config: Require strictly-positive timeout values

If the timeout value was zero, the hook would always error, and there
doesn't seem to be much point to that.  And I'm not sure what negative
timeouts would mean.  By adding this restriction, we do not limit
useful hook entries, and we give the validation code grounds to warn
users attempting to validate configs which are poorly defined or have
useless hook entries.

Removing the pointer is not strictly required, but keeps up with our
anti-pointer zero-value style (style.md) now that Go's zero-value is
clearly invalid.

Signed-off-by: W. Trevor King <[email protected]>

Author: wking

config.md

@@ -357,6 +357,7 @@ Hooks allow for the configuration of custom actions related to the [lifecycle](r
     * **`args`** (array of strings, OPTIONAL) with the same semantics as [IEEE Std 1003.1-2001 `execv`'s *argv*][ieee-1003.1-2001-xsh-exec].
     * **`env`** (array of strings, OPTIONAL) with the same semantics as [IEEE Std 1003.1-2001's `environ`][ieee-1003.1-2001-xbd-c8.1].
     * **`timeout`** (int, OPTIONAL) is the number of seconds before aborting the hook.
+      If set, `timeout` MUST be greater than zero.
   * **`poststart`** (array of objects, OPTIONAL) is an array of [post-start hooks](#poststart).
     Entries in the array have the same schema as pre-start entries.
   * **`poststop`** (array of objects, OPTIONAL) is an array of [post-stop hooks](#poststop).

schema/defs.json

@@ -91,7 +91,8 @@
                     "$ref": "#/definitions/Env"
                 },
                 "timeout": {
-                    "type": "integer"
+                    "type": "integer",
+                    "minimum": 1
                 }
             },
             "required": [

specs-go/config.go

@@ -126,7 +126,7 @@ type Hook struct {
 	Path    string   `json:"path"`
 	Args    []string `json:"args,omitempty"`
 	Env     []string `json:"env,omitempty"`
-	Timeout *int     `json:"timeout,omitempty"`
+	Timeout int      `json:"timeout,omitempty"`
 }
 
 // Hooks for container setup and teardown