From 55adf433bd4488de5a16dd31a30895cf1dc24bab Mon Sep 17 00:00:00 2001
From: Fred Hamster <fred@gruntose.com>
Date: Mon, 16 Dec 2024 19:27:52 -0500
Subject: [PATCH] isolated tri-script remote launching in own script

---
 scripts/core/remote_instigater.sh             | 113 ++++++++++++++++++
 .../fred/scripts/jobby/uva_strider.sh         |   3 -
 2 files changed, 113 insertions(+), 3 deletions(-)
 create mode 100644 scripts/core/remote_instigater.sh

diff --git a/scripts/core/remote_instigater.sh b/scripts/core/remote_instigater.sh
new file mode 100644
index 00000000..57926fde
--- /dev/null
+++ b/scripts/core/remote_instigater.sh
@@ -0,0 +1,113 @@
+#!/usr/bin/env bash
+
+# implements an approach for striding a set of hosts with a local init
+# method, a remote action method, and a local clean-up method.
+
+source "$FEISTY_MEOW_SCRIPTS/core/launch_feisty_meow.sh"
+
+# documentation...
+function print_instructions()
+{
+  echo "
+$(basename $0 .sh): runs a remote action on a set of hosts.
+
+This script needs at least four parameters:
+
+1) The initialization script, which will run locally before each host action.
+This script must take at least a single parameter, which is the hostname,
+although it does not need to do anything with that if it's not useful for
+initialization.
+2) The actual remote action script, which will run on the remote hosts.
+This script needs to be self-contained enough to handle doing its job on the
+remote side with a minimum of setup--only what's already configured on the
+remote host will be available to the script.
+3) The clean-up script, which will run locally after a successful remote
+action.  This script also needs to accept at least a hostname parameter.
+4) The hostname to run the script on, or a domain name when used with a set
+of hosts.
+5) The set of hosts, if a domain name is provided.  Otherwise, there are only
+four parameters.  Note that if this parameter is provided, it may contain
+multiple hosts, but they must be included in this single parameter.  See the
+examples below for more info.
+
+Examples:
+
+$(basename $0 .sh) \$HOME/my_init.sh \$HOME/my_remote_actor.sh \$HOME/my_cleaner.sh singlehost.mydomain.org
+   # invokes the remote script on a single host.
+
+$(basename $0 .sh) \$HOME/my_init.sh \$HOME/my_remote_actor.sh \$HOME/my_cleaner.sh mydomain.org \"thathost1 thathost2 thathost3\"
+   # invokes the remote script on multiple hosts.
+"
+}
+
+# takes a triplet of script names and runs them on local and remote hosts...
+# first the initialization operation is run locally, then the actual remote
+# operation is invoked (remotely), then the clean-up operation is run locally.
+# the initialization and clean-up operations are expected to take a hostname,
+# and they will each be run for each remote host.
+function instigate_remote_calls()
+{
+  local init_op="$1"; shift
+  local remote_op="$1"; shift
+  local cleanup_op="$1"; shift
+  local domain_piece="$1"; shift
+  local host_list="$1"; shift
+  # variables used later.
+  local retval
+
+  for host in $host_list; do
+
+    # first we call our initialization process.
+    echo "invoking local initialization operation '$init_op'..."
+    squelch_unless_error bash "$init_op" "${host}.${domain_piece}"
+    retval=$?
+    if [ $retval -ne 0 ]; then
+      echo "got return value $retval from initialization script '$init_op' for ${host}.${domain_piece}; skipping it."
+      continue
+    fi
+
+    # now we make the remote call by relying on the host strider.
+    echo "invoking remote action operation '$remote_op'..."
+    squelch_unless_error bash $FEISTY_MEOW_SCRIPTS/core/host_strider.sh "${remote_op}" "${domain_piece}" "${host}"
+    retval=$?
+    if [ $retval -ne 0 ]; then
+      echo "got return value $retval from remote action script '$remote_op' on ${host}.${domain_piece}; skipping it."
+      continue
+    fi
+
+    # then invoke the clean-up call to get things right again on the local host.
+    echo "invoking local clean-up operation '$cleanup_op'..."
+    squelch_unless_error bash "$cleanup_op" "${host}.${domain_piece}"
+    retval=$?
+    if [ $retval -ne 0 ]; then
+      echo "got return value $retval from clean-up script '$cleanup_op' for ${host}.${domain_piece}; skipping it."
+      continue
+    fi
+
+  done
+}
+
+################
+
+# active part of the script, where we go out to a bunch of machines to get things done.
+
+################
+
+init_op="$1"; shift
+remote_op="$1"; shift
+cleanup_op="$1"; shift
+domain_piece="$1"; shift
+host_piece="$1"; shift
+
+if [ -z "$init_op" -o -z "$remote_op" -o -z "$cleanup_op" -o -z "$domain_piece" ]; then
+  print_instructions
+  exit 1
+fi
+
+################
+
+# if we made it to here, let's try doing their action on all those hosts they provided...
+instigate_remote_calls "$init_op" "$remote_op" "$cleanup_op" "$domain_piece" "$host_piece"
+
+################
+
diff --git a/scripts/customize/fred/scripts/jobby/uva_strider.sh b/scripts/customize/fred/scripts/jobby/uva_strider.sh
index 3cfc4fce..00fe88ee 100644
--- a/scripts/customize/fred/scripts/jobby/uva_strider.sh
+++ b/scripts/customize/fred/scripts/jobby/uva_strider.sh
@@ -109,6 +109,3 @@ instigate_remote_calls "$init_op" "$remote_op" "$cleanup_op" "$domain" "$hostlis
 
 ################
 
-popd
-
-
-- 
2.34.1