From 8e4ffe50243fb1acccb58abdb4487e4aa52a0666 Mon Sep 17 00:00:00 2001
From: Nils Gerstner <nils@gerstner.se>
Date: Tue, 15 Nov 2022 10:53:38 +0100
Subject: [PATCH] Add logger

---
 README.md                 |  7 ++--
 bash/logger/README.md     | 25 ++++++++++++++
 bash/logger/controller.sh | 34 +++++++++++++++++++
 bash/logger/logger.sh     | 71 +++++++++++++++++++++++++++++++++++++++
 bash/logger/writer.sh     | 11 ++++++
 5 files changed, 146 insertions(+), 2 deletions(-)
 create mode 100644 bash/logger/README.md
 create mode 100755 bash/logger/controller.sh
 create mode 100755 bash/logger/logger.sh
 create mode 100755 bash/logger/writer.sh

diff --git a/README.md b/README.md
index 7f035a4..cdd9a2e 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,6 @@
-# utils
+# README
 
-Collection of scripts and functions to make my developer life easier.
\ No newline at end of file
+Collection of scripts and functions to make my developer life easier.
+
+**bash/logger**  
+*Enrich command output for logging purposes*
diff --git a/bash/logger/README.md b/bash/logger/README.md
new file mode 100644
index 0000000..1f4af5e
--- /dev/null
+++ b/bash/logger/README.md
@@ -0,0 +1,25 @@
+# LOGGER
+
+Enrich command output for logging purpose.
+This works by  sending stdout and stderr to named pipes.
+The content is read from the pipes and enriched before writing to a file.
+There are three enrichment examples in logger.sh:
+
+- plain text
+- json format
+- systemd journal
+
+## Usage
+
+Add the commands you want to run  in the ./writer.sh file.
+Start the process via ./controller.sh.
+
+``` bash
+./controller.sh
+```
+
+The last command in ./writer.sh ensures that the named pipes get closed and removed in a save way!
+
+``` bash
+echo "quit" >$pipe 2>$err_pipe
+```
diff --git a/bash/logger/controller.sh b/bash/logger/controller.sh
new file mode 100755
index 0000000..309778a
--- /dev/null
+++ b/bash/logger/controller.sh
@@ -0,0 +1,34 @@
+#!/bin/bash
+# Author: Nils Gerstner
+
+#------------- V A R I A B L E S -------------#
+
+LOGFILE="./update.log"
+PID=$$
+pipe=/tmp/out_pipe-$PID
+err_pipe=/tmp/err_pipe-$PID
+
+#--------- G R A C E F U L   E X I T ---------#
+
+trap "rm -f $pipe $err_pipe; pkill -P $PID;" EXIT
+
+#---------- S T A R T   L O G G E R ----------#
+
+# Start logging script
+./logger.sh $pipe $err_pipe |tee -a ./update.log &
+
+# Make sure named pipes have been created
+count=0
+until [[ -p $pipe ]] || [[ -p $err_pipe ]]; do
+    ((count++))
+    if [ $count -gt 100 ]; then break; fi
+    sleep 0.001
+done
+sleep 1
+
+#------------ R U N   S C R I P T ------------#
+
+./writer.sh $pipe $err_pipe
+
+wait
+exit 0
diff --git a/bash/logger/logger.sh b/bash/logger/logger.sh
new file mode 100755
index 0000000..9e589bd
--- /dev/null
+++ b/bash/logger/logger.sh
@@ -0,0 +1,71 @@
+#!/bin/bash
+# Author: Nils Gerstner
+
+pipe="$1"
+err_pipe="$2"
+logfile="$3"
+pid=""
+err_pid=""
+TAB="$(printf '\t')"
+
+trap ">&2 echo 'Logger exiting'; ps -p $pid 2>/dev/null && kill -9 $pid; ps -p $err_pid 2> /dev/null && kill -9 $err_pid; rm -f $err_pipe $pipe 2>&1 > /dev/null" EXIT
+
+if [[ ! -p $pipe ]] || [[ ! -p $err_pipe ]]; then
+    mkfifo $pipe
+    mkfifo $err_pipe
+    while [[ ! -p $pipe ]] && [[ ! -p $err_pipe ]]; do
+        sleep 0.01
+    done
+fi
+
+log() {
+    local named_pipe="$1"
+    local other_pipe="$2"
+    local level="$3"
+
+    while true; do
+        in_msg="$(cat $named_pipe)"
+        if [ -n "$in_msg" ]; then
+            if [[ "$in_msg" == 'quit' ]]; then
+                >&2 echo "stopping $named_pipe"
+                echo "quit" > $other_pipe
+                rm -f $named_pipe
+                break
+            else
+                #----- L O G   E X A M P L E S -----#
+                #
+                # Log to plain text
+                # cat >> "${logfile}_plain" <<< "${level}${TAB}${in_msg}"
+
+                # Log to json file
+                jq -n -c --arg msg "${in_msg}" --arg level "${level}" '{ "level": $level,  "timestamp": (now | strftime("%Y-%m-%d %H:%M:%S")), "message": $msg }' |tee -a $logfile
+
+                # Log to systemd journal
+                # logger -t My-Logger -p ${level,,} "${msg}"
+            fi
+        fi
+    done
+}
+
+log_info(){
+    log $pipe $err_pipe INFO
+}
+
+log_err(){
+    log $err_pipe $pipe  ERROR
+}
+
+while [[ ! -p $pipe ]] || [[ ! -p $err_pipe ]]; do
+    sleep 0.1
+done
+
+log_info & pid="$!"
+log_err & err_pid="$!"
+while [[ -p $pipe ]] && [[ -p $err_pipe ]]; do
+    sleep 0.01
+done
+ps -p $pid && kill -9 $pid
+ps -p $err_pid && kill -9 $err_pid
+
+wait
+exit 0 
diff --git a/bash/logger/writer.sh b/bash/logger/writer.sh
new file mode 100755
index 0000000..d693c85
--- /dev/null
+++ b/bash/logger/writer.sh
@@ -0,0 +1,11 @@
+#!/bin/bash
+# Author: Nils Gerstner
+
+pipe=$1
+err_pipe=$2
+
+echo "$$ The time is $(date)" >$pipe 2>$err_pipe
+edf "$$ The time is $(date)" >$pipe 2>$err_pipe
+ls |tail -n1 >$pipe 2>$err_pipe 
+echo "$$ The time is $(date)" 2>$err_pipe
+echo "quit" >$pipe 2>$err_pipe