feat(go_server): Add support for labeled_boolean

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Go server: Add support for `labeled_boolean` metrics with static labels ([AE-1250](https://mozilla-hub.atlassian.net/browse/AE-1250))
+
 ## 19.0.0
 
 - Python server: Support optional metrics ([#828](https://github.com/mozilla/glean_parser/pull/828))

glean_parser/go_server.py

@@ -38,6 +38,7 @@
     "event",
     "datetime",
     "boolean",
+    "labeled_boolean",  # static labels only; dynamic labels are not supported
     "string_list",
 ]
 
@@ -87,6 +88,28 @@ def clean_string(s: str) -> str:
     return s.replace("\n", " ").rstrip()
 
 
+def validate_labeled_boolean(metric: metrics.Metric) -> bool:
+    """
+    Validate that a labeled_boolean metric has static labels defined.
+
+    The Go server outputter requires labels to be listed in metrics.yaml
+    because it generates a Go struct with a field per label at build time.
+    Dynamic labels are not supported.
+
+    Returns:
+        bool: True if valid, False otherwise
+    """
+    if not getattr(metric, "ordered_labels", None):
+        print(
+            "❌ Ignoring labeled_boolean metric without static labels: "
+            + f"{metric.name}."
+            + " Define labels in metrics.yaml to use this metric type."
+        )
+        return False
+
+    return True
+
+
 def output_go(
     objs: metrics.ObjectTree, output_dir: Path, options: Optional[Dict[str, Any]]
 ) -> None:
@@ -118,6 +141,9 @@ def output_go(
     # unique list of event metrics used in any ping
     event_metrics: List[metrics.Metric] = []
 
+    # unique list of labeled_boolean metrics used in any ping
+    labeled_boolean_metrics: List[metrics.Metric] = []
+
     # Go through all metrics in objs and build a map of
     # ping->list of metric categories->list of metrics
     # for easier processing in the template.
@@ -134,10 +160,22 @@ def output_go(
                     )
                     continue
 
+                # Validate labeled_boolean metrics
+                if metric.type == "labeled_boolean" and not validate_labeled_boolean(
+                    metric
+                ):
+                    continue
+
                 for ping in metric.send_in_pings:
                     if metric.type == "event" and metric not in event_metrics:
                         event_metrics.append(metric)
 
+                    if (
+                        metric.type == "labeled_boolean"
+                        and metric not in labeled_boolean_metrics
+                    ):
+                        labeled_boolean_metrics.append(metric)
+
                     metrics_by_type = ping_to_metrics[ping]
                     metrics_list = metrics_by_type.setdefault(metric.type, [])
                     metrics_list.append(metric)
@@ -156,6 +194,9 @@ def output_go(
     with filepath.open("w", encoding="utf-8") as fd:
         fd.write(
             template.render(
-                parser_version=__version__, pings=ping_to_metrics, events=event_metrics
+                parser_version=__version__,
+                pings=ping_to_metrics,
+                events=event_metrics,
+                labeled_booleans=labeled_boolean_metrics,
             )
         )

glean_parser/templates/go_server.jinja2

@@ -220,6 +220,18 @@ func (e {{ event|event_type_name }}) gleanEvent() gleanEvent {
 }
 {% endfor %}
 {% endif %}
+{# Generate struct types for labeled_boolean metrics #}
+{% if labeled_booleans %}
+{% for metric in labeled_booleans %}
+
+// {{ metric.description|clean_string }}
+type {{ metric|metric_argument_name }} struct {
+    {% for label in metric.ordered_labels %}
+    {{ label|event_extra_name }} bool // {{ label }}
+    {% endfor %}
+}
+{% endfor %}
+{% endif %}
 {# struct & methods for submitting pings #}
 {% for ping, metrics_by_type in pings.items() %}
 {% if metrics_by_type['event'] %}
@@ -240,7 +252,11 @@ type {{ ping|ping_type_name }} struct {
     {% for metric_type, metrics in metrics_by_type.items() %}
     {% if metric_type != 'event' %}
     {% for metric in metrics %}
+    {% if metric_type == 'labeled_boolean' %}
+    {{ metric|metric_argument_name }} {{ metric|metric_argument_name }} // {{ metric.description|clean_string }}
+    {% else %}
     {{ metric|metric_argument_name }} {{ metric_type|go_metric_type}} // {{ metric.description|clean_string }}
+    {% endif %}
     {% endfor %}
     {% endif %}
     {% endfor %}
@@ -261,6 +277,12 @@ func (g GleanEventsLogger) Record{{ ping|ping_type_name }}(
         {% for metric in metrics %}
             {% if metric_type == 'datetime' %}
             "{{ metric|metric_name }}": params.{{ metric|metric_argument_name }}.Format("2006-01-02T15:04:05.000Z"),
+            {% elif metric_type == 'labeled_boolean' %}
+            "{{ metric|metric_name }}": map[string]bool{
+                {% for label in metric.ordered_labels %}
+                "{{ label }}": params.{{ metric|metric_argument_name }}.{{ label|event_extra_name }},
+                {% endfor %}
+            },
             {% else %}
             "{{ metric|metric_name }}": params.{{ metric|metric_argument_name }},
             {% endif %}

