[Libguestfs] [PATCH] v2v: -o openstack: Check openstack binary exists before running it.

Improves the error message when openstack is not installed: $ virt-v2v -i disk fedora-28.img -o openstack virt-v2v: error: no binary called ‘openstack’ was found on the $PATH. We use this program to communicate with OpenStack so it must be installed to use this output mode. --- v2v/output_openstack.ml | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/v2v/output_openstack.ml b/v2v/output_openstack.ml index b5bbc9195..238ec99a9 100644 --- a/v2v/output_openstack.ml +++ b/v2v/output_openstack.ml @@ -28,6 +28,9 @@ open Common_gettext.Gettext open Types open Utils +(* Name of the openstack CLI program (on $PATH). *) +let openstack_binary = "openstack" + (* Timeout waiting for new Cinder volumes to move to "available" state. * We assume this could be quite a long time on backends which want * to preallocate the storage. @@ -172,13 +175,20 @@ class output_openstack output_conn output_password output_storage object_get_string "uuid" json ) in + let error_unless_openstack_command_exists () = + try ignore (which openstack_binary) + with Executable_not_found _ -> + error (f_"no binary called ‘%s’ was found on the $PATH. We use this program to communicate with OpenStack so it must be installed to use this output mode.") + openstack_binary + in + (* We use this convenient wrapper around [Tools_utils.run_command] * for two reasons: (1) Because we want to run openstack with * extra_args. (2) OpenStack commands are noisy so we want to * direct stdout to /dev/null unless we're in verbose mode. *) let run_openstack_command args = - let cmd = [ "openstack" ] @ extra_args @ args in + let cmd = [ openstack_binary ] @ extra_args @ args in let stdout_fd = if verbose () then None else Some (openfile "/dev/null" [O_WRONLY] 0) in @@ -191,7 +201,7 @@ class output_openstack output_conn output_password output_storage * '-f json' to the args yourself. *) let run_openstack_command_capture_json args = - let cmd = [ "openstack" ] @ extra_args @ args in + let cmd = [ openstack_binary ] @ extra_args @ args in let json, chan = Filename.open_temp_file "v2vopenstack" ".json" in unlink_on_exit json; @@ -366,6 +376,9 @@ object inherit output method precheck () = + (* Check the openstack command exists. *) + error_unless_openstack_command_exists (); + (* Run the openstack command simply to check we can connect * with the provided authentication parameters/environment * variables. Issuing a token should have only a tiny -- 2.19.0.rc0