From 57d439aab95d51c55abf826441f82d8264ad6c22 Mon Sep 17 00:00:00 2001
From: Shizun Ge <shizunge@gmail.com>
Date: Thu, 18 Jan 2024 18:37:50 -0800
Subject: [PATCH] [entrypoint] exclude the time spent on updating from sleep
 seconds.

---
 README.md         |  2 +-
 src/entrypoint.sh | 18 +++++++++++-------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/README.md b/README.md
index 610fb5e..3ee24cc 100644
--- a/README.md
+++ b/README.md
@@ -32,7 +32,7 @@ You can configure the most behaviors of *Gantry* via environment variables.
 | GANTRY_NODE_NAME      |      | Add node name to logs. |
 | GANTRY_POST_RUN_CMD   |      | Command(s) to eval after each updating iteration. |
 | GANTRY_PRE_RUN_CMD    |      | Command(s) to eval before each updating iteration. |
-| GANTRY_SLEEP_SECONDS  | 0    | Sleep time between two updates. Set it to 0 to run *Gantry* once and then exit. |
+| GANTRY_SLEEP_SECONDS  | 0    | Interval between two updates. Set it to 0 to run *Gantry* once and then exit. Sleep time will exclude the time spent on updating services. |
 | TZ                    |      | Set timezone for time in logs. |
 
 ### To login to registries
diff --git a/src/entrypoint.sh b/src/entrypoint.sh
index d3799c4..6e57b7a 100755
--- a/src/entrypoint.sh
+++ b/src/entrypoint.sh
@@ -129,22 +129,26 @@ main() {
   LOG_LEVEL="${GANTRY_LOG_LEVEL:-${LOG_LEVEL}}"
   NODE_NAME="${GANTRY_NODE_NAME:-${NODE_NAME}}"
   export LOG_LEVEL NODE_NAME
-  local SLEEP_SECONDS="${GANTRY_SLEEP_SECONDS:-0}"
+  local INTERVAL_SECONDS="${GANTRY_SLEEP_SECONDS:-0}"
   if ! is_number "${SLEEP_SECONDS}"; then 
     log ERROR "GANTRY_SLEEP_SECONDS must be a number. Got \"${GANTRY_SLEEP_SECONDS}\"."
     return 1;
   fi
   local STACK="${1:-gantry}"
   local RETURN_VALUE=0
+  local START_TIME PASSED_SECONDS SLEEP_SECONDS
   while true; do
-    # SC2034 (warning): LOG_SCOPE appears unused. Verify use (or export if used externally).
-    # shellcheck disable=SC2034
-    LOG_SCOPE="${STACK}"
+    export LOG_SCOPE="${STACK}"
+    START_TIME=$(date +%s)
     gantry "${@}"
     RETURN_VALUE=$?
-    [ "${SLEEP_SECONDS}" -le 0 ] && break;
-    log INFO "Sleeping ${SLEEP_SECONDS} seconds before next update."
-    sleep "${SLEEP_SECONDS}"
+    [ "${INTERVAL_SECONDS}" -le 0 ] && break;
+    PASSED_SECONDS=$(difference_between "${START_TIME}" "$(date +%s)")
+    SLEEP_SECONDS=$((INTERVAL_SECONDS - PASSED_SECONDS))
+    if [ "${SLEEP_SECONDS}" -gt 0 ]; then
+      log INFO "Sleeping ${SLEEP_SECONDS} seconds before next update."
+      sleep "${SLEEP_SECONDS}"
+    fi
   done
   return ${RETURN_VALUE}
 }