man/systemd.journal-fields.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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   6   This file is part of systemd.
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   8   Copyright 2010 Lennart Poettering
   9
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  23
  24 <refentry id="systemd.journal-fields">
  25
  26         <refentryinfo>
  27                 <title>systemd.journal-fields</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>systemd.journal-fields</refentrytitle>
  42                 <manvolnum>7</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>systemd.journal-fields</refname>
  47                 <refpurpose>Special journal fields</refpurpose>
  48         </refnamediv>
  49
  50         <refsect1>
  51                 <title>Description</title>
  52
  53                 <para>Entries in the journal resemble an environment
  54                 block in their syntax, however with fields that can
  55                 include binary data. Primarily, fields are formatted
  56                 UTF-8 text strings, and binary formatting is used only
  57                 where formatting as UTF-8 text strings makes little
  58                 sense. New fields may freely be defined by
  59                 applications, but a few fields have special
  60                 meaning. All fields with special meanings are
  61                 optional.</para>
  62         </refsect1>
  63
  64         <refsect1>
  65                 <title>User Journal Fields</title>
  66
  67                 <para>User fields are fields that are directly passed
  68                 from clients and stored in the journal.</para>
  69
  70                 <variablelist>
  71                         <varlistentry>
  72                                 <term>MESSAGE=</term>
  73                                 <listitem>
  74                                         <para>The human readable
  75                                         message string for this
  76                                         entry. This is supposed to be
  77                                         the primary text shown to the
  78                                         user. It is usually not
  79                                         translated (but might be in
  80                                         some cases), and is not
  81                                         supposed to be parsed for meta
  82                                         data.</para>
  83                                 </listitem>
  84                         </varlistentry>
  85
  86                         <varlistentry>
  87                                 <term>MESSAGE_ID=</term>
  88                                 <listitem>
  89                                         <para>A 128bit message
  90                                         identifier ID for recognizing
  91                                         certain message types, if this
  92                                         is desirable. This should
  93                                         contain a 128bit id formatted
  94                                         as lower-case hexadecimal
  95                                         string, without any separating
  96                                         dashes or suchlike. This is
  97                                         recommended to be a UUID
  98                                         compatible ID, but this is not
  99                                         enforced, and formatted
 100                                         differently. Developers can
 101                                         generate a new ID for this
 102                                         purpose with
 103                                         <command>journalctl
 104                                         --new-id</command>.</para>
 105                                 </listitem>
 106                         </varlistentry>
 107
 108                         <varlistentry>
 109                                 <term>PRIORITY=</term>
 110                                 <listitem>
 111                                         <para>A priority value between
 112                                         0 (<literal>emerg</literal>)
 113                                         and 7
 114                                         (<literal>debug</literal>)
 115                                         formatted as decimal
 116                                         string. This field is
 117                                         compatible with syslog's
 118                                         priority concept.</para>
 119                                 </listitem>
 120                         </varlistentry>
 121
 122                         <varlistentry>
 123                                 <term>CODE_FILE=</term>
 124                                 <term>CODE_LINE=</term>
 125                                 <term>CODE_FUNC=</term>
 126                                 <listitem>
 127                                         <para>The code location
 128                                         generating this message, if
 129                                         known. Contains the source
 130                                         file name, the line number and
 131                                         the function name.</para>
 132                                 </listitem>
 133                         </varlistentry>
 134
 135                         <varlistentry>
 136                                 <term>SYSLOG_FACILITY=</term>
 137                                 <term>SYSLOG_IDENTIFIER=</term>
 138                                 <term>SYSLOG_PID=</term>
 139                                 <listitem>
 140                                         <para>Syslog compatibility
 141                                         fields containing the facility
 142                                         (formatted as decimal string),
 143                                         the identifier string
 144                                         (i.e. "tag"), and the client
 145                                         PID.</para>
 146                                 </listitem>
 147
 148                         </varlistentry>
 149                 </variablelist>
 150         </refsect1>
 151
 152         <refsect1>
 153                 <title>Trusted Journal Fields</title>
 154
 155                 <para>Fields prefixed with an underscore are trusted
 156                 fields, i.e. fields that are implicitly added by the
 157                 journal and cannot be altered by client code.</para>
 158
 159                 <variablelist>
 160                         <varlistentry>
 161                                 <term>_PID=</term>
 162                                 <term>_UID=</term>
 163                                 <term>_GID=</term>
 164                                 <listitem>
 165                                         <para>The process, user and
 166                                         group ID of the process the
 167                                         journal entry originates from
 168                                         formatted as decimal
 169                                         string.</para>
 170                                 </listitem>
 171                         </varlistentry>
 172
 173                         <varlistentry>
 174                                 <term>_COMM=</term>
 175                                 <term>_EXE=</term>
 176                                 <term>_CMDLINE=</term>
 177                                 <listitem>
 178                                         <para>The name, the executable
 179                                         path and the command line of
 180                                         the process the journal entry
 181                                         originates from.</para>
 182                                 </listitem>
 183                         </varlistentry>
 184
 185                         <varlistentry>
 186                                 <term>_AUDIT_SESSION=</term>
 187                                 <term>_AUDIT_LOGINUID=</term>
 188                                 <listitem>
 189                                         <para>The session and login
 190                                         UID of the process the journal
 191                                         entry originates from, as
 192                                         maintained by the kernel audit
 193                                         subsystem.</para>
 194                                 </listitem>
 195                         </varlistentry>
 196
 197                         <varlistentry>
 198                                 <term>_SYSTEMD_CGROUP=</term>
 199                                 <term>_SYSTEMD_SESSION=</term>
 200                                 <term>_SYSTEMD_UNIT=</term>
 201                                 <term>_SYSTEMD_OWNER_UID=</term>
 202
 203                                 <listitem>
 204                                         <para>The contol group path in
 205                                         the systemd hierarchy, the
