feat(config-resolver): resolve hostname from variants

[trivikr]

Issue

Internal JS-2929

Description

Uses variants for getting region info

• getRegionInfo fetches regionHostname and partitionHostname from respective variants.
• getRegionInfo throws error is hostname is undefined.

Testing

• Unit testing
• Functional testing

Code used for populating functional tests

// The models directory smithy models
// from https://github.com/aws/aws-sdk-js-v3/tree/main/codegen/sdk-codegen/aws-models
// The endpoints.json contains RIP endpoints.

// In JS SDK v3, the test case for SimpleDB and mobileanalytics is removed as they're deprecated.

import { readFile, readdir, writeFile } from "fs/promises";

const findVal = (object, key) => {
  let value;
  Object.keys(object).some((k) => {
    if (k === key) {
      value = object[k];
      return true;
    }
    if (object[k] && typeof object[k] === "object") {
      value = findVal(object[k], key);
      return value !== undefined;
    }
  });
  return value;
};

const getServiceInfo = (api) => {
  return findVal(api, "aws.api#service");
};

const endpointPrefixSdkIdHash = {};
const models = await readdir("models");
for (const modelFileName of models) {
  const model = JSON.parse(
    (await readFile(`models/${modelFileName}`)).toString()
  );
  const { endpointPrefix, sdkId } = getServiceInfo(model);
  endpointPrefixSdkIdHash[endpointPrefix] = sdkId;
}

// Add exceptions
endpointPrefixSdkIdHash["rds"] = "RDS";
endpointPrefixSdkIdHash["docdb"] = "DocDB";
endpointPrefixSdkIdHash["neptune"] = "Neptune";
endpointPrefixSdkIdHash["importexport"] = "S3";
endpointPrefixSdkIdHash["ioteventsdata"] = "IoT Events Data";
endpointPrefixSdkIdHash["iotsecuredtunneling"] = "IoTSecureTunneling";
endpointPrefixSdkIdHash["iotwireless"] = "IoT Wireless";
endpointPrefixSdkIdHash["mobileanalytics"] = "Pinpoint";
endpointPrefixSdkIdHash["sdb"] = "SimpleDB";

const getHostnameWithDnsSuffix = (template, dnsSuffix) =>
  template.replace("{dnsSuffix}", dnsSuffix || "{dnsSuffix}");

const getVariantsWithDnsSuffix = (variants = [], parentDnsSuffix) =>
  variants.map(({ hostname, dnsSuffix, tags }) => ({
    hostname: getHostnameWithDnsSuffix(hostname, dnsSuffix || parentDnsSuffix),
    tags,
  }));

const getHostname = (variants, { isFipsEndpoint, isDualstackEndpoint }) =>
  variants.find(
    ({ tags }) =>
      isFipsEndpoint === tags.includes("fips") &&
      isDualstackEndpoint === tags.includes("dualstack")
  )?.hostname;

const testCases = [];
const endpoints = JSON.parse((await readFile("endpoints.json")).toString());
for (const partition of endpoints.partitions) {
  const partitionDnsSuffix = partition.dnsSuffix;
  const partitionVariants = getVariantsWithDnsSuffix(
    partition.defaults.variants,
    partitionDnsSuffix
  );
  if (partition.defaults.hostname) {
    partitionVariants.push({
      hostname: getHostnameWithDnsSuffix(
        partition.defaults.hostname,
        partitionDnsSuffix
      ),
      tags: [],
    });
  }

  for (const [endpointPrefix, serviceConfig] of Object.entries(
    partition.services
  )) {
    const serviceDnsSuffix = serviceConfig.dnsSuffix;
    const serviceVariants = getVariantsWithDnsSuffix(
      serviceConfig.defaults?.variants,
      serviceDnsSuffix || partitionDnsSuffix
    );
    if (serviceConfig.hostname) {
      serviceVariants.push({
        hostname: getHostnameWithDnsSuffix(
          serviceConfig.hostname,
          serviceDnsSuffix
        ),
        tags: [],
      });
    }

    for (const isFipsEndpoint of [false, true]) {
      for (const isDualstackEndpoint of [false, true]) {
        const options = { isFipsEndpoint, isDualstackEndpoint };
        const partitionHostname = getHostname(partitionVariants, options);
        const serviceHostname = getHostname(serviceVariants, options);

        const notSupportedByService =
          serviceVariants.length > 0 && serviceHostname === undefined;
        if (notSupportedByService) {
          continue;
        }

        let hostnameFromParentCase = partitionHostname === undefined;
        let hostnameFromEndpointCase = false;

        for (const [region, regionConfig] of Object.entries(
          serviceConfig.endpoints
        )) {
          if (hostnameFromParentCase && hostnameFromEndpointCase) {
            break;
          }

          const { hostname, variants, deprecated } = regionConfig;
          if (deprecated) {
            continue;
          }

          if (!hostnameFromEndpointCase && variants) {
            if (hostname) {
              variants.push({
                hostname: getHostnameWithDnsSuffix(hostname),
                tags: [],
              });
            }

            const endpointHostname = getHostname(variants, options);
            if (endpointHostname) {
              testCases.push({
                endpointPrefix,
                sdkId: endpointPrefixSdkIdHash[endpointPrefix],
                region,
                isFipsEndpoint,
                isDualstackEndpoint,
                hostname: endpointHostname,
              });
              hostnameFromEndpointCase = true;
            }
          } else if (!hostnameFromParentCase && !variants && !hostname) {
            testCases.push({
              endpointPrefix,
              sdkId: endpointPrefixSdkIdHash[endpointPrefix],
              region,
              isFipsEndpoint,
              isDualstackEndpoint,
              hostname: (serviceHostname || partitionHostname)
                .replace("{region}", region)
                .replace("{service}", endpointPrefix),
            });
            hostnameFromParentCase = true;
          }
        }
      }
    }
  }
}
await writeFile("testCases.json", JSON.stringify(testCases, null, 2));

---

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[codecov-commenter]

Codecov Report

Merging #2980 (f703ba7) into main (ba4386d) will increase coverage by 0.02%.
The diff coverage is 100.00%.

❗ Current head f703ba7 differs from pull request most recent head ec28c27. Consider uploading reports for the commit ec28c27 to get more accurate results

@@            Coverage Diff             @@
##             main    #2980      +/-   ##
==========================================
+ Coverage   58.70%   58.72%   +0.02%     
==========================================
  Files         566      566              
  Lines       30315    30330      +15     
  Branches     7460     7469       +9     
==========================================
+ Hits        17796    17811      +15     
  Misses      12519    12519              

Impacted Files	Coverage Δ
...resolver/src/regionInfo/getHostnameFromVariants.ts	100.00% <100.00%> (ø)
...es/config-resolver/src/regionInfo/getRegionInfo.ts	100.00% <100.00%> (ø)
...fig-resolver/src/regionInfo/getResolvedHostname.ts	100.00% <100.00%> (ø)

---

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[AllanZhengYP]

Re-approve it!

[github-actions]

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