Delve Code Analysis Note (4)--Build command tree

This is a creation in Article, where the information may have evolved or changed.

DelveUsed cobra to construct command tree . Look first root command , namely dlv :

Func New () *cobra.    command {...//Main DLV root command. Rootcommand = &cobra. command{use: "DLV", Short: "Delve are a debugger for the Go programming language.", Long:dlvcomma Ndlongdesc,} rootcommand.persistentflags ().    Stringvarp (&ADDR, "Listen", "L", "localhost:0", "Debugging Server Listen address.") Rootcommand.persistentflags ().    Boolvarp (&log, "Log", "" ", False," Enable Debugging Server Logging. ") Rootcommand.persistentflags ().    Boolvarp (&headless, "Headless", "" "," false "," Run Debug server only, in Headless mode. ") Rootcommand.persistentflags (). Boolvarp (&acceptmulti, "accept-multiclient", "" "," false, "allows a headless server to accept multiple client connection S. Note the server API is not reentrant and clients'll has to coordinate ") rootcommand.persistentflags (). Intvar (&apiversion, "api-version", 1, "selects API version when headless") rootcommand.persistentflags (). Stringvar (&initfile, "Init", "", "Init file, executed by the terminal client.") Rootcommand.persistentflags ().    Stringvar (&buildflags, "Build-flags", Buildflagsdefault, "build flags, to is passed to the compiler.") ......}

Because dlv command there is no implementation run function, running dlv the command alone will only print cobra the default output that helps generate:

# dlvDelve is a source level debugger for Go programs.......Usage:  dlv [command]Available Commands:  version     Prints version.  ......Flags:      --accept-multiclient[=false]: Allows a headless server to accept multiple client connections. Note that the server API is not reentrant and clients will have to coordinate    ......

In turn Long description , Usage and Available Commands so on.

Again trace subcommand , for example, see How to subcommand add to the root command inside:

......// 'trace' subcommand.traceCommand := &cobra.Command{    Use:   "trace [package] regexp",    Short: "Compile and begin tracing program.",    Long:  "Trace program execution. Will set a tracepoint on every function matching the provided regular expression and output information when tracepoint is hit.",    Run:   traceCmd,}traceCommand.Flags().IntVarP(&traceAttachPid, "pid", "p", 0, "Pid to attach to.")traceCommand.Flags().IntVarP(&traceStackDepth, "stack", "s", 0, "Show stack trace with given depth.")RootCommand.AddCommand(traceCommand)......

CobraAvailable in two types flags :
A) Persistent Flags : valid for both the current command and its sub-commands;
b) Local Flags : Valid only for the current command.