[28.x backport] cli/flags: add "hostVar" to handle --host / -H as a single string #6289
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The ClientOptions struct and related flags were inherited from the Moby repository, where originally the CLI and Daemon used the same implementation and had a "Common" options struct. When the CLI moved to a separate repository, those structs were duplicated, but some daemon-specific logic remained. For example, the daemon can be configured to listen on multiple ports and sockets ([moby@dede158]), but the CLI [can only connect to a single host][1]. The daemon config also had to account for flags conflicting with `daemon.json`, and use special flag-vars for this ([moby@677a6b3]). Unfortunately, the `ClientConfig` struct became part of the public API and is used as argument in various places, but we can remove the use of the special flag var. This patch replaces the use of `NewNamedListOptsRef` for a regular `StringArray`. Unfortunately this changes the flag's type description from `list` to `stringArray`, but we can look at changing that separately. [moby@dede158]: moby/moby@dede158 [1]: https://github.com/moby/moby/blob/0af135e9065562e14a77439e13a29b4f1eb627a0/docker/docker.go#L191-L193 [moby@677a6b3]: moby/moby@677a6b3 Signed-off-by: Sebastiaan van Stijn <[email protected]> (cherry picked from commit 5ee2906) Signed-off-by: Sebastiaan van Stijn <[email protected]>
hostVar is used for the '--host' / '-H' flag to set [ClientOptions.Hosts]. The [ClientOptions.Hosts] field is a slice because it was originally shared with the daemon config. However, the CLI only allows for a single host to be specified. hostVar presents itself as a "string", but stores the value in a string slice. It produces an error when trying to set multiple values, matching the check in [getServerHost]. [getServerHost]: https://github.com/docker/cli/blob/7eab668982645def1cd46fe1b60894cba6fd17a4/cli/command/cli.go#L542-L551 Signed-off-by: Sebastiaan van Stijn <[email protected]> (cherry picked from commit f14eeeb) Signed-off-by: Sebastiaan van Stijn <[email protected]>
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Benehiko
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Aug 18, 2025
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cli/flags: use a regular StringArray for the
--host/-HflagThe ClientOptions struct and related flags were inherited from the Moby repository, where originally the CLI and Daemon used the same implementation and had a "Common" options struct. When the CLI moved to a separate repository, those structs were duplicated, but some daemon-specific logic remained. For example, the daemon can be configured to listen on multiple ports and sockets (moby@dede158), but the CLI can only connect to a single host. The daemon config also had to account for flags conflicting with
daemon.json, and use special flag-vars for this (moby@677a6b3).Unfortunately, the
ClientConfigstruct became part of the public API and is used as argument in various places, but we can remove the use of the special flag var. This patch replaces the use ofNewNamedListOptsReffor a regularStringArray.Unfortunately this changes the flag's type description from
listtostringArray, but we can look at changing that separately.cli/flags: add "hostVar" to handle --host / -H as a single string
hostVar is used for the '--host' / '-H' flag to set [ClientOptions.Hosts].
The [ClientOptions.Hosts] field is a slice because it was originally shared
with the daemon config. However, the CLI only allows for a single host to
be specified.
hostVar presents itself as a "string", but stores the value in a string
slice. It produces an error when trying to set multiple values, matching
the check in getServerHost.
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