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Unmarshal instance metadata JSON #40

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Unmarshal instance metadata JSON #40

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a5cca36
Unmarshal instance metadata JSON
tianxiaoliang Aug 5, 2016
bb80962
Update marshal.go
tianxiaoliang Aug 31, 2016
cfebc47
Update marshal.go
tianxiaoliang Aug 31, 2016
a67a27c
Ummarshal Metadata json and Export parsed metadata
Sep 1, 2016
558b027
Ummarshal Metadata json and Export parsed metadata
Sep 1, 2016
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15 changes: 10 additions & 5 deletions marshal.go
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Original file line number Diff line number Diff line change
Expand Up @@ -105,14 +105,19 @@ func parsePort(s string) int {
// the raw JSON for later parsing.
func (i *InstanceMetadata) UnmarshalJSON(b []byte) error {
i.Raw = b
// TODO(cq) could actually parse Raw here, and in a parallel UnmarshalXML as well.
// TODO(cq) could actually parse Raw in a parallel UnmarshalXML as well.
var m map[string]interface{}
if err := json.Unmarshal(b, &m); err != nil {
return err
}
i.Parsed = m
return nil
}

// MarshalJSON is a custom JSON marshaler for InstanceMetadata.
func (i *InstanceMetadata) MarshalJSON() ([]byte, error) {
if i.parsed != nil {
return json.Marshal(i.parsed)
if i.Parsed != nil {
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@seh seh Sep 6, 2016

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Should that be checking the entry count instead? That is, if there's a map instance present, but it's empty, should that still be marshaled?

if len(i.Parsed) > 0 {

return json.Marshal(i.Parsed)
}

if i.Raw == nil {
Expand All @@ -126,8 +131,8 @@ func (i *InstanceMetadata) MarshalJSON() ([]byte, error) {
func (i InstanceMetadata) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
tokens := []xml.Token{start}

if i.parsed != nil {
for key, value := range i.parsed {
if i.Parsed != nil {
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@seh seh Sep 6, 2016

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The same comment about checking the entry count applies here. But note that the range expression on line 135 would still work fine (that is, never executing the surrounding for expression's body) against a nil or empty map reference.

for key, value := range i.Parsed {
t := xml.StartElement{Name: xml.Name{"", key}}
tokens = append(tokens, t, xml.CharData(value.(string)), xml.EndElement{t.Name})
}
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16 changes: 8 additions & 8 deletions metadata.go
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Original file line number Diff line number Diff line change
Expand Up @@ -23,23 +23,23 @@ func (a *Application) ParseAllMetadata() error {

// SetMetadataString for a given instance before register
func (ins *Instance) SetMetadataString(key, value string) {
if ins.Metadata.parsed == nil {
ins.Metadata.parsed = map[string]interface{}{}
if ins.Metadata.Parsed == nil {
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@seh seh Sep 1, 2016

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Given that we can set entries in this field, "Parsed" doesn't match its use. "Parsed" implies that we only receive these values.

Again, consider renaming it to "Map", "Fields", "Values", or something similar.

ins.Metadata.Parsed = map[string]interface{}{}
}
ins.Metadata.parsed[key] = value
ins.Metadata.Parsed[key] = value
}

func (im *InstanceMetadata) parse() error {
if len(im.Raw) == 0 {
im.parsed = make(map[string]interface{})
im.Parsed = make(map[string]interface{})
log.Debug("len(Metadata)==0. Quitting parsing.")
return nil
}
metadataLog.Debugf("InstanceMetadata.parse: %s", im.Raw)

if len(im.Raw) > 0 && im.Raw[0] == '{' {
// JSON
err := json.Unmarshal(im.Raw, &im.parsed)
err := json.Unmarshal(im.Raw, &im.Parsed)
if err != nil {
log.Errorf("Error unmarshalling: %s", err.Error())
return fmt.Errorf("error unmarshalling: %s", err.Error())
Expand All @@ -52,22 +52,22 @@ func (im *InstanceMetadata) parse() error {
log.Errorf("Error unmarshalling: %s", err.Error())
return fmt.Errorf("error unmarshalling: %s", err.Error())
}
im.parsed = parsedDoc["d"].(map[string]interface{})
im.Parsed = parsedDoc["d"].(map[string]interface{})
}
return nil
}

// GetMap returns a map of the metadata parameters for this instance
func (im *InstanceMetadata) GetMap() map[string]interface{} {
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@seh seh Sep 1, 2016

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Now that the underlying field is exported, this method isn't necessary, but I doubt we can get away with removing it, as that would break existing callers.

return im.parsed
return im.Parsed
}

func (im *InstanceMetadata) getItem(key string) (interface{}, bool, error) {
err := im.parse()
if err != nil {
return "", false, fmt.Errorf("parsing error: %s", err.Error())
}
val, present := im.parsed[key]
val, present := im.Parsed[key]
return val, present, nil
}

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2 changes: 1 addition & 1 deletion struct.go
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Original file line number Diff line number Diff line change
Expand Up @@ -113,7 +113,7 @@ type Port struct {
// metadata.go for more info.
type InstanceMetadata struct {
Raw []byte `xml:",innerxml" json:"-"`
parsed map[string]interface{}
Parsed map[string]interface{} `json:"-"`
}

// AmazonMetadataType is information about AZ's, AMI's, and the AWS instance
Expand Down