# Structured Log Formatter
**Terminal utility to pretty-print JSON-strucutred log lines.**
# Usage
`slfmt` is intended to be used to filter logging output from a process. It
reads from `stdin` and writes to `stdout`. It expects to see a JSON object on
each line of input, and will pretty-print the object to `stdout`. Escape codes
in the log lines (`\n` for newlines, etc.) are supported and will be expanded
in the output.
Any lines that are not valid JSON objects will be printed as-is to `stdout`.
Example:
```bash
./run-server | slfmt
```
Sample Output:
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
scope: "server/rest_api"
level: "ERROR"
ts: 2025-01-03T08:46:35-06:00 (local) 2025-01-03T14:46:35Z (UTC)
msg: unhandled exception (DbError)
err:
ERROR: relation "users" does not exist
LINE 1: SELECT id FROM users WHERE id = '43422d65-6874-44ce-b9b3-f8c...
^
stack:
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/mummy-0.4.5-cb7f70cd4d6fd3a563e00e664cfbd8cbd3c39b79/mummy.nim(519) workerProc
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/mummy-0.4.5-cb7f70cd4d6fd3a563e00e664cfbd8cbd3c39b79/mummy.nim(450) runTask
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/mummy-0.4.5-cb7f70cd4d6fd3a563e00e664cfbd8cbd3c39b79/mummy/routers.nim(271) :anonymous
/home/username/projects/server/api/src/main/nim/server_api/api.nim(65) :anonymous
/home/username/projects/server/api/src/main/nim/server_api/auth.nim(74) extractSession
/home/username/projects/fiber-orm-nim/src/fiber_orm.nim(599) createOrUpdateUser
/home/username/projects/fiber-orm-nim/src/fiber_orm.nim(384) createOrUpdateRecord
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/db_connector-0.1.0-d68319e3785fa937f0465ea915e942b61b6b5442/db_connector/db_postgres.nim(497) getAllRows
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/db_connector-0.1.0-d68319e3785fa937f0465ea915e942b61b6b5442/db_connector/db_postgres.nim(174) setupQuery
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/db_connector-0.1.0-d68319e3785fa937f0465ea915e942b61b6b5442/db_connector/db_postgres.nim(116) dbError
[[reraised from:
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/mummy-0.4.5-cb7f70cd4d6fd3a563e00e664cfbd8cbd3c39b79/mummy.nim(519) workerProc
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/mummy-0.4.5-cb7f70cd4d6fd3a563e00e664cfbd8cbd3c39b79/mummy.nim(450) runTask
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/mummy-0.4.5-cb7f70cd4d6fd3a563e00e664cfbd8cbd3c39b79/mummy/routers.nim(271) :anonymous
/home/username/projects/server/api/src/main/nim/server_api/api.nim(65) :anonymous
/home/username/projects/server/api/src/main/nim/server_api/auth.nim(74) extractSession
/home/username/projects/fiber-orm-nim/src/fiber_orm.nim(727) createOrUpdateUser
]]
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
scope: "server/rest_api"
level: "ERROR"
ts: 2025-01-03T08:46:35-06:00 (local) 2025-01-03T14:46:35Z (UTC)
msg: unhandled exception (DbError)
err:
ERROR: relation "users" does not exist
LINE 1: SELECT id FROM users WHERE id = '43422d65-6874-44ce-b9b3-f8c...
^
stack:
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/mummy-0.4.5-cb7f70cd4d6fd3a563e00e664cfbd8cbd3c39b79/mummy.nim(519) workerProc
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/mummy-0.4.5-cb7f70cd4d6fd3a563e00e664cfbd8cbd3c39b79/mummy.nim(450) runTask
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/mummy-0.4.5-cb7f70cd4d6fd3a563e00e664cfbd8cbd3c39b79/mummy/routers.nim(271) :anonymous
/home/username/projects/server/api/src/main/nim/server_api/api.nim(65) :anonymous
/home/username/projects/server/api/src/main/nim/server_api/auth.nim(74) extractSession
/home/username/projects/fiber-orm-nim/src/fiber_orm.nim(599) createOrUpdateUser
/home/username/projects/fiber-orm-nim/src/fiber_orm.nim(384) createOrUpdateRecord
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/db_connector-0.1.0-d68319e3785fa937f0465ea915e942b61b6b5442/db_connector/db_postgres.nim(497) getAllRows
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/db_connector-0.1.0-d68319e3785fa937f0465ea915e942b61b6b5442/db_connector/db_postgres.nim(174) setupQuery
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/db_connector-0.1.0-d68319e3785fa937f0465ea915e942b61b6b5442/db_connector/db_postgres.nim(116) dbError
[[reraised from:
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/mummy-0.4.5-cb7f70cd4d6fd3a563e00e664cfbd8cbd3c39b79/mummy.nim(519) workerProc
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/mummy-0.4.5-cb7f70cd4d6fd3a563e00e664cfbd8cbd3c39b79/mummy.nim(450) runTask
/home/username/.local/share/mise/installs/nim/2.2.0/nimble/pkgs2/mummy-0.4.5-cb7f70cd4d6fd3a563e00e664cfbd8cbd3c39b79/mummy/routers.nim(271) :anonymous
/home/username/projects/server/api/src/main/nim/server_api/api.nim(65) :anonymous
/home/username/projects/server/api/src/main/nim/server_api/auth.nim(74) extractSession
/home/username/projects/fiber-orm-nim/src/fiber_orm.nim(727) createOrUpdateUser
]]