tests/data/go_server_labeled_boolean_metrics.yaml

@@ -0,0 +1,25 @@
+# Any copyright is dedicated to the Public Domain.
+# https://creativecommons.org/publicdomain/zero/1.0/
+
+---
+$schema: moz://mozilla.org/schemas/glean/metrics/2-0-0
+
+telemetry:
+  feature_flags:
+    type: labeled_boolean
+    description: >
+      Feature flags for A/B testing
+    labels:
+      - feature_one
+      - feature_two
+      - feature_three
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1234567
+    data_reviews:
+      - https://example.com/review
+    notification_emails:
+      - telemetry@example.com
+    lifetime: application
+    expires: never
+    send_in_pings:
+      - events

tests/test_go_server.py

@@ -39,8 +39,6 @@ def test_parser_go_server_metrics_unsupported_type(tmp_path, capsys):
     captured = capsys.readouterr()
     assert "Ignoring unsupported metric type" in captured.out
     unsupported_types = [
-        "boolean",
-        "labeled_boolean",
         "labeled_string",
         "timespan",
         "uuid",
@@ -50,6 +48,49 @@ def test_parser_go_server_metrics_unsupported_type(tmp_path, capsys):
         assert t in captured.out
 
 
+def test_parser_go_server_labeled_boolean_without_labels(tmp_path, capsys):
+    """Test that labeled_boolean without static labels is rejected."""
+    translate.translate(
+        [
+            ROOT / "data" / "go_server_metrics_unsupported.yaml",
+        ],
+        "go_server",
+        tmp_path,
+    )
+    captured = capsys.readouterr()
+    assert "Ignoring labeled_boolean metric without static labels" in captured.out
+
+
+def test_parser_go_server_labeled_boolean(tmp_path):
+    """Test that labeled_boolean metrics generate proper struct types."""
+    translate.translate(
+        ROOT / "data" / "go_server_labeled_boolean_metrics.yaml",
+        "go_server",
+        tmp_path,
+    )
+
+    assert set(x.name for x in tmp_path.iterdir()) == set(["server_events.go"])
+
+    # Read generated file and verify struct is created
+    with (tmp_path / "server_events.go").open("r", encoding="utf-8") as fd:
+        content = fd.read()
+
+        # Check that the labeled_boolean struct type was generated
+        assert "type TelemetryFeatureFlags struct {" in content
+        assert "FeatureOne bool" in content
+        assert "FeatureTwo bool" in content
+        assert "FeatureThree bool" in content
+
+        # Check that it's used in the ping struct
+        assert "TelemetryFeatureFlags TelemetryFeatureFlags" in content
+
+        # Check that serialization includes map creation
+        assert "map[string]bool{" in content
+        assert '"feature_one":' in content
+        assert '"feature_two":' in content
+        assert '"feature_three":' in content
+
+
 def test_parser_go_server_events_only(tmp_path):
     """Test that parser works for definitions that only use events ping"""
     translate.translate(
@@ -344,6 +385,67 @@ def test_run_logging_nil_writer(tmp_path):
     assert logged_output == "writer not specified\n"
 
 
+@pytest.mark.go_dependency
+def test_run_logging_labeled_boolean(tmp_path):
+    glean_module_path = tmp_path / "glean"
+
+    translate.translate(
+        [
+            ROOT / "data" / "go_server_labeled_boolean_metrics.yaml",
+        ],
+        "go_server",
+        glean_module_path,
+    )
+
+    code = """
+    _ = time.Now() // satisfy Go's unused import check for "time"
+    logger.RecordEventsPing(
+        glean.RequestInfo{
+            UserAgent: "glean-test/1.0",
+            IpAddress: "127.0.0.1",
+        },
+        glean.EventsPing{
+            TelemetryFeatureFlags: glean.TelemetryFeatureFlags{
+                FeatureOne:   true,
+                FeatureTwo:   false,
+                FeatureThree: true,
+            },
+        },
+    )
+    """
+
+    logged_output = run_logger(tmp_path, code)
+    logged_output = json.loads(logged_output)
+    fields = logged_output["Fields"]
+    payload_str = fields["payload"]
+    payload = json.loads(payload_str)
+
+    assert "glean-server-event" == logged_output["Type"]
+    assert "glean.test" == fields["document_namespace"]
+    assert "events" == fields["document_type"]
+
+    # Validate payload against Glean schema
+    schema_url = (
+        "https://raw.githubusercontent.com/mozilla-services/"
+        "mozilla-pipeline-schemas/main/"
+        "schemas/glean/glean/glean.1.schema.json"
+    )
+
+    input = io.StringIO(payload_str)
+    output = io.StringIO()
+    assert validate_ping.validate_ping(input, output, schema_url=schema_url) == 0, (
+        output.getvalue()
+    )
+
+    # Check that labeled_boolean is properly serialized as a map
+    labeled_boolean_metrics = payload["metrics"]["labeled_boolean"]
+    assert "telemetry.feature_flags" in labeled_boolean_metrics
+    feature_flags = labeled_boolean_metrics["telemetry.feature_flags"]
+    assert feature_flags["feature_one"] is True
+    assert feature_flags["feature_two"] is False
+    assert feature_flags["feature_three"] is True
+
+
 @pytest.mark.go_dependency
 def test_run_logging_custom_ping_with_event(tmp_path):
     glean_module_path = tmp_path / "glean"