🆕 retry git push & pull

Retry git push & pull operations.
Under poor network, these operations may fail due to connection error.

bin/gister

@@ -467,6 +467,21 @@ is_dirty() {
  fi
 }
 
+retry_three_times() {
+ local retry_command="$1"
+
+ # fibonacci backoff
+ local first_retry="$retry_command || (sleep 2; $retry_command)"
+ local second_retry="($first_retry) || (sleep 8; $retry_command)"
+ local third_retry="($second_retry) || (sleep 34; $retry_command)"
+
+ eval "$third_retry"
+}
+
+retry_git() {
+ retry_three_times "git $1 >/dev/null"
+}
+
 sync_gist() {
  local gist_id=$1
  local gist_updated_at=$2
@@ -476,6 +491,7 @@ sync_gist() {
  cd $gisthome/tree/$gist_id
  # Compare update time to skip already up to date repos.
  # This will speed sync on slow network connection.
+ # This may contain a bug if the gist is updated by someone else, e.g. forking.
  local last_commit_unixtime=$(git log -1 --pretty=format:%ct)
  local last_updated_unixtime=$($DATE --date="$gist_updated_at" +"%s")
  local time_difference=$(($last_commit_unixtime - $last_updated_unixtime))
@@ -492,22 +508,26 @@ sync_gist() {
  else
  echo "DIRTY $gist_id, auto committing"
  git add . && git commit -m "automated update" &&
- git pull > /dev/null && git push > /dev/null
+ retry_git pull && retry_git push > /dev/null
  fi
  else
- git pull > /dev/null && git push > /dev/null
+ retry_git pull && retry_git push > /dev/null
  fi
  fi
  elif [ $gist_type = "starred" ]; then
  if (is_dirty); then
  echo "DIRTY $gist_id"
  else
- git pull > /dev/null
+ retry_git pull
  fi
  else
  echo "You have encountered a bug."
  echo "Please report it at https://github.com/weakish/gister/issues"
  fi
+ else
+ if [ -n $GISTER_DEBUG ]; then
+ echo "SKIPPED $gist_id (up to date)"
+ fi
  fi
  else
  cd $gisthome/tree