.local a=property msg="hello child!"
level=30 time=1710427304770 pid=78824 hostname=MacBook-Pro-de-Victor-2.local a=property another=property msg="hello baby.."
level=20 time=1710427304770 pid=78824 hostname=MacBook-Pro-de-Victor-2.local msg="this is a debug statement"
level=20 time=1710427304770 pid=78824 hostname=MacBook-Pro-de-Victor-2.local another=property msg="this is a debug statement via child"
level=10 time=1710427304770 pid=78824 hostname=MacBook-Pro-de-Victor-2.local msg="this is a trace statement"
level=20 time=1710427304770 pid=78824 hostname=MacBook-Pro-de-Victor-2.local msg="this is a \"debug\" statement with \""
level=30 time=1710427304770 pid=78824 hostname=MacBook-Pro-de-Victor-2.local err_type=Error err_message=kaboom err_stack="Error: kaboom
    at Object.<anonymous> (/Users/victor/Documents/projects/pino-logfmt/node_modules/pino/examples/basic.js:40:11)
    at Module._compile (node:internal/modules/cjs/loader:1256:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1310:10)
    at Module.load (node:internal/modules/cjs/loader:1119:32)
    at Module._load (node:internal/modules/cjs/loader:960:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
    at node:internal/main/run_main_module:23:47" msg=kaboom
level=30 time=1710427304770 pid=78824 hostname=MacBook-Pro-de-Victor-2.local
level=30 time=1710427304770 pid=78824 hostname=MacBook-Pro-de-Victor-2.local err_type=Error err_message=kaboom err_stack="Error: kaboom
    at Object.<anonymous> (/Users/victor/Documents/projects/pino-logfmt/node_modules/pino/examples/basic.js:43:11)
    at Module._compile (node:internal/modules/cjs/loader:1256:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1310:10)
    at Module.load (node:internal/modules/cjs/loader:1119:32)
    at Module._load (node:internal/modules/cjs/loader:960:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
    at node:internal/main/run_main_module:23:47" msg=with
level=30 time=1710427304771 pid=78824 hostname=MacBook-Pro-de-Victor-2.local msg="after setImmediate"

Programmatic usage

const pino = require("pino")

const logger = pino({
    transport: {
        target: "pino-logfmt",
        options: {
            flattenNestedObjects: true,
            convertToSnakeCase: true,
        }
    }
})

logger.info("Hello world")

Options

CLI usage

The transport is also available using a CLI through. Almost all the options are available as CLI arguments. Like other CLIs, you can print the help message using --help as followed:

npx pino-logfmt --help

Usage: pino-logfmt [options]

Logfmt transport for pino

Options:
  -V, --version                 output the version number
  --include-level-label         add the level as a label (default: false)
  --level-label-key <string>    the key of the level label (default: "level_label")
  --format-time                 format the timestamp into an ISO date (default: false)
  --time-key <string>           the key that holds the timestamp (default: "time")
  --snake-case                  convert the keys to snake case (default: false)
  --flatten-nested              flatten nested metadata (default: false)
  --flatten-separator <string>  the separator used when flattening nested metadata (default: ".")
  --custom-levels, -x <string>  the levels associated to their labels in the format "10:trace,20:debug" (default: "10:trace,20:debug,30:info,40:warn,50:error,60:fatal")
  --time-format <string>        the time format to use if time formatting is enabled (default: "isoDateTime")
  --escape-multiline-strings    escape multi-line strings in the log output, including deeply nested values (default: false)
  -h, --help                    display help for command

node process-that-emits-logs.js | pino-logfmt

Flags

Contributing

To get started, you must clone the project and install dependencies. This project also include a .devcontainer configuration so everyone can run the same environment.

git clone git@github.com:botflux/pino-logfmt.git
npm ci

Code is linted in commit using lint-staged. The linter is standard. You can run the linter before commiting using npm run lint.

The project is tested using mocha and chai. Run npm run test to run the tests.