package tezos-stdlib-unix

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An implementation of Tezos_base.Internal_event.SINK which writes the events as JSON or pretty printed into a single file-descriptor.

It is registered with the URI scheme "file-descriptor-path" to output to a file or "file-descriptor-stdout"/"file-descriptor-stderr" for stdout and stderr respectively.

Available options are

  • "level-at-least" the minimal log-level that the sink will output (see Tezos_event_logging.Internal_event.level).
  • "section-prefix" can be given many times and defines a list of pairs "<section-prefix>:<level-threshold>" which can be used to setup more precise filters. "level-at-least=info" is understood as "section-prefix=:info" (the empty section prefix matches all sections). To exclude completely a section from the log stream that the sink will output, you can use the special level-threshold "none".
  • "format" the output format used; acceptable values are "one-per-line" (the default), "netstring" (see The Netstring format) (both to separate JSON records), or "pp" to output the events pretty-printed as text using the syslog format.

Options available only for "file-descriptor-path://":

  • "with-pid=true" adds the current process id to the file path provided.
  • "fresh=true" smashes the content of the file if it already exists instead of appending to it.
  • "chmod=<INT>" sets the access-rights of the file at creation time (default is 0o600, provided umask allows it).


  • export TEZOS_EVENTS_CONFIG="file-descriptor-path:///the/path/to/write.log?format=one-per-line&section-prefix=p2p.maintenance:none&with-pid=true&chmod=0o640": By default all executables will write all log events of level at least Info to a file "/the/path/to/write-XXXX.log" where "XXXX" is the process ID, the file will be also readable by the user's group (0o640). The maintenance module will be excluded from the stream.
  • export TEZOS_EVENTS_CONFIG="file-descriptor-path:///the/path/to/write.log?section-prefix=rpc:debug&section-prefix=validator:debug&section-prefix=:none": Write only sections validator and rpc at debug level but exclude all other sections from the stream.
  • export TEZOS_EVENTS_CONFIG="file-descriptor-path:///the/path/to/write.log?format=one-per-line&level-at-least=notice&with-pid=true&chmod=0o640": Executables will write all log events of level at least Notice to a file "/the/path/to/write-XXXX.log" where "XXXX" is the process ID, the file will be also readable by the user's group (0o640).
  • "export TEZOS_EVENTS_CONFIG=file-descriptor-stderr://?format=netstring" Executables will write to stderr.
  • export TEZOS_EVENTS_CONFIG="file-descriptor-path:///dev/fd/4?format=netstring" Executables will write to the 4 file-descriptor likely opened by a parent monitoring process (non-standard feature available on mainstream UNIX hosts, e.g. Linux and MacOSX).
  • export TEZOS_EVENT_HOSTNAME="hostname" The hostname will be used in the JSON representation of the event. By default, it is the hostname given by Unix.gethostname ().
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