runtime: Document args[0] and the no-usable-args fallback

wking · wking · commit 64b170ce1faa · 2015-08-26T13:54:09.000-07:00
Leaning on Go's docs [1]: > Args holds command line arguments, including the command as > Args[0]. If the Args field is empty or nil, Run uses {Path}. for the fallback wording. This restores the ability to explicitly set args[0] independent of the path, which was requested in #34 [2] and ack-ed by Micheal [3] and Mrunal [4], but didn't match the examples that landed with #34. [1]: http://golang.org/pkg/os/exec/#Cmd [2]: #34 (comment) [3]: #34 (comment) [4]: #34 (comment) Signed-off-by: W. Trevor King <wking@tremily.us>
diff --git a/runtime.md b/runtime.md
@@ -40,7 +40,7 @@ If a hook returns a non-zero exit code, then an error is logged and the remainin
         "prestart": [
             {
                 "path": "/usr/bin/fix-mounts",
-                "args": ["arg1", "arg2"],
+                "args": ["fix-mounts", "arg1", "arg2"],
                 "env":  [ "key1=value1"]
             },
             {
@@ -50,10 +50,14 @@ If a hook returns a non-zero exit code, then an error is logged and the remainin
         "poststop": [
             {
                 "path": "/usr/sbin/cleanup.sh",
-                "args": ["-f"]
+                "args": ["cleanup.sh", "-f"]
             }
         ]
     }
 ```
 
-`path` is required for a hook. `args` and `env` are optional.
+`path` is required for a hook.
+`args` and `env` are optional.
+`args` includes the command as `args[0]`.
+If the `args` field is missing, empty, or `null`, the runtime will use `[path]`.
+In the example above, that means that `/usr/bin/setup-network` will be executed with `/usr/bin/setup-network` as `args[0]` and no other arguments.

Original file line number	Diff line number	Diff line change
`@@ -40,7 +40,7 @@ If a hook returns a non-zero exit code, then an error is logged and the remainin`
`40`	`40`	`"prestart": [`
`41`	`41`	`{`
`42`	`42`	`"path": "/usr/bin/fix-mounts",`
`43`		`- "args": ["arg1", "arg2"],`
	`43`	`+ "args": ["fix-mounts", "arg1", "arg2"],`
`44`	`44`	`"env": [ "key1=value1"]`
`45`	`45`	`},`
`46`	`46`	`{`
`@@ -50,10 +50,14 @@ If a hook returns a non-zero exit code, then an error is logged and the remainin`
`50`	`50`	`"poststop": [`
`51`	`51`	`{`
`52`	`52`	`"path": "/usr/sbin/cleanup.sh",`
`53`		`- "args": ["-f"]`
	`53`	`+ "args": ["cleanup.sh", "-f"]`
`54`	`54`	`}`
`55`	`55`	`]`
`56`	`56`	`}`
`57`	`57`	```
`58`	`58`
`59`		-`path` is required for a hook. `args` and `env` are optional.
	`59`	+`path` is required for a hook.
	`60`	+`args` and `env` are optional.
	`61`	+`args` includes the command as `args[0]`.
	`62`	+If the `args` field is missing, empty, or `null`, the runtime will use `[path]`.
	`63`	+In the example above, that means that `/usr/bin/setup-network` will be executed with `/usr/bin/setup-network` as `args[0]` and no other arguments.