apache/beam · error · NoSuchElementException

Failed to list first page of FHIR resources from

Error message

Failed to list first page of FHIR resources from %s: %s

What it means

The FHIR store 'has any resources' check in HttpHealthcareApiClient throws NoSuchElementException when the initial FHIR search request throws IOException, converting an I/O/API failure into an empty-result signal for the hasNext() contract. The real cause (store not found, no permission, malformed request) is appended in the message.

Solutions

Verify the fhirStore full resource path (projects/{p}/locations/{l}/datasets/{d}/fhirStores/{s})
Grant roles/healthcare.fhirStoreViewer to the caller's service account
Check the embedded IOException message for the actual HTTP cause
Confirm the FHIR store exists via `gcloud healthcare fhir-stores describe` and retry on transient failures

Example fix

// before
throw new NoSuchElementException(String.format("Failed to list first page of FHIR resources from %s: %s", fhirStore, e.getMessage()));
// after
// validate store accessibility before iterating
try {
  boolean hasResources = client.hasFhirResources(fhirStore);
} catch (NoSuchElementException e) {
  throw new IOException("Cannot access FHIR store " + fhirStore + ": " + e.getMessage(), e);
}

Defensive patterns

Strategy: try-catch

Validate before calling

java
if (!fhirStore.matches("projects/[^/]+/locations/[^/]+/datasets/[^/]+/fhirStores/[^/]+")) {
  throw new IllegalArgumentException("Malformed fhirStore path: " + fhirStore);
}

Try / catch

java
try {
  hasResources = checkFirstPage(fhirStore);
} catch (NoSuchElementException e) {
  throw new IOException("FHIR store unreachable: " + e.getMessage(), e);
}

Prevention

Verify the FHIR store exists and IAM read access before running the pipeline
Catch NoSuchElementException and rethrow with the embedded cause for diagnosability
Retry transient failures with backoff
Confirm store region/location matches the client's endpoint

When it happens

Trigger: Calling the method that checks for the first page of FHIR resources (used by FhirIO source hasNext) when the FHIR stores.search/.list REST request fails: wrong fhirStore path, missing healthcare.fhirStoreViewer IAM role, network outage, or API error response.

Common situations: Misspelled datasets/{d}/fhirStores/{s} path; service account without FHIR read permissions; transient 5xx during a Beam FHIR import/export pipeline; FHIR store not yet created.

Understand the failure class

Background: "API error: {status}" and "HTTP 401/403/404/429/5xx" errors: non-2xx HTTP responses explained — this error's family across 27 libraries.

Related errors

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/aadf3601d3ca934f. Report an issue: GitHub.

Appendix: source

Thrown at sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/healthcare/HttpHealthcareApiClient.java:976

    public static FhirResourcePagesIterator ofPatientEverything(
        HealthcareApiClient client, String resourceName, @Nullable Map<String, Object> parameters) {
      return new FhirResourcePagesIterator(
          FhirMethod.PATIENT_EVERYTHING, client, "", "", resourceName, parameters);
    }

    @Override
    public boolean hasNext() throws NoSuchElementException {
      if (!isFirstRequest) {
        return this.pageToken != null && !this.pageToken.isEmpty();
      }
      try {
        HttpBody response = executeFhirRequest();
        JsonObject jsonResponse =
            JsonParser.parseString(mapper.writeValueAsString(response)).getAsJsonObject();
        JsonArray resources = jsonResponse.getAsJsonArray("entry");
        return resources != null && resources.size() != 0;
      } catch (IOException e) {
        throw new NoSuchElementException(
            String.format(
                "Failed to list first page of FHIR resources from %s: %s",
                fhirStore, e.getMessage()));
      }
    }

    @Override
    public JsonArray next() throws NoSuchElementException {
      try {
        HttpBody response = executeFhirRequest();
        this.isFirstRequest = false;
        JsonObject jsonResponse =
            JsonParser.parseString(mapper.writeValueAsString(response)).getAsJsonObject();
        JsonArray links = jsonResponse.getAsJsonArray("link");
        this.pageToken = parsePageToken(links);
        JsonArray resources = jsonResponse.getAsJsonArray("entry");
        return resources;
      } catch (IOException e) {

View on GitHub (pinned to 12126d8942)