more work to get prototype working

Signed-off-by: Alex Boten <aboten@lightstep.com>

config.yaml

@@ -144,13 +144,13 @@ sdk:
           # Environment variable: OTEL_TRACES_EXPORTER
           exporter: console
       # Add a batch span processor configured with zipkin exporter. For full description of options see sdk.tracer_provider.span_processors[0].
-      batch/zipkin:
-        args:
-          exporter: zipkin
-      # Add a batch span processor configured with jaeger exporter. For full description of options see sdk.tracer_provider.span_processors[0].
-      batch/jaeger:
-        args:
-          exporter: jaeger
+      # batch/zipkin:
+      #   args:
+      #     exporter: zipkin
+      # # Add a batch span processor configured with jaeger exporter. For full description of options see sdk.tracer_provider.span_processors[0].
+      # batch/jaeger:
+      #   args:
+      #     exporter: jaeger
     # Configure the span limits. See also sdk.attribute_limits.
     span_limits:
       # Set the max span attribute value size. Overrides sdk.attribute_limits.attribute_value_length_limit.

prototypes/python/otel.py

@@ -1,4 +1,5 @@
 
+import importlib
 import logging
 
 import yaml
@@ -8,6 +9,7 @@
 
 from opentelemetry.trace import set_tracer_provider
 
+
 class Config:
     def __init__(self, config=None) -> None:
         self._config = config
@@ -17,14 +19,60 @@ def _resource(self):
         # attributes
         from opentelemetry.sdk.resources import Resource
         return Resource.create(self._config.get("sdk").get("resource").get("attributes"))
+
+    # _get_exporter returns a configured span
+    def _get_exporter(self, signal, name):
+        if name not in self._config.get("sdk").get(signal).get("exporters"):
+            raise Exception(f"exporter {name} not specified for {signal} signal")
 
+        # TODO: replace to use entrypoints
+        _KNOWN_TRACE_EXPORTER_MAP = {
+            "traces": {
+                "console": {
+                    "pkg": "opentelemetry.sdk.trace.export",
+                    "class": "ConsoleSpanExporter",
+                },
+                "jaeger": {
+                    "pkg": "opentelemetry.exporter.jaeger.thrift",
+                    "class": "JaegerExporter",
+                },
+                "zipkin": {
+                    "pkg": "opentelemetry.exporter.zipkin.json",
+                    "class": "ZipkinExporter",
+                },
+            },
+            "metrics": {
+                "console": {
+                    "pkg": "opentelemetry.sdk.metrics.export",
+                    "class": "ConsoleExporter",
+                },
+            },
+            "logs": {
+                "console": {
+                    "pkg": "opentelemetry.sdk.logs.export",
+                    "class": "ConsoleExporter",
+                },
+            }
+        }
+        # look for known exporters
+        if name in _KNOWN_TRACE_EXPORTER_MAP.get(signal):
+            mod = importlib.__import__(_KNOWN_TRACE_EXPORTER_MAP.get(signal).get(name).get("pkg"), fromlist=[_KNOWN_TRACE_EXPORTER_MAP.get(signal).get(name).get("class")])
+            _cls = getattr(mod, _KNOWN_TRACE_EXPORTER_MAP.get(signal).get(name).get("class"))
+            return _cls()
+        # handle case where a custom exporter is used
+
     def set_tracer_provider(self):
         from opentelemetry.sdk.trace import TracerProvider
         provider = TracerProvider(resource=self._resource())
-        from opentelemetry.sdk.trace.export import BatchSpanProcessor, ConsoleSpanExporter
+        from opentelemetry.sdk.trace.export import BatchSpanProcessor
 
-        processor = BatchSpanProcessor(ConsoleSpanExporter())
-        provider.add_span_processor(processor)
+        for processor in self._config.get("sdk").get("traces").get("span_processors"):
+            logging.debug("adding span processor %s", processor)
+            try:
+                processor = BatchSpanProcessor(self._get_exporter("traces", self._config.get("sdk").get("traces").get("span_processors").get(processor).get("args").get("exporter")))
+                provider.add_span_processor(processor)
+            except ModuleNotFoundError as exc:
+                logging.error("module not found", exc)
         set_tracer_provider(provider)
 
     def set_meter_provider(self):
@@ -34,14 +82,15 @@ def apply(self):
         logging.debug("applying configuration %s", self._config)
         if self._config is None or self._config.get("sdk").get("disabled"):
             logging.debug("sdk disabled, nothing to apply")
-            # do nothing
             return
         self.set_tracer_provider()
         self.set_meter_provider()
 
 
 NoOpConfig = Config()
 
+def configure(configuration: Config) -> None:
+    configuration.apply()
 
 def parse_and_validate_from_config_file(filename: str, schema: str="../schema/schema.json") -> Config:
     logging.debug(f"Loading config file: {filename}")

prototypes/python/prototype.py

@@ -5,14 +5,13 @@
 
 from opentelemetry.trace import get_tracer
 
-from otel import parse_and_validate_from_config_file
+import otel
 
 
 
 def main():
     logging.basicConfig(level=logging.DEBUG)
-    config = parse_and_validate_from_config_file(sys.argv[1], sys.argv[2])
-    config.apply()
+    otel.configure(otel.parse_and_validate_from_config_file(sys.argv[1], sys.argv[2]))
 
     tracer = get_tracer("config-prototype")