Expose Core console log format

CHANGELOG.md

@@ -20,6 +20,9 @@ to include examples, links to docs, or any other relevant information.
 
 ### Added
 
+- Added `LoggingConfig.format` to select compact, pretty, or newline-delimited JSON output for
+  Core logs written to the console.
+
 - Added the `Runtime(disable_environment_info=...)` option to control whether
   runtime, hosting, and platform information is included in worker heartbeats.
 

temporalio/bridge/runtime.py

@@ -47,6 +47,7 @@ class LoggingConfig:
 
     filter: str
     forward_to: Callable[[Sequence[BufferedLogEntry]], None] | None
+    format: str | None
 
 
 @dataclass(frozen=True)

temporalio/bridge/src/runtime.rs

@@ -13,8 +13,8 @@ use temporalio_common::telemetry::metrics::core::MetricCallBufferer;
 use temporalio_common::telemetry::metrics::CoreMeter;
 use temporalio_common::telemetry::{
     build_otlp_metric_exporter, start_prometheus_metric_exporter, CoreLog, CoreLogStreamConsumer,
-    Logger, MetricTemporality, OtelCollectorOptions, OtlpProtocol, PrometheusExporterOptions,
-    TelemetryOptions,
+    Logger, LoggerFormat, MetricTemporality, OtelCollectorOptions, OtlpProtocol,
+    PrometheusExporterOptions, TelemetryOptions,
 };
 use temporalio_sdk_core::telemetry::MetricsCallBuffer;
 use temporalio_sdk_core::{CoreRuntime, TokioRuntimeBuilder};
@@ -48,6 +48,7 @@ pub struct TelemetryConfig {
 pub struct LoggingConfig {
     filter: String,
     forward_to: Option<Py<PyAny>>,
+    format: Option<String>,
 }
 
 #[pyclass]
@@ -121,6 +122,15 @@ pub fn init_runtime(options: RuntimeOptions) -> PyResult<RuntimeRef> {
         } else {
             Logger::Console {
                 filter: logging_conf.filter.to_string(),
+                format: logging_conf
+                    .format
+                    .map(|format| match format.as_str() {
+                        "compact" => Ok(LoggerFormat::Compact),
+                        "pretty" => Ok(LoggerFormat::Pretty),
+                        "json" => Ok(LoggerFormat::Json),
+                        _ => Err(PyValueError::new_err("Unrecognized logging format")),
+                    })
+                    .transpose()?,
             }
         })
     } else {

temporalio/runtime.py

@@ -195,6 +195,14 @@ def formatted(self) -> str:
         return ",".join(parts)
 
 
+class LoggingFormat(Enum):
+    """Format for Core logs written to the console."""
+
+    COMPACT = "compact"
+    PRETTY = "pretty"
+    JSON = "json"
+
+
 @dataclass(frozen=True)
 class LoggingConfig:
     """Configuration for runtime logging."""
@@ -207,6 +215,12 @@ class LoggingConfig:
     See the :py:class:`LogForwardingConfig` docs for more info.
     """
 
+    format: LoggingFormat | None = None
+    """Format for Core logs written to the console. This is ignored when
+    :py:attr:`forwarding` is set. If unset, Core preserves its existing output
+    selection, including ``TEMPORAL_CORE_PRETTY_LOGS`` support.
+    """
+
     default: ClassVar[LoggingConfig]
     """Default logging configuration of Core WARN level and other ERROR
     level.
@@ -218,6 +232,7 @@ def _to_bridge_config(self) -> temporalio.bridge.runtime.LoggingConfig:
             if isinstance(self.filter, str)
             else self.filter.formatted(),
             forward_to=None if not self.forwarding else self.forwarding._on_logs,
+            format=None if not self.format else self.format.value,
         )
 
 

tests/test_runtime.py

@@ -16,6 +16,7 @@
 from temporalio.runtime import (
     LogForwardingConfig,
     LoggingConfig,
+    LoggingFormat,
     OpenTelemetryConfig,
     PrometheusConfig,
     Runtime,
@@ -143,6 +144,11 @@ async def log_queue_len() -> int:
         )
 
 
+def test_runtime_console_logging_format():
+    config = LoggingConfig(filter="INFO", format=LoggingFormat.JSON)._to_bridge_config()
+    assert config.format == "json"
+
+
 @workflow.defn
 class TaskFailWorkflow:
     @workflow.run