void updateTags()

in aws-iot-fleetmetric/src/main/java/com/amazonaws/iot/fleetmetric/UpdateHandler.java [96:160]
44 lines of code
5 McCabe index (conditional complexity)

    void updateTags(AmazonWebServicesClientProxy proxy,
                    ResourceHandlerRequest<ResourceModel> request,
                    String resourceArn,
                    Logger logger) {
        // Note: we're intentionally getting currentTags by calling ListTags rather than getting
        // the previous state from CFN. This is in order to overwrite out-of-band changes.
        // For example, if we used request.getPreviousResourceTags instead of ListTags, if a user added a new tag
        // via TagResource and didn't add it to the template, we wouldn't know about it and wouldn't untag it.
        // Yet we should, otherwise the resource wouldn't equate the template.
        Set<Tag> currentTags = listTags(proxy, resourceArn, logger);

        // Combine all tags in one map that we'll use for the request
        Map<String, String> allDesiredTagsMap = new HashMap<>();
        if (request.getDesiredResourceTags() != null) {
            // DesiredResourceTags includes both model and stack-level tags.
            // Reference: https://tinyurl.com/yyxtd7w6
            // TODO add system tags back once FleetMetric auth is ready
            // allDesiredTagsMap.putAll(request.getDesiredResourceTags());
            request.getDesiredResourceTags().entrySet().stream()
                    .filter(e -> !e.getKey().startsWith(AWS_SYSTEM_TAG_PREFIX))
                    .forEach(e -> allDesiredTagsMap.put(e.getKey(), e.getValue()));
        }
        if (request.getSystemTags() != null) {
            // There are also system tags provided separately.
            // SystemTags are the default stack-level tags with aws:cloudformation prefix.
            // TODO add system tags back once FleetMetric auth is ready
            // allDesiredTagsMap.putAll(request.getSystemTags());
        } else {
            // System tags should never get updated as they are the stack id, stack name,
            // and logical resource id.
            logger.log("Unexpectedly, system tags are null in the update request for " + resourceArn);
        }
        Set<Tag> desiredTags = Translator.translateTagsToSdk(allDesiredTagsMap);
        Set<String> desiredTagKeys = desiredTags.stream()
                .map(Tag::key)
                .collect(Collectors.toSet());

        // TODO add system tags back once FleetMetric auth is ready
        Set<String> tagKeysToDetach = currentTags.stream()
                .filter(tag -> !tag.key().startsWith(AWS_SYSTEM_TAG_PREFIX))
                .filter(tag -> !desiredTagKeys.contains(tag.key()))
                .map(Tag::key)
                .collect(Collectors.toSet());
        Set<Tag> tagsToAttach = desiredTags.stream()
                .filter(tag -> !currentTags.contains(tag))
                .collect(Collectors.toSet());

        if (!tagsToAttach.isEmpty()) {
            TagResourceRequest tagResourceRequest = TagResourceRequest.builder()
                    .resourceArn(resourceArn)
                    .tags(tagsToAttach)
                    .build();
            proxy.injectCredentialsAndInvokeV2(tagResourceRequest, iotClient::tagResource);
            logger.log(String.format("Called TagResource for %s.", resourceArn));
        }

        if (!tagKeysToDetach.isEmpty()) {
            UntagResourceRequest untagResourceRequest = UntagResourceRequest.builder()
                    .resourceArn(resourceArn)
                    .tagKeys(tagKeysToDetach)
                    .build();
            proxy.injectCredentialsAndInvokeV2(untagResourceRequest, iotClient::untagResource);
            logger.log(String.format("Called UntagResource for %s.", resourceArn));
        }
    }