Adjust exit codes

bin/cget.sh

@@ -25,7 +25,7 @@ display_help () {
 	This script retrieves and caches HTTP resources on disk. 
 	A previously cached resource is retrieved via HTTP Conditional 
 	GET [RFC 7232]. If the web server responds with HTTP 200 OK,
-	the resource is cached and written to stdout. If the web 
+	the new resource is cached and written to stdout. If the web 
 	server responds with 304 Not Modified, the cached resource 
 	is output instead.
 	
@@ -49,15 +49,17 @@ display_help () {
 
 	Option -h is mutually exclusive of all other options.
 	
-	The default behavior of the script may be modified by using 
+	The default behavior of the script is modified by using 
 	option -F or -C, which are mutually exclusive. Force Output 
 	Mode (option -F) forces the return of a fresh resource. The 
 	resource is output on stdout if and only if the server 
-	responds with 200. If the response is 304, an error is thrown.
+	responds with 200. If the response is 304, the script silently
+	fails with exit code 1.
 	 
 	Cache Only Mode (option -C) bypasses the GET request altogether 
 	and goes directly to cache. If the resource resides in cache, 
-	it is output on stdout, otherwise an error is thrown.
+	it is output on stdout, otherwise the script silently fails
+	with exit code 1.
 	
 	LIBRARY
 	
@@ -152,8 +154,8 @@ if [ ! -d "$CACHE_DIR" ]; then
 	/bin/mkdir "$CACHE_DIR"
 	exit_code=$?
 	if [ $exit_code -ne 0 ]; then
-		echo "ERROR: $script_name failed to create dir: $CACHE_DIR" >&2
-		exit $exit_code
+		echo "ERROR: $script_name failed to create dir $CACHE_DIR (exit code: $exit_code)" >&2
+		exit 2
 	fi
 fi
 $verbose_mode && printf "$script_name using cache directory: %s\n" "$CACHE_DIR"
@@ -180,8 +182,8 @@ for lib_filename in $LIB_FILENAMES; do
 	source "$lib_file" >&2
 	exit_code=$?
 	if [ $exit_code -ne 0 ]; then
-		echo "ERROR: $script_name failed to source script $lib_file" >&2
-		exit $exit_code
+		echo "ERROR: $script_name failed to source script $lib_file (exit code: $exit_code)" >&2
+		exit 2
 	fi
 done
 
@@ -203,10 +205,10 @@ else
 fi
 if [ ! -d "$TMP_DIR" ]; then
 	/bin/mkdir "$TMP_DIR"
-	exit_status=$?
-	if [ $exit_status -ne 0 ]; then
-		echo "ERROR: $script_name failed to create dir: $TMP_DIR" >&2
-		exit $exit_status
+	exit_code=$?
+	if [ $exit_code -ne 0 ]; then
+		echo "ERROR: $script_name failed to create dir $TMP_DIR (exit code: $exit_code)" >&2
+		exit 2
 	fi
 fi
 
@@ -217,14 +219,20 @@ tmp_file="${TMP_DIR}/http_resource_$$.xml"
 # Main processing
 #######################################################################
 
-# get the resource
+# The conditional_get function is defined and documented 
+# in library file http_tools.sh.
+#
+$verbose_mode && printf "$script_name requesting resource: %s\n" "$location"
 conditional_get $local_opts -d "$CACHE_DIR" -t "$TMP_DIR" "$location" > "$tmp_file"
 exit_code=$?
 if [ $exit_code -ne 0 ]; then
-	echo "ERROR: $script_name failed to get resource: $location" >&2
-	printf "See output log: %s\n" "$TMP_DIR/$conditional_get_log" >&2
+	if [ $exit_code -gt 1 ]; then
+		echo "ERROR: $script_name failed to get resource: $location" >&2
+		printf "See output log: %s\n" "$TMP_DIR/$conditional_get_log" >&2
+	fi
 	exit $exit_code
 fi
+$verbose_mode && printf "$script_name successfully obtained resource: %s\n" "$tmp_file"
 
 /bin/cat "$tmp_file"
 exit 0