Merge pull request #49 from exacaster/fix/no_infinite_retry

Do not retry failed session connection forever
exacaster · Jun 15, 2022 · e37ba42 · e37ba42
2 parents 2412b9d + 97c072f
commit e37ba42
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Showing 2 changed files with 30 additions and 16 deletions.
diff --git a/server/src/main/resources/shell_wrapper.py b/server/src/main/resources/shell_wrapper.py
@@ -19,6 +19,17 @@ def setup_output():
     sys.stdout = io.StringIO()
     sys.stderr = io.StringIO()
 
+def _do_with_retry(attempts, action):
+    attempts_left = attempts
+    last_exception = None
+    while attempts_left:
+        try:
+            return action()
+        except Exception as e:
+            last_exception = e
+            attempts_left -= 1
+    raise last_exception
+
 
 class Controller:
     def __init__(self, session_id):
@@ -33,16 +44,18 @@ def write(self, _id, _result):
 
 class TestController(Controller):
     def read(self):
-        try:
+        def do_read():
             str_line = sys_stdin.readline()
             line = json.loads(str_line)
             return [line]
-        except:
-            return []
+        return _do_with_retry(2, do_read)
+
 
     def write(self, id, result):
-        print(json.dumps(result), file=sys_stdout)
-        sys_stdout.flush()
+        def do_write():
+            print(json.dumps(result), file=sys_stdout)
+            sys_stdout.flush()
+        _do_with_retry(2, do_write)
 
 
 class GatewayController(Controller):
@@ -56,17 +69,18 @@ def __init__(self, session_id):
         self.endpoint = self.gateway.entry_point
 
     def read(self):
-        try:
-            return [{"id": stmt.getId(), "code": stmt.getCode()} for stmt in self.endpoint.statementsToProcess(self.session_id)]
-        except Exception as e:
-            log.exception(e)
-            return []
+        return _do_with_retry(
+            3,
+            lambda: [
+              {"id": stmt.getId(), "code": stmt.getCode()} for stmt in self.endpoint.statementsToProcess(self.session_id)
+            ]
+        )
 
     def write(self, id, result):
-        try:
-            self.endpoint.handleResponse(self.session_id, id, result)
-        except Exception as e:
-            log.exception(e)
+        _do_with_retry(
+            3,
+            lambda: self.endpoint.handleResponse(self.session_id, id, result)
+        )
 
 
 class CommandHandler:

diff --git a/...t/groovy/com/exacaster/lighter/application/sessions/processors/PythonProcessorTest.groovy b/...t/groovy/com/exacaster/lighter/application/sessions/processors/PythonProcessorTest.groovy
@@ -1,6 +1,5 @@
 package com.exacaster.lighter.application.sessions.processors
 
-
 import spock.lang.Ignore
 import spock.lang.Specification
 
@@ -12,12 +11,13 @@ class PythonProcessorTest extends Specification {
     def processor
 
     def setup() {
-        def builder = new ProcessBuilder("python3", "/home/paulius/projects/lighter/server/src/main/resources/shell_wrapper.py")
+        def builder = new ProcessBuilder("python3", "./src/main/resources/shell_wrapper.py")
         builder.redirectErrorStream(true)
         def env = builder.environment()
         env.put("PYTHONINSPECT", "true")
         env.put("PYTHONUNBