Make PATH and dependency fixes

newsfragments/869.bugfix

@@ -0,0 +1 @@
+Telepresence now reports an error if your command cannot be launched.

telepresence/outbound/local.py

@@ -119,7 +119,10 @@ def launch_vpn(
     """
     connect_sshuttle(runner, remote_info, also_proxy, ssh)
     env = get_local_env(runner, env_overrides, False)
-    process = Popen(command, env=env)
+    try:
+        process = Popen(command, env=env)
+    except OSError as exc:
+        raise runner.fail("Failed to launch your command: {}".format(exc))
     runner.add_cleanup(
         "Terminate local process", terminate_local_process, runner, process
     )

telepresence/outbound/setup.py

@@ -18,7 +18,14 @@
 from .local import launch_inject, launch_vpn
 
 
+def check_local_command(runner: Runner, command: str) -> None:
+    if runner.depend([command]):
+        raise runner.fail("{}: command not found".format(command))
+
+
 def setup_inject(runner: Runner, args):
+    command = ["torsocks"] + (args.run or ["bash", "--norc"])
+    check_local_command(runner, command[1])
     runner.require(["torsocks"], "Please install torsocks (v2.1 or later)")
     if runner.chatty:
         runner.show(
@@ -28,7 +35,6 @@ def setup_inject(runner: Runner, args):
             "method limitations see "
             "https://telepresence.io/reference/methods.html"
         )
-    command = ["torsocks"] + (args.run or ["bash", "--norc"])
 
     def launch(
         runner_, _remote_info, env, socks_port, _ssh, _mount_dir, _pod_info
@@ -39,6 +45,8 @@ def launch(
 
 
 def setup_vpn(runner: Runner, args):
+    command = args.run or ["bash", "--norc"]
+    check_local_command(runner, command[0])
     runner.require(["sshuttle-telepresence"],
                    "Part of the Telepresence package. Try reinstalling.")
     if runner.platform == "linux":
@@ -57,7 +65,6 @@ def setup_vpn(runner: Runner, args):
             "a full list of method limitations see "
             "https://telepresence.io/reference/methods.html"
         )
-    command = args.run or ["bash", "--norc"]
 
     def launch(
         runner_, remote_info, env, _socks_port, ssh, _mount_dir, _pod_info

telepresence/runner/runner.py

@@ -202,6 +202,7 @@ def require_sudo(self) -> None:
         if self.sudo_held:
             return
 
+        self.require(["sudo"], "Some operations require elevated privileges")
         try:
             # See whether we can grab privileges without a password
             self.check_call(["sudo", "-n", "echo", "-n"])
@@ -223,7 +224,14 @@ def depend(self, commands: typing.Iterable[str]) -> typing.List[str]:
         """
         Find unavailable commands from a set of dependencies
         """
-        return [command for command in commands if which(command) is None]
+        missing = []
+        for command in commands:
+            path = which(command)
+            if path:
+                self.write("Found {} -> {}".format(command, path))
+            else:
+                missing.append(command)
+        return missing
 
     def require(self, commands: typing.Iterable[str], message: str) -> None:
         """