lnav/example-scripts/log_to_csv.sh

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#!/usr/bin/env bash
#
# An example script that converts messages in a syslog file into a
# CSV-formatted file. The CSV file is written to the current directory
# with the same base name as the source file. If the script is run on
# the same file multiple times, it will only convert newly added lines.
#
# NOTE: lnav is going to save some state in $HOME; you might want to change
# $HOME to something else...
#
# NOTE 2: Unfortunately, this is pretty inefficient right now since lnav
# is going to store the entire log file in memory when processing the
# result of the SQL SELECT.
#
if test $# -lt 1; then
echo "usage: $0 <path>"
echo "Convert a syslog file into CSV format."
exit 1
fi
if test ! -f "$1"; then
echo "error: expecting a log file as the first argument"
exit 1
fi
# Figure out a unique file name.
out_file_base=$(basename "$1")
counter=0
while test -e "${out_file_base}.${counter}.csv"; do
counter=$((counter + 1))
done
export OUT_FILE="${out_file_base}.${counter}.csv"
# Here's a quick summary of what this is doing:
#
# 1. ':load-session' will load the session data which stores which lines
# are bookmarked in a file. We're using bookmarks to keep track of the
# last line that we converted in a previous run of this script.
# 2. ';CREATE TABLE helper' creates a temporary table that we use to store
# the range of messages that we'll be converting.
# 3. ';INSERT INTO helper' will figure out the range of lines in syslog file
# to convert.
# 4. ';UPDATE syslog_log' will set a bookmark on the last line of the range
# we computed in the previous step.
# 5. ';SELECT *' will pull all of the log messages in the computed range.
# 6. ':write-csv-to' will write out the log messages SELECTed in step #5.
# 7. ':save-session' will save the bookmark we set so it can be loaded on
# future runs of this script.
lnav -nq -d /tmp/lnav.err \
-c ":load-session" \
-c ";CREATE TABLE helper ( start_line int, max_line int )" \
-c ";INSERT INTO helper ( start_line, max_line ) VALUES (\
(SELECT coalesce(\
(SELECT max(log_line) FROM syslog_log where log_mark = 1) + 1,\
0)),\
(SELECT max(log_line) FROM syslog_log ))" \
-c ";UPDATE syslog_log SET log_mark = 1 where log_line = (\
SELECT max_line FROM helper)" \
-c ";SELECT *,log_text FROM syslog_log where log_line between (\
SELECT start_line FROM helper) and (SELECT max_line FROM helper)" \
-c ':write-csv-to $OUT_FILE' \
-c ":save-session" \
"$1"