public SpotPrice unmarshall(StaxUnmarshallerContext context) throws Exception {
SpotPrice spotPrice = new SpotPrice();
int originalDepth = context.getCurrentDepth();
int targetDepth = originalDepth + 1;
if (context.isStartOfDocument()) targetDepth += 1;
while (true) {
XMLEvent xmlEvent = context.nextEvent();
if (xmlEvent.isEndDocument()) return spotPrice;
if (xmlEvent.isAttribute() || xmlEvent.isStartElement()) {
if (context.testExpression("instanceType", targetDepth)) {
spotPrice.setInstanceType(StringStaxUnmarshaller.getInstance().unmarshall(context));
continue;
}
if (context.testExpression("productDescription", targetDepth)) {
spotPrice.setProductDescription(StringStaxUnmarshaller.getInstance().unmarshall(context));
continue;
}
if (context.testExpression("spotPrice", targetDepth)) {
spotPrice.setSpotPrice(StringStaxUnmarshaller.getInstance().unmarshall(context));
continue;
}
if (context.testExpression("timestamp", targetDepth)) {
spotPrice.setTimestamp(DateStaxUnmarshaller.getInstance().unmarshall(context));
continue;
}
if (context.testExpression("availabilityZone", targetDepth)) {
spotPrice.setAvailabilityZone(StringStaxUnmarshaller.getInstance().unmarshall(context));
continue;
}
} else if (xmlEvent.isEndElement()) {
if (context.getCurrentDepth() < originalDepth) {
return spotPrice;
}
}
}
}
/*
* Check the current Spot price of the selected instance type for the selected region
*/
public FormValidation doCurrentSpotPrice(
@QueryParameter boolean useInstanceProfileForCredentials,
@QueryParameter String credentialsId,
@QueryParameter String region,
@QueryParameter String type,
@QueryParameter String zone)
throws IOException, ServletException {
String cp = "";
String zoneStr = "";
// Connect to the EC2 cloud with the access id, secret key, and
// region queried from the created cloud
AWSCredentialsProvider credentialsProvider =
EC2Cloud.createCredentialsProvider(useInstanceProfileForCredentials, credentialsId);
AmazonEC2 ec2 =
EC2Cloud.connect(credentialsProvider, AmazonEC2Cloud.getEc2EndpointUrl(region));
if (ec2 != null) {
try {
// Build a new price history request with the currently
// selected type
DescribeSpotPriceHistoryRequest request = new DescribeSpotPriceHistoryRequest();
// If a zone is specified, set the availability zone in the
// request
// Else, proceed with no availability zone which will result
// with the cheapest Spot price
if (getAvailabilityZones(ec2).contains(zone)) {
request.setAvailabilityZone(zone);
zoneStr = zone + " availability zone";
} else {
zoneStr = region + " region";
}
/*
* Iterate through the AWS instance types to see if can find a match for the databound String type.
* This is necessary because the AWS API needs the instance type string formatted a particular way
* to retrieve prices and the form gives us the strings in a different format. For example "T1Micro"
* vs "t1.micro".
*/
InstanceType ec2Type = null;
for (InstanceType it : InstanceType.values()) {
if (it.name().equals(type)) {
ec2Type = it;
break;
}
}
/*
* If the type string cannot be matched with an instance type, throw a Form error
*/
if (ec2Type == null) {
return FormValidation.error("Could not resolve instance type: " + type);
}
Collection<String> instanceType = new ArrayList<String>();
instanceType.add(ec2Type.toString());
request.setInstanceTypes(instanceType);
request.setStartTime(new Date());
// Retrieve the price history request result and store the
// current price
DescribeSpotPriceHistoryResult result = ec2.describeSpotPriceHistory(request);
if (!result.getSpotPriceHistory().isEmpty()) {
SpotPrice currentPrice = result.getSpotPriceHistory().get(0);
cp = currentPrice.getSpotPrice();
}
} catch (AmazonServiceException e) {
return FormValidation.error(e.getMessage());
}
}
/*
* If we could not return the current price of the instance display an error Else, remove the additional
* zeros from the current price and return it to the interface in the form of a message
*/
if (cp.isEmpty()) {
return FormValidation.error("Could not retrieve current Spot price");
} else {
cp = cp.substring(0, cp.length() - 3);
return FormValidation.ok(
"The current Spot price for a " + type + " in the " + zoneStr + " is $" + cp);
}
}
