Gem support (#299)

Co-authored-by: Tim Coutinho <tmcoutinho42@gmail.com>

shallow_backup/backup.py

@@ -138,12 +138,6 @@ def run_cmd_if_no_dry_run(command, dest, dry_run) -> int:
 	if not dry_run:
 		overwrite_dir_prompt_if_needed(backup_path, skip)
 
-	# ruby
-	print_pkg_mgr_backup("gem")
-	command = "gem list"
-	dest = f"{backup_path}/gem_list.txt"
-	run_cmd_if_no_dry_run(command, dest, dry_run)
-
 	# brew
 	print_pkg_mgr_backup("brew")
 	command = f"brew bundle dump --file {backup_path}/brew_list.txt"
@@ -152,6 +146,12 @@ def run_cmd_if_no_dry_run(command, dest, dry_run) -> int:
 		if not run_cmd(command):
 			print_yellow("brew package manager not found.")
 
+	# ruby
+	print_pkg_mgr_backup("gem")
+	command = r"gem list | tail -n+1 | sed -E 's/\((default: )?(.*)\)/--version \2/'"
+	dest = f"{backup_path}/gem_list.txt"
+	run_cmd_if_no_dry_run(command, dest, dry_run)
+
 	# cargo
 	print_pkg_mgr_backup("cargo")
 	command = r"cargo install --list | grep '^\w.*:$' | sed -E 's/ v(.*):$/ --version \1/'"

shallow_backup/reinstall.py

@@ -164,7 +164,9 @@ def run_cmd_if_no_dry_run(command, dry_run) -> int:
 		elif pm == "macports":
 			print_red_bold("WARNING: Macports reinstallation is not supported.")
 		elif pm == "gem":
-			print_red_bold("WARNING: Gem reinstallation is not supported.")
+			print_pkg_mgr_reinstall(pm)
+			cmd = f"cat {packages_path}/gem_list.txt | xargs -L 1 gem install"
+			run_cmd_if_no_dry_run(cmd, dry_run)
 		elif pm == "cargo":
 			print_pkg_mgr_reinstall(pm)
 			cmd = f"cat {packages_path}/cargo_list.txt | xargs -L 1 cargo install"

shallow_backup/utils.py

@@ -1,39 +1,41 @@
 import os
 import subprocess as sp
+from shlex import split
 from shutil import rmtree, copytree
+from typing import List, Union
 from .printing import *
 
 
-def run_cmd(command: str):
+def run_cmd(command: Union[str, List]):
 	"""
 	Wrapper on subprocess.run to handle shell commands as either a list of args
 	or a single string.
 	"""
+	if not isinstance(command, list):
+		command = split(command)
+	output = None
 	try:
-		if not isinstance(command, list):
-			process = sp.run(command.split(), stdout=sp.PIPE, stderr=sp.DEVNULL)
-			return process
-		else:
-			process = sp.run(command, stdout=sp.PIPE, stderr=sp.DEVNULL)
-			return process
+		while "|" in command:
+			index = command.index("|")
+			first_command, command = command[:index], command[index + 1:]
+			output = sp.Popen(first_command, stdin=output.stdout if output else None, stdout=sp.PIPE, stderr=sp.DEVNULL)
+		return sp.run(command, stdout=sp.PIPE, stdin=output.stdout if output else None, stderr=sp.DEVNULL)
 	except FileNotFoundError:  # If package manager is missing
 		return None
 
 
-def run_cmd_write_stdout(command, filepath) -> int:
+def run_cmd_write_stdout(command: str, filepath: str) -> int:
 	"""
 	Runs a command and then writes its stdout to a file.
-	Returns the returncode if the return value is not 0.
+	Returns 0 on success, and -1 on failure.
 	:param: command str representing command to run
 	:param: filepath str file to write command's stdout to
 	"""
 	process = run_cmd(command)
 	if process and process.returncode == 0:
 		with open(filepath, "w+") as f:
 			f.write(process.stdout.decode('utf-8'))
-	elif process:
-		print_path_red("An error occurred while running: $", command)
-		return process.returncode
+		return 0
 	else:
 		print_path_red("An error occurred while running: $", command)
 		return -1