197 lines
4.3 KiB
Markdown
197 lines
4.3 KiB
Markdown
Migration Guide: v1 to v2
|
|
===
|
|
|
|
|
|
v2 has a number of breaking changes but converting is relatively
|
|
straightforward: make the changes documented below then resolve any
|
|
compiler errors. We hope this will be sufficient for most typical
|
|
users.
|
|
|
|
If you find any issues not covered by this document, please post a
|
|
comment on [Issue 921](https://github.com/urfave/cli/issues/921) or
|
|
consider sending a PR to help improve this guide.
|
|
|
|
<!-- toc -->
|
|
|
|
* [Flags before args](#flags-before-args)
|
|
* [Import string changed](#import-string-changed)
|
|
* [Flag aliases are done differently.](#flag-aliases-are-done-differently)
|
|
* [EnvVar is now a list (EnvVars)](#envvar-is-now-a-list-envvars)
|
|
* [Commands are now lists of pointers](#commands-are-now-lists-of-pointers)
|
|
* [Lists of commands should be pointers](#lists-of-commands-should-be-pointers)
|
|
* [cli.Flag changed](#cliflag-changed)
|
|
* [Appending Commands](#appending-commands)
|
|
* [Actions returns errors](#actions-returns-errors)
|
|
* [Everything else](#everything-else)
|
|
* [Full API Example](#full-api-example)
|
|
|
|
<!-- tocstop -->
|
|
|
|
# Flags before args
|
|
|
|
In v2 flags must come before args. This is more POSIX-compliant. You
|
|
may need to update scripts, user documentation, etc.
|
|
|
|
This will work:
|
|
|
|
```
|
|
cli hello --shout rick
|
|
```
|
|
|
|
This will not:
|
|
|
|
```
|
|
cli hello rick --shout
|
|
```
|
|
|
|
# Import string changed
|
|
|
|
* OLD: `import "github.com/urfave/cli"`
|
|
* NEW: `import "github.com/urfave/cli/v2"`
|
|
|
|
Check each file for this and make the change.
|
|
|
|
Shell command to find them all: `fgrep -rl github.com/urfave/cli *`
|
|
|
|
# Flag aliases are done differently.
|
|
|
|
Change `Name: "foo, f"` to `Name: "foo", Aliases: []string{"f"}`
|
|
|
|
* OLD:
|
|
```go
|
|
cli.StringFlag{
|
|
Name: "config, cfg"
|
|
}
|
|
```
|
|
|
|
* NEW:
|
|
```go
|
|
cli.StringFlag{
|
|
Name: "config",
|
|
Aliases: []string{"cfg"},
|
|
}
|
|
```
|
|
|
|
Sadly v2 doesn't warn you if a comma is in the name.
|
|
(https://github.com/urfave/cli/issues/1103)
|
|
|
|
# EnvVar is now a list (EnvVars)
|
|
|
|
Change `EnvVar: "XXXXX"` to `EnvVars: []string{"XXXXX"}` (plural).
|
|
|
|
* OLD:
|
|
```go
|
|
cli.StringFlag{
|
|
EnvVar: "APP_LANG"
|
|
}
|
|
```
|
|
|
|
* NEW:
|
|
```go
|
|
cli.StringFlag{
|
|
EnvVars: []string{"APP_LANG"}
|
|
}
|
|
```
|
|
|
|
# Actions returns errors
|
|
|
|
A command's `Action:` now returns an `error`.
|
|
|
|
* OLD: `Action: func(c *cli.Context) {`
|
|
* NEW: `Action: func(c *cli.Context) error {`
|
|
|
|
Compiler messages you might see:
|
|
|
|
```
|
|
cannot use func literal (type func(*cli.Context)) as type cli.ActionFunc in field value
|
|
```
|
|
|
|
# cli.Flag changed
|
|
|
|
`cli.Flag` is now a list of pointers.
|
|
|
|
What this means to you:
|
|
|
|
If you make a list of flags, add a `&` in front of each
|
|
item. cli.BoolFlag, cli.StringFlag, etc.
|
|
|
|
* OLD:
|
|
```go
|
|
app.Flags = []cli.Flag{
|
|
cli.BoolFlag{
|
|
```
|
|
|
|
* NEW:
|
|
```go
|
|
app.Flags = []cli.Flag{
|
|
&cli.BoolFlag{
|
|
```
|
|
|
|
Compiler messages you might see:
|
|
|
|
```
|
|
cli.StringFlag does not implement cli.Flag (Apply method has pointer receiver)
|
|
```
|
|
|
|
# Commands are now lists of pointers
|
|
|
|
Occurrences of `[]Command` have been changed to `[]*Command`.
|
|
|
|
What this means to you:
|
|
|
|
Look for `[]cli.Command{}` and change it to `[]*cli.Command{}`
|
|
|
|
Example:
|
|
|
|
* OLD: `var commands = []cli.Command{}`
|
|
* NEW: `var commands = []*cli.Command{}`
|
|
|
|
Compiler messages you might see:
|
|
|
|
```
|
|
cannot convert commands (type []cli.Command) to type cli.CommandsByName
|
|
cannot use commands (type []cli.Command) as type []*cli.Command in assignment
|
|
```
|
|
|
|
# Lists of commands should be pointers
|
|
|
|
If you are building up a list of commands, the individual items should
|
|
now be pointers.
|
|
|
|
* OLD: `cli.Command{`
|
|
* NEW: `&cli.Command{`
|
|
|
|
Compiler messages you might see:
|
|
|
|
```
|
|
cannot use cli.Command literal (type cli.Command) as type *cli.Command in argument to
|
|
```
|
|
|
|
# Appending Commands
|
|
|
|
Appending to a list of commands needs to be changed since the list is
|
|
now pointers.
|
|
|
|
* OLD: `commands = append(commands, *c)`
|
|
* NEW: `commands = append(commands, c)`
|
|
|
|
Compiler messages you might see:
|
|
|
|
```
|
|
cannot use c (type *cli.Command) as type cli.Command in append
|
|
```
|
|
|
|
# Everything else
|
|
|
|
Compile the code and work through any errors. Most should
|
|
relate to issues listed above.
|
|
|
|
Once it compiles, test the command. Review the output of `-h` or any
|
|
help messages to verify they match the intended flags and subcommands.
|
|
Then test the program itself.
|
|
|
|
If you find any issues not covered by this document please let us know
|
|
by submitting a comment on
|
|
[Issue 921](https://github.com/urfave/cli/issues/921)
|
|
so that others can benefit.
|