Request higher SafeLevel builds when requesting Android build by branch

In cvd fetch, when requesting a build by branch and target, prefer
requesting higher SafeLevel builds (PLATINUM, SAFE_2, SAFE_1) when
possible before falling back to any complete successful build (SAFE_0 /
unspecified).

If users want a specific build id, that is already possible to request
through command line arguments. When a user requests a branch by name,
they probably do not care as much how recent the build is.

The main failure mode here is if a build target / branch combination has
previously reported a higher safe level and no longer does, it will get
stuck on the older build from the higher safe level indefinitely.

Assisted-by: Jetski:Gemini Next
Bug: b/518049553

Author: Databean

base/cvd/cuttlefish/host/libs/web/android_build_api.cpp

@@ -276,25 +276,25 @@ Result<std::vector<std::string>> AndroidBuildApi::Headers() {
 
 Result<std::optional<std::string>> AndroidBuildApi::LatestBuildId(
     const std::string& branch, const std::string& target) {
-  const std::string url =
-      android_build_url_->GetLatestBuildIdUrl(branch, target);
-  auto response =
-      CF_EXPECT(HttpGetToJson(http_client_, url, CF_EXPECT(Headers())));
-
-  const Json::Value json = CF_EXPECTF(GetResponseJson(response),
-                                      "Error fetching last known good build "
-                                      "id for:\nbranch \"{}\", target \"{}\"",
-                                      branch, target);
-  if (!json.isMember("builds")) {
-    return std::nullopt;
+  for (const std::string_view safe_level :
+       {"PLATINUM", "SAFE_2", "SAFE_1", ""}) {
+    const std::string url =
+        android_build_url_->GetLatestBuildIdUrl(branch, target, safe_level);
+    std::vector<std::string> headers = CF_EXPECT(Headers());
+    HttpResponse<Json::Value> response =
+        CF_EXPECT(HttpGetToJson(http_client_, url, headers));
+
+    const Json::Value json = CF_EXPECTF(
+        GetResponseJson(response),
+        "Error fetching last known good build id for:\nbranch \"{}\", target "
+        "\"{}\", safe_level \"{}\"",
+        branch, target, safe_level);
+    if (json.isMember("builds") && json["builds"].isArray() &&
+        !json["builds"].empty()) {
+      return CF_EXPECT(GetValue<std::string>(json["builds"][0], {"buildId"}));
+    }
   }
-
-  CF_EXPECTF(json["builds"].isArray() && json["builds"].size() == 1,
-             "Expected to find a single latest build for branch \"{}\" and "
-             "target \"{}\" in the response array, "
-             "but found {}",
-             branch, target, json["builds"].size());
-  return CF_EXPECT(GetValue<std::string>(json["builds"][0], { "buildId" }));
+  return std::nullopt;
 }
 
 Result<std::unordered_set<std::string>> AndroidBuildApi::Artifacts(

base/cvd/cuttlefish/host/libs/web/android_build_url.cpp

@@ -116,12 +116,16 @@ AndroidBuildUrl::AndroidBuildUrl(std::string api_base_url, std::string api_key,
       project_id_(std::move(project_id)) {}
 
 std::string AndroidBuildUrl::GetLatestBuildIdUrl(std::string_view branch,
-                                                 std::string_view target) {
+                                                 std::string_view target,
+                                                 std::string_view safe_level) {
   UrlBuilder builder = UrlBuilder::GetLatestBuildIdBaseUrl(api_base_url_);
   builder.AddQueryParameter("buildAttemptStatus", "complete");
   builder.AddQueryParameter("buildType", "submitted");
   builder.AddQueryParameter("pageSize", "1");
   builder.AddQueryParameter("successful", "true");
+  if (!safe_level.empty()) {
+    builder.AddQueryParameter("safeLevel", safe_level);
+  }
   builder.AddQueryParameter("branches", branch);
   builder.AddQueryParameter("targets", target);
   builder.AddApiKeyAndProjectId(api_key_, project_id_);

base/cvd/cuttlefish/host/libs/web/android_build_url.h

@@ -30,7 +30,8 @@ class AndroidBuildUrl {
                   std::string project_id);
 
   std::string GetLatestBuildIdUrl(std::string_view branch,
-                                  std::string_view target);
+                                  std::string_view target,
+                                  std::string_view safe_level = "");
   std::string GetBuildUrl(std::string_view id, std::string_view target);
   std::string GetArtifactUrl(std::string_view id, std::string_view target,
                              const std::vector<std::string>& artifact_filenames,