Add common bash functions to help track metrics.

Add a bash library that has several functions that can
be used within TOCI to track simple metrics (and eventually)
load them into a graphite server as time series data.

The record_metric function can be used to store any metric
in the configured data file.

The start_metric/stop_metric functions are used to store and
calculate the total time a task tasks. These functions can be
called in a nested fashion such that timestamps within timestamps
can be tracked and recorded.

The metrics_to_graphite function is meant to be called after all metrics
have been recorded. It will also reset the data so it isn't posted
to graphite twice (should you choose to batch this).

Change-Id: I35228ec61b4c6c468b277ff48bf57872a5b24362

scripts/metrics.bash

@@ -0,0 +1,67 @@
+export METRICS_START_TIMES=/tmp/metric-start-times
+export METRICS_DATA_FILE=/tmp/metrics-data
+
+# Record a metric. If no DTS is provided the current date is used.
+function record_metric {
+    local METRIC_NAME=$1
+    local METRIC_VALUE=$2
+    local DTS=${3:-$(date +%s)}
+    if [ -z "$METRIC_NAME" -o -z "$METRIC_VALUE" ]; then
+        echo "Please specify METRIC_NAME and METRIC_VALUE" >&2
+        exit 1
+    fi
+    echo "$METRIC_NAME:$METRIC_VALUE:$DTS" >> $METRICS_DATA_FILE
+}
+
+# Start a time metric by keeping track of a timestamp until stop_metric is
+# called. NOTE: time metrics names must be unique.
+function start_metric {
+    local NAME=$1
+    local START_TIME=$(date +%s)
+    # we use : as our delimiter so convert to _. Also convert spaces and /'s.
+    local METRIC_NAME=$(echo "$1" | sed -e 's|[\ \///:]|_|g')
+
+    if grep -c "^$METRIC_NAME:" $METRICS_START_TIMES &>/dev/null; then
+        echo "start_metric has already been called for $NAME" >&2
+        exit 1
+    fi
+    echo "$METRIC_NAME:$START_TIME" >> $METRICS_START_TIMES
+
+}
+
+# Stop a time metric previously started by the start_metric function.
+# The total time (in seconds) is calculated and logged to the metrics
+# data file. NOTE: the end time is used as the DTS.
+function stop_metric {
+    local NAME=$1
+    local METRIC_NAME=$(echo "$1" | sed -e 's|[\ \///:]|_|g')
+    local END_TIME=$(date +%s)
+    if ! grep -c "^$METRIC_NAME" $METRICS_START_TIMES &>/dev/null; then
+        echo "Please call start_metric before calling stop_metric for $NAME" >&2
+        exit 1
+    fi
+    local LINE=$(grep "^$METRIC_NAME:" $METRICS_START_TIMES)
+    local START_TIME=$(grep "^$METRIC_NAME:" $METRICS_START_TIMES | cut -d ':' -f '2')
+    local TOTAL_TIME="$(($END_TIME - $START_TIME))"
+    record_metric "$METRIC_NAME" "$TOTAL_TIME" "$END_TIME"
+
+}
+
+function metrics_to_graphite {
+    local SERVER=$1
+    local PORT=${2:-2003} # default port for graphite data
+
+    local METRIC_NAME
+    local METRIC_VAL
+    local DTS
+
+    for X in $(cat $METRICS_DATA_FILE); do
+        METRIC_NAME=$(echo $X | cut -d ":" -f 1)
+        METRIC_VAL=$(echo $X | cut -d ":" -f 2)
+        DTS=$(echo $X | cut -d ":" -f 3)
+        echo "$METRIC_NAME $METRIC_VAL $DTS" | nc ${SERVER} ${PORT}
+    done
+    # reset the existing data file and start times
+    echo "" > METRICS_START_TIMES
+    echo "" > METRICS_DATA_FILE
+}