Logging
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Description
Thenpm CLI has various mechanisms for showing different levels of information back to end-users for certain commands, configurations & environments.
Setting Log File Location
All logs are written to a debug log, with the path to that file printed if the execution of a command fails.
The default location of the logs directory is a directory named_logs inside the npm cache. This can be changed with thelogs-dir config option.
For example, if you wanted to write all your logs to the current working directory, you could run:npm install --logs-dir=.. This is especially helpful in debugging a specificnpm issue as you can run a command multiple times with different config values and then diff all the log files.
Log files will be removed from thelogs-dir when the number of log files exceedslogs-max, with the oldest logs being deleted first.
To turn off logs completely set--logs-max=0.
Setting Log Levels
loglevel
loglevel is a global argument/config that can be set to determine the type of information to be displayed.
The default value ofloglevel is"notice" but there are several levels/types of logs available, including:
"silent""error""warn""notice""http""info""verbose""silly"
All logs pertaining to a level preceding the current setting will be shown.
Aliases
The log levels listed above have various corresponding aliases, including:
-d:--loglevel info--dd:--loglevel verbose--verbose:--loglevel verbose--ddd:--loglevel silly-q:--loglevel warn--quiet:--loglevel warn-s:--loglevel silent--silent:--loglevel silent
foreground-scripts
Thenpm CLI began hiding the output of lifecycle scripts fornpm install as ofv7. Notably, this means you will not see logs/output from packages that may be using "install scripts" to display information back to you or from your own project's scripts defined inpackage.json. If you'd like to change this behavior & log this output you can setforeground-scripts totrue.
Timing Information
The--timing config can be set which does a few things:
- Always shows the full path to the debug log regardless of command exit status
- Write timing information to a process specific timing file in the cache or
logs-dir - Output timing information to the terminal
This file contains atimers object where the keys are an identifier for the portion of the process being timed and the value is the number of milliseconds it took to complete.
Sometimes it is helpful to get timing information without outputting anything to the terminal. For example, the performance might be affected by writing to the terminal. In this case you can use--timing --silent which will still write the timing file, but not output anything to the terminal while running.
Registry Response Headers
npm-notice
Thenpm CLI reads from & logs anynpm-notice headers that are returned from the configured registry. This mechanism can be used by third-party registries to provide useful information when network-dependent requests occur.
This header is not cached, and will not be logged if the request is served from the cache.
Logs and Sensitive Information
Thenpm CLI makes a best effort to redact the following from terminal output and log files:
- Passwords inside basic auth URLs
- npm tokens
However, this behavior should not be relied on to keep all possible sensitive information redacted. If you are concerned about secrets in your log file or terminal output, you can use--loglevel=silent and--logs-max=0 to ensure no logs are written to your terminal or filesystem.
