1LOGGING(7)                                                          LOGGING(7)
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NAME

6       Logging - Why, What & How We Log
7
8   Description
9       The  npm CLI has various mechanisms for showing different levels of in‐
10       formation back to end-users for certain commands, configurations &  en‐
11       vironments.
12
13   Setting Log File Location
14       All logs are written to a debug log, with the path to that file printed
15       if the execution of a command fails.
16
17       The default location of the logs directory is a directory  named  _logs
18       inside  the npm cache. This can be changed with the logs-dir config op‐
19       tion.
20
21       For example, if you wanted to write all your logs to the current  work‐
22       ing  directory,  you could run: npm install --logs-dir=.. This is espe‐
23       cially helpful in debugging a specific npm issue as you can run a  com‐
24       mand  multiple times with different config values and then diff all the
25       log files.
26
27       Log files will be removed from the logs-dir  when  the  number  of  log
28       files exceeds logs-max, with the oldest logs being deleted first.
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30       To turn off logs completely set --logs-max=0.
31
32   Setting Log Levels
33   loglevel
34       loglevel  is  a global argument/config that can be set to determine the
35       type of information to be displayed.
36
37       The default value of loglevel is "notice" but there  are  several  lev‐
38       els/types of logs available, including:
39
40       •   "silent"
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42       •   "error"
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44       •   "warn"
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46       •   "notice"
47
48       •   "http"
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50       •   "info"
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52       •   "verbose"
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54       •   "silly"
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56
57       All  logs  pertaining to a level proceeding the current setting will be
58       shown.
59
60   Aliases
61       The log levels listed above have various corresponding aliases, includ‐
62       ing:
63
64       •   -d: --loglevel info
65
66       •   --dd: --loglevel verbose
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68       •   --verbose: --loglevel verbose
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70       •   --ddd: --loglevel silly
71
72       •   -q: --loglevel warn
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74       •   --quiet: --loglevel warn
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76       •   -s: --loglevel silent
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78       •   --silent: --loglevel silent
79
80
81   foreground-scripts
82       The  npm  CLI  began hiding the output of lifecycle scripts for npm in‐
83       stall as of v7. Notably, this means you will not see  logs/output  from
84       packages  that  may  be  using "install scripts" to display information
85       back to you or from your own project's scripts defined in package.json.
86       If  you'd  like  to  change this behavior & log this output you can set
87       foreground-scripts to true.
88
89   Timing Information
90       The --timing config ⟨/using-npm/config#timing⟩ can be set which does  a
91       few things:
92
93       1.  Always  shows  the full path to the debug log regardless of command
94           exit status
95
96       2.  Write timing information to a process specific timing file  in  the
97           cache or logs-dir
98
99       3.  Output timing information to the terminal
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101
102       This file contains a timers object where the keys are an identifier for
103       the portion of the process being timed and the value is the  number  of
104       milliseconds it took to complete.
105
106       Sometimes  it  is  helpful to get timing information without outputting
107       anything to the terminal. For example, the  performance  might  be  af‐
108       fected  by  writing  to the terminal. In this case you can use --timing
109       --silent which will still write the timing file, but  not  output  any‐
110       thing to the terminal while running.
111
112   Registry Response Headers
113   npm-notice
114       The  npm CLI reads from & logs any npm-notice headers that are returned
115       from the configured registry. This mechanism can be used by third-party
116       registries  to  provide  useful  information when network-dependent re‐
117       quests occur.
118
119       This header is not cached, and will not be logged  if  the  request  is
120       served from the cache.
121
122   Logs and Sensitive Information
123       The  npm  CLI makes a best effort to redact the following from terminal
124       output and log files:
125
126       •   Passwords inside basic auth URLs
127
128       •   npm tokens
129
130
131       However, this behavior should not be relied on  to  keep  all  possible
132       sensitive  information  redacted. If you are concerned about secrets in
133       your log file or terminal output, you  can  use  --loglevel=silent  and
134       --logs-max=0 to ensure no logs are written to your terminal or filesys‐
135       tem.
136
137   See also
138       •   npm help config
139
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142                                 November 2023                      LOGGING(7)