Reviewers: mp+122016_code.launchpad.net,

Message:
Please take a look.

Description:
environs/config: add support for agent version.

Also adjust documentation for schema.Omit slightly
and add a test.

https://code.launchpad.net/~rogpeppe/juju-core/041-config-agent-version/+merge/122016

(do not edit description out of merge proposal)


Please review this at https://codereview.appspot.com/6499055/

Affected files:
   A [revision details]
   M environs/config/config.go
   M environs/config/config_test.go
   M schema/schema.go
   M schema/schema_test.go


Index: [revision details]
=== added file '[revision details]'
--- [revision details]	2012-01-01 00:00:00 +0000
+++ [revision details]	2012-01-01 00:00:00 +0000
@@ -0,0 +1,2 @@
+Old revision: <email address hidden>
+New revision: <email address hidden>

Index: schema/schema.go
=== modified file 'schema/schema.go'
--- schema/schema.go	2012-07-26 18:01:24 +0000
+++ schema/schema.go	2012-08-30 09:11:09 +0000
@@ -322,8 +322,8 @@
  // and returns with the underlying error.
  //
  // Fields in defaults will be set to the provided value if not present
-// in the coerced map. If the default value is schema.Omit, the field
-// missing field will be ommitted from the coerced map as well.
+// in the coerced map. If the default value is schema.Omit, the
+// missing field will be omitted from the coerced map.
  //
  // The coerced output value has type map[string]interface{}.
  func FieldMap(fields Fields, defaults Defaults) Checker {


Index: schema/schema_test.go
=== modified file 'schema/schema_test.go'
--- schema/schema_test.go	2012-07-26 18:08:04 +0000
+++ schema/schema_test.go	2012-08-30 09:11:09 +0000
@@ -285,6 +285,10 @@
  	out, err :=  
sch.Coerce(map[string]interface{}{"a": "A", "b": "B", "d": "D"}, aPath)
  	c.Assert(err, IsNil)
  	c.Assert(out, DeepEquals,  
map[string]interface{}{"a": "A", "b": "B", "c": "C"})
+
+	out, err = sch.Coerce(map[string]interface{}{"a": "A", "d": "D"}, aPath)
+	c.Assert(err, IsNil)
+	c.Assert(out, DeepEquals, map[string]interface{}{"a": "A", "c": "C"})
  }

  func (s *S) TestFieldMapDefaultInvalid(c *C) {


Index: environs/config/config.go
=== modified file 'environs/config/config.go'
--- environs/config/config.go	2012-08-02 08:29:38 +0000
+++ environs/config/config.go	2012-08-30 09:11:09 +0000
@@ -47,6 +47,13 @@
  		}
  	}

+	// Check that the agent version parses ok if set.
+	if v, ok := c.m["agent-version"].(string); ok {
+		if _, err := version.Parse(v); err != nil {
+			return nil, fmt.Errorf("invalid agent version in environment  
configuration: %q", v)
+		}
+	}
+
  	// Copy unknown attributes onto the type-specific map.
  	for k, v := range attrs {
  		if _, ok := fields[k]; !ok {
@@ -76,6 +83,20 @@
  	return c.m["authorized-keys"].(string)
  }

+// AgentVersion returns the proposed version number for the agent tools.
+// It returns the zero version if unset.
+func (c *Config) AgentVersion() version.Number {
+	v, ok := c.m["agent-version"].(string)
+	if !ok {
+		return version.Number{}
+	}
+	n, err := version.Parse(v)
+	if err != nil {
+		panic(err)		// We should have checked it earlier.
+	}
+	return n
+}
+
  // UnknownAttrs returns a copy of the raw configuration attributes
  // that are supposedly specific to the environment type. They could
  // also be wrong attributes, though. Only the specific environment
@@ -112,12 +133,14 @@
  	"default-series":       schema.String(),
  	"authorized-keys":      schema.String(),
  	"authorized-keys-path": schema.String(),
+	"agent-version": schema.String(),
  }

  var defaults = schema.Defaults{
  	"default-series":       version.Current.Series,
  	"authorized-keys":      "",
  	"authorized-keys-path": "",
+	"agent-version": schema.Omit,
  }

  var checker = schema.FieldMap(fields, defaults)


Index: environs/config/config_test.go
=== modified file 'environs/config/config_test.go'
--- environs/config/config_test.go	2012-08-02 08:29:38 +0000
+++ environs/config/config_test.go	2012-08-30 09:11:09 +0000
@@ -70,6 +70,22 @@
  		"",
  	}, {
  		attrs{
+			"type":	"my-type",
+			"name":            "my-name",
+			"authorized-keys": "my-keys",
+			"agent-version": "1.2.3",
+		},
+		"",
+	}, {
+		attrs{
+			"type":	"my-type",
+			"name":            "my-name",
+			"authorized-keys": "my-keys",
+			"agent-version": "2",
+		},
+		`invalid agent version in environment configuration: "2"`,
+	}, {
+		attrs{
  			"name": "my-name",
  		},
  		"type: expected string, got nothing",
@@ -90,7 +106,8 @@
  			"name": "",
  		},
  		"empty name in environment configuration",
-	}}
+	},
+}

  func (*ConfigSuite) TestConfig(c *C) {
  	homedir := c.MkDir()
@@ -114,7 +131,8 @@
  		c.Assert(err, IsNil)
  	}

-	for _, test := range configTests {
+	for i, test := range configTests {
+		c.Logf("test %d", i)
  		cfg, err := config.New(test.attrs)
  		if test.err != "" {
  			c.Assert(err, ErrorMatches, test.err)
@@ -127,7 +145,13 @@
  		name, _ := test.attrs["name"].(string)
  		c.Assert(cfg.Type(), Equals, typ)
  		c.Assert(cfg.Name(), Equals, name)
-
+		if s := test.attrs["agent-version"]; s != nil {
+			vers, err := version.Parse(s.(string))
+			c.Assert(err, IsNil)
+			c.Assert(cfg.AgentVersion(), Equals, vers)
+		} else {
+			c.Assert(cfg.AgentVersion(), Equals, version.Number{})
+		}
  		if series, _ := test.attrs["default-series"].(string); series != "" {
  			c.Assert(cfg.DefaultSeries(), Equals, series)
  		} else {