Before this patch, output for invalid top-level and sub-commands differed.
For top-level commands, the CLI would print an error-message and a suggestion
to use `--help`. For missing *subcommands*, we would hit a different code-path,
and different output, which includes full "usage" / "help" output.
While it is a common convention to show usage output, and may have been
a nice gesture when docker was still young and only had a few commands
and options ("you did something wrong; here's an overview of what you
can use"), that's no longer the case, and many commands have a _very_
long output.
The result of this is that the error message, which is the relevant
information in this case - "You mis-typed something" - is lost in the
output, and hard to find (sometimes even requiring scrolling back).
The output is also confusing, because it _looks_ like something ran
successfully (most of the output is not about the error!).
Even further; the suggested resolution (try `--help` to see the correct
options) is rather redundant, because running teh command with `--help`
produces _exactly_ the same output as was just showh, baring the error
message. As a fun fact, due to the usage output being printed, the
output even contains not one, but _two_ "call to actions";
- `See 'docker volume --help'.` (under the erro message)
- `Run 'docker volume COMMAND --help' for more information on a command.`
(under the usage output)
In short; the output is too verbose, confusing, and doesn't provide
a good UX. Let's reduce the output produced so that the focus is on the
important information.
This patch:
- Changes the usage to the short-usage.
- Changes the error-message to mention the _full_ command instead of only
the command after `docker` (so `docker no-such-command` instead of
`no-such-command`).
- Prefixes the error message with the binary / root-command name
(usually `docker:`); this is something we can still decide on, but
it's a pattern we already use in some places. The motivation for this
is that `docker` commands can often produce output that's a combination
of output from the CLI itself, output from the daemon, and even output
from the container. The `docker:` prefix helps to distinguish where
the message originated from (the `docker` CLI in this case).
- Adds an empty line between the error-message and the "call to action"
(`Run 'docker volume --help'...` in the example below). This helps
separating the error message ("unkown flag") from the call-to-action.
Before this patch:
Unknown top-level command:
docker nosuchcommand foo
docker: 'nosuchcommand' is not a docker command.
See 'docker --help'
Unknown sub-command:
docker volume nosuchcommand foo
Usage: docker volume COMMAND
Manage volumes
Commands:
create Create a volume
inspect Display detailed information on one or more volumes
ls List volumes
prune Remove unused local volumes
rm Remove one or more volumes
update Update a volume (cluster volumes only)
Run 'docker volume COMMAND --help' for more information on a command.
After this patch:
Unknown top-level command:
docker nosuchcommand foo
docker: unknown command: docker nosuchcommand
Run 'docker --help' for more information
Unknown sub-command:
docker volume nosuchcommand foo
docker: unknown command: 'docker volume nosuchcommand'
Usage: docker volume COMMAND
Run 'docker volume --help' for more information
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
All output of the usage / --help output uses spaces, and having a tab
in the output can be somewhat cumbersome (e.g. our YAML docs generator
doesn't like them, and copy/pasing the output in iTerm produces a warning).
This patch changes the output to use two spaces instead.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
I regressed this in d4ced2ef77 ("allow plugins to have argument which match a
top-level flag.") by unconditionally overwriting any `PersistentRunE` that the
user may have supplied.
We need to ensure two things:
1. That the user can use `PersistentRunE` (or `PersistentRun`) for their own
purposes.
2. That our initialisation always runs, even if the user has used
`PersistentRun*`, since that will shadow the root.
To do this add a `PersistentRunE` to the helloworld plugin which logs (covers 1
above) and then use it when calling the `apiversion` subcommand (which covers 2
since that uses the client)
Signed-off-by: Ian Campbell <ijc@docker.com>
These won't pass right now due to https://github.com/docker/cli/issues/1699
("Plugins can't re-use the same flags as cli global flags") and the change in
935d47bbe9 ("Ignore unknown arguments on the top-level command."), but the
intention is to fix them now.
Signed-off-by: Ian Campbell <ijc@docker.com>
This allows passing argument to plugins, otherwise they are caught by the parse
loop, since cobra does not know about each plugin at this stage (to avoid
having to always scan for all plugins) this means that e.g. `docker plugin
--foo` would accumulate `plugin` as an arg to the `docker` command, then choke
on the unknown `--foo`.
This allows unknown global args only, unknown arguments on subcommands (e.g.
`docker ps --foo`) are still correctly caught.
Add an e2e test covering this case.
Signed-off-by: Ian Campbell <ijc@docker.com>
Previously a plugin which used these hooks would overwrite the top-level plugin
command's use of this hook, resulting in the dockerCli object not being fully
initialised.
Provide a function which plugins can use to chain to the required behaviour.
This required some fairly ugly arrangements to preserve state (which was
previously in-scope in `newPluginCOmmand`) to be used by the new function.
Signed-off-by: Ian Campbell <ijc@docker.com>
To help with this add a bad plugin which produces invalid metadata and arrange
for it to be built in the e2e container.
Signed-off-by: Ian Campbell <ijc@docker.com>
Sebastiaan van Stijn
Ian Campbell
Corey Quon