 206                                         systemd session ID (if any),
 207                                         the systemd unit name (if any)
 208                                         and the owner UID of the
 209                                         systemd session (if any) of
 210                                         the process the journal entry
 211                                         originates from.</para>
 212                                 </listitem>
 213                         </varlistentry>
 214
 215                         <varlistentry>
 216                                 <term>_SELINUX_CONTEXT=</term>
 217                                 <listitem>
 218                                         <para>The SELinux security
 219                                         context of the process the
 220                                         journal entry originates
 221                                         from.</para>
 222                                 </listitem>
 223                         </varlistentry>
 224
 225                         <varlistentry>
 226                                 <term>_SOURCE_REALTIME_TIMESTAMP=</term>
 227                                 <listitem>
 228                                         <para>The earliest trusted
 229                                         timestamp of the message, if
 230                                         any is known that is different
 231                                         from the reception time of the
 232                                         journal. This is the time in
 233                                         usec since the epoch UTC
 234                                         formatted as decimal
 235                                         string.</para>
 236                                 </listitem>
 237                         </varlistentry>
 238
 239                         <varlistentry>
 240                                 <term>_BOOT_ID=</term>
 241                                 <listitem>
 242                                         <para>The kernel boot ID for
 243                                         the boot the message was
 244                                         generated in, formatted as
 245                                         128bit hexadecimal
 246                                         string.</para>
 247                                 </listitem>
 248                         </varlistentry>
 249
 250                         <varlistentry>
 251                                 <term>_MACHINE_ID=</term>
 252                                 <listitem>
 253                                         <para>The machine ID of the
 254                                         originating host, as available
 255                                         in
 256                                         <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 257                                 </listitem>
 258                         </varlistentry>
 259
 260                         <varlistentry>
 261                                 <term>_HOSTNAME=</term>
 262                                 <listitem>
 263                                         <para>The name of the
 264                                         originating host.</para>
 265                                 </listitem>
 266                         </varlistentry>
 267
 268                         <varlistentry>
 269                                 <term>_TRANSPORT=</term>
 270                                 <listitem>
 271                                         <para>How the entry was
 272                                         received by the journal
 273                                         service. One of
 274                                         <literal>driver</literal>,
 275                                         <literal>syslog</literal>,
 276                                         <literal>journal</literal>,
 277                                         <literal>stdout</literal>,
 278                                         <literal>kernel</literal> for
 279                                         internally generated messages,
 280                                         for those received via the
 281                                         local syslog socket with the
 282                                         syslog protocol, for those
 283                                         received via the native
 284                                         journal protocol, for the
 285                                         those read from a services'
 286                                         standard output or error
 287                                         output, and for those read
 288                                         from the kernel, resp.
 289                                         </para>
 290                                 </listitem>
 291                         </varlistentry>
 292                 </variablelist>
 293         </refsect1>
 294
 295         <refsect1>
 296                 <title>Address Fields</title>
 297
 298                 <para>During serialization into external formats the
 299                 addresses of journal entries are serialized into
 300                 fields prefixed with double underscores. Note that
 301                 these aren't proper fields when stored in the journal,
 302                 but addressing meta data of entries. They cannot be
 303                 written as part of structured log entries via calls
 304                 such as
 305                 <citerefentry><refentrytitle>sd_journal_send</refentrytitle><manvolnum>3</manvolnum></citerefentry>. They
 306                 may also not be used as matches for
 307                 <citerefentry><refentrytitle>sd_journal_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry></para>
 308
 309                 <variablelist>
 310                         <varlistentry>
 311                                 <term>__CURSOR=</term>
 312                                 <listitem>
 313                                         <para>The cursor for the
 314                                         entry. A cursor is an opaque
 315                                         text string that uniquely
 316                                         describes the position of an
 317                                         entry in the journal and is
 318                                         portable across machines,
 319                                         platforms and journal
 320                                         files.</para>
 321                                 </listitem>
 322                         </varlistentry>
 323
 324                         <varlistentry>
 325                                 <term>__REALTIME_TIMESTAMP=</term>
 326                                 <listitem>
 327                                         <para>The wallclock time
 328                                         (CLOCK_REALTIME) at the point
 329                                         in time the entry was received
 330                                         by the journal, in usec since
 331                                         the epoch UTC formatted as
 332                                         decimal string. This has
 333                                         different properties from
 334                                         <literal>_SOURCE_REALTIME_TIMESTAMP=</literal>
 335                                         as it is usually a bit later
 336                                         but more likely to be
 337                                         monotonic.</para>
 338                                 </listitem>
 339                         </varlistentry>
 340
 341                         <varlistentry>
 342                                 <term>__MONOTONIC_TIMESTAMP=</term>
 343                                 <listitem>
 344                                         <para>The monotonic time
 345                                         (CLOCK_MONOTONIC) at the point
 346                                         in time the entry was received
 347                                         by the journal in usec
 348                                         formatted as decimal
 349                                         string. To be useful as an
 350                                         address for the entry this
 351                                         should be combined with with
 352                                         boot ID in
 353                                         <literal>_BOOT_ID=</literal>.</para>
 354                                 </listitem>
 355                         </varlistentry>
 356                 </variablelist>
 357         </refsect1>
 358
 359         <refsect1>
 360                   <title>See Also</title>
 361                   <para>
 362                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 363                           <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 364                           <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 365                           <citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 366                   </para>
 367         </refsect1>
 368
 369 </refentry>