cli/command/container: add completion for --cap-add, --cap-drop

With this patch:

    docker run --cap-add <TAB>
    ALL                     CAP_KILL                CAP_SETUID
    CAP_AUDIT_CONTROL       CAP_LEASE               CAP_SYSLOG
    CAP_AUDIT_READ          CAP_LINUX_IMMUTABLE     CAP_SYS_ADMIN
    CAP_AUDIT_WRITE         CAP_MAC_ADMIN           CAP_SYS_BOOT
    CAP_BLOCK_SUSPEND       CAP_MAC_OVERRIDE        CAP_SYS_CHROOT
    CAP_BPF                 CAP_MKNOD               CAP_SYS_MODULE
    CAP_CHECKPOINT_RESTORE  CAP_NET_ADMIN           CAP_SYS_NICE
    CAP_CHOWN               CAP_NET_BIND_SERVICE    CAP_SYS_PACCT
    CAP_DAC_OVERRIDE        CAP_NET_BROADCAST       CAP_SYS_PTRACE
    CAP_DAC_READ_SEARCH     CAP_NET_RAW             CAP_SYS_RAWIO
    CAP_FOWNER              CAP_PERFMON             CAP_SYS_RESOURCE
    CAP_FSETID              CAP_SETFCAP             CAP_SYS_TIME
    CAP_IPC_LOCK            CAP_SETGID              CAP_SYS_TTY_CONFIG
    CAP_IPC_OWNER           CAP_SETPCAP             CAP_WAKE_ALARM

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/command/container/completion.go

@@ -0,0 +1,69 @@
+package container
+
+import (
+	"github.com/docker/cli/cli/command/completion"
+	"github.com/spf13/cobra"
+)
+
+// allLinuxCapabilities is a list of all known Linux capabilities.
+//
+// This list was based on the containerd pkg/cap package;
+// https://github.com/containerd/containerd/blob/v1.7.19/pkg/cap/cap_linux.go#L133-L181
+//
+// TODO(thaJeztah): add descriptions, and enable descriptions for our completion scripts (cobra.CompletionOptions.DisableDescriptions is currently set to "true")
+var allLinuxCapabilities = []string{
+	"ALL", // magic value for "all capabilities"
+
+	// caps35 is the caps of kernel 3.5 (37 entries)
+	"CAP_CHOWN",            // 2.2
+	"CAP_DAC_OVERRIDE",     // 2.2
+	"CAP_DAC_READ_SEARCH",  // 2.2
+	"CAP_FOWNER",           // 2.2
+	"CAP_FSETID",           // 2.2
+	"CAP_KILL",             // 2.2
+	"CAP_SETGID",           // 2.2
+	"CAP_SETUID",           // 2.2
+	"CAP_SETPCAP",          // 2.2
+	"CAP_LINUX_IMMUTABLE",  // 2.2
+	"CAP_NET_BIND_SERVICE", // 2.2
+	"CAP_NET_BROADCAST",    // 2.2
+	"CAP_NET_ADMIN",        // 2.2
+	"CAP_NET_RAW",          // 2.2
+	"CAP_IPC_LOCK",         // 2.2
+	"CAP_IPC_OWNER",        // 2.2
+	"CAP_SYS_MODULE",       // 2.2
+	"CAP_SYS_RAWIO",        // 2.2
+	"CAP_SYS_CHROOT",       // 2.2
+	"CAP_SYS_PTRACE",       // 2.2
+	"CAP_SYS_PACCT",        // 2.2
+	"CAP_SYS_ADMIN",        // 2.2
+	"CAP_SYS_BOOT",         // 2.2
+	"CAP_SYS_NICE",         // 2.2
+	"CAP_SYS_RESOURCE",     // 2.2
+	"CAP_SYS_TIME",         // 2.2
+	"CAP_SYS_TTY_CONFIG",   // 2.2
+	"CAP_MKNOD",            // 2.4
+	"CAP_LEASE",            // 2.4
+	"CAP_AUDIT_WRITE",      // 2.6.11
+	"CAP_AUDIT_CONTROL",    // 2.6.11
+	"CAP_SETFCAP",          // 2.6.24
+	"CAP_MAC_OVERRIDE",     // 2.6.25
+	"CAP_MAC_ADMIN",        // 2.6.25
+	"CAP_SYSLOG",           // 2.6.37
+	"CAP_WAKE_ALARM",       // 3.0
+	"CAP_BLOCK_SUSPEND",    // 3.5
+
+	// caps316 is the caps of kernel 3.16 (38 entries)
+	"CAP_AUDIT_READ",
+
+	// caps58 is the caps of kernel 5.8 (40 entries)
+	"CAP_PERFMON",
+	"CAP_BPF",
+
+	// caps59 is the caps of kernel 5.9 (41 entries)
+	"CAP_CHECKPOINT_RESTORE",
+}
+
+func completeLinuxCapabilityNames(cmd *cobra.Command, args []string, toComplete string) (names []string, _ cobra.ShellCompDirective) {
+	return completion.FromList(allLinuxCapabilities...)(cmd, args, toComplete)
+}

cli/command/container/create.go

@@ -78,6 +78,8 @@ func NewCreateCommand(dockerCli command.Cli) *cobra.Command {
 	command.AddTrustVerificationFlags(flags, &options.untrusted, dockerCli.ContentTrustEnabled())
 	copts = addFlags(flags)
 
+	_ = cmd.RegisterFlagCompletionFunc("cap-add", completeLinuxCapabilityNames)
+	_ = cmd.RegisterFlagCompletionFunc("cap-drop", completeLinuxCapabilityNames)
 	_ = cmd.RegisterFlagCompletionFunc("env", completion.EnvVarNames)
 	_ = cmd.RegisterFlagCompletionFunc("env-file", completion.FileNames)
 	_ = cmd.RegisterFlagCompletionFunc("network", completion.NetworkNames(dockerCli))

cli/command/container/run.go

@@ -69,6 +69,8 @@ func NewRunCommand(dockerCli command.Cli) *cobra.Command {
 	command.AddTrustVerificationFlags(flags, &options.untrusted, dockerCli.ContentTrustEnabled())
 	copts = addFlags(flags)
 
+	_ = cmd.RegisterFlagCompletionFunc("cap-add", completeLinuxCapabilityNames)
+	_ = cmd.RegisterFlagCompletionFunc("cap-drop", completeLinuxCapabilityNames)
 	_ = cmd.RegisterFlagCompletionFunc("env", completion.EnvVarNames)
 	_ = cmd.RegisterFlagCompletionFunc("env-file", completion.FileNames)
 	_ = cmd.RegisterFlagCompletionFunc("network", completion.NetworkNames(dockerCli))