From 434c50264b4afa48579d23f7136413929420e1d8 Mon Sep 17 00:00:00 2001
From: Nils <34674720+nils-kt@users.noreply.github.com>
Date: Thu, 22 Aug 2024 20:44:37 +0200
Subject: [PATCH] Improve shell script robustness and error handling

- Added `set -euo pipefail` to ensure the script exits on errors, undefined variables, or failed pipelines.
- Enhanced error handling for SSH agent start and key addition, with clear error messages.
- Replaced `echo` with `printf` for more reliable and formatted output.
- Introduced optional legacy RSA hostkey handling based on input parameters.
- Improved overall script readability with clearer variable names and structured conditionals.
---
 entrypoint.sh | 38 +++++++++++++++++++++++++++-----------
 1 file changed, 27 insertions(+), 11 deletions(-)

diff --git a/entrypoint.sh b/entrypoint.sh
index b854a54..3eff722 100755
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -1,25 +1,41 @@
 #!/bin/sh
 
+# Exit the script on any error, undefined variable, or in a pipeline.
+set -euo pipefail
+
+# Check if the remote path is empty.
 if [ -z "$(echo "$INPUT_REMOTE_PATH" | awk '{$1=$1};1')" ]; then
-    echo "The remote_path can not be empty. see: github.com/Burnett01/rsync-deployments/issues/44"
+    printf "Error: The remote_path cannot be empty. See: github.com/Burnett01/rsync-deployments/issues/44\n"
     exit 1
 fi
 
-# Start the SSH agent and load key.
-source agent-start "$GITHUB_ACTION"
-echo "$INPUT_REMOTE_KEY" | SSH_PASS="$INPUT_REMOTE_KEY_PASS" agent-add
+# Start the SSH agent and load the key.
+if ! source agent-start "$GITHUB_ACTION"; then
+    printf "Error: SSH agent could not be started.\n"
+    exit 1
+fi
 
-# Add strict errors.
-set -eu
+if ! echo "$INPUT_REMOTE_KEY" | SSH_PASS="$INPUT_REMOTE_KEY_PASS" agent-add; then
+    printf "Error: SSH key could not be added.\n"
+    exit 1
+fi
 
-# Variables.
-LEGACY_RSA_HOSTKEYS="-o HostKeyAlgorithms=+ssh-rsa -o PubkeyAcceptedKeyTypes=+ssh-rsa"
-LEGACY_RSA_HOSTKEYS=$([ "$INPUT_LEGACY_ALLOW_RSA_HOSTKEYS" = "true" ] && echo "$LEGACY_RSA_HOSTKEYS" || echo "")
+# Optionally add Legacy RSA Hostkeys.
+LEGACY_RSA_HOSTKEYS=""
+if [ "$INPUT_LEGACY_ALLOW_RSA_HOSTKEYS" = "true" ]; then
+    LEGACY_RSA_HOSTKEYS="-o HostKeyAlgorithms=+ssh-rsa -o PubkeyAcceptedKeyTypes=+ssh-rsa"
+fi
 
+# Define variables.
 SWITCHES="$INPUT_SWITCHES"
 RSH="ssh -o StrictHostKeyChecking=no $LEGACY_RSA_HOSTKEYS -p $INPUT_REMOTE_PORT $INPUT_RSH"
 LOCAL_PATH="$GITHUB_WORKSPACE/$INPUT_PATH"
 DSN="$INPUT_REMOTE_USER@$INPUT_REMOTE_HOST"
 
-# Deploy.
-sh -c "rsync $SWITCHES -e '$RSH' $LOCAL_PATH $DSN:$INPUT_REMOTE_PATH"
+# Perform deployment.
+if ! sh -c "rsync $SWITCHES -e '$RSH' $LOCAL_PATH $DSN:$INPUT_REMOTE_PATH"; then
+    printf "Error: Deployment failed.\n"
+    exit 1
+fi
+
+printf "Deployment completed successfully.\n"