Improve resource usage

- Only create json files from scratch if they didn't exists.
- Otherwise update them only once every $IVAL minutes
- Only remove first line and add last line.

mempool.sh

@@ -4,20 +4,30 @@ DESTDIR=/dev/shm/mempool-btc
 BITCOINCLI=/home/bitcoin/bin/bitcoin-cli
 MEMPOOLHOME=/home/mempool/mempool
 TMPFILE=$DESTDIR/rawdump.txt
-
 export DESTDIR MEMPOOLHOME
-mkdir -p $DESTDIR
+
 cd $MEMPOOLHOME
 
+# create ram-disk directory if it does not exists
+if [ ! -e $DESTDIR ]; then
+    mkdir -p $DESTDIR/LOCK
+    # read mempool.log once sequentially to quickly load it in buffers
+    cat mempool.log > /dev/null
+    ./mkdata.sh
+    rmdir $DESTDIR/LOCK
+fi
+
+# create mempool statistics, protected by LOCK
 if ! mkdir $DESTDIR/LOCK 2>/dev/null; then
-  exit
+    exit
 fi
 $BITCOINCLI getrawmempool true > $TMPFILE
 python3 mempool_sql.py < $TMPFILE
 rmdir $DESTDIR/LOCK
 
+# update ram-disk directory, protected by DATALOCK
 if ! mkdir $DESTDIR/DATALOCK 2>/dev/null; then
-  exit
+    exit
 fi
-./mkdata.sh
+./updatedata.sh
 rmdir $DESTDIR/DATALOCK

mkdata.sh

@@ -1,5 +1,7 @@
 #!/bin/bash
 
+# create the JSON files delivering the summarized mempool
+
 MEMPOOL=mempool.log
 
 createfile() {

updatedata.sh

@@ -0,0 +1,47 @@
+#!/bin/bash
+
+# update the JSON files delivering the summarized mempool
+#
+# LINE is set to the last line in mempool.
+# for each file:
+#   check if current minute divisible by IVAL
+#   if divisible:
+#      remove first line (after 'call([').
+#      add LINE to this file (before last line '])').
+
+MEMPOOL=mempool.log
+LINE=`tail -1 $MEMPOOL`
+SECOND=`date +%s`
+MINUTE=`expr $SECOND / 60`
+
+updatefile() {
+  NAME=$1
+  MINUTES=$2
+  IVAL=$3
+  if [ `expr $MINUTE % $IVAL` -eq "0" ]; then
+    (echo 'call(['; tail -n +3 $DESTDIR/$NAME.js | head -n -1; echo "$LINE"; echo '])') > $DESTDIR/$NAME.js.new
+    mv $DESTDIR/$NAME.js.new $DESTDIR/$NAME.js
+  fi
+}
+
+updatefile_all() {
+  NAME=all
+  IVAL=$1
+  if [ `expr $MINUTE % $IVAL` -eq "0" ]; then
+    (head -n -1 $DESTDIR/$NAME.js; echo "$LINE"; echo '])') > $DESTDIR/$NAME.js.new
+    mv $DESTDIR/$NAME.js.new $DESTDIR/$NAME.js
+  fi
+}
+
+updatefile 2h 120 1
+updatefile 8h 480 1
+updatefile 24h 1440 1
+updatefile 2d 2880 2
+updatefile 4d 5760 4
+updatefile 1w 10080 7
+updatefile 2w 20160 14
+updatefile 30d 43200 30
+updatefile 3m 131040 90
+updatefile 6m 262080 180
+updatefile 1y 524160 360
+updatefile_all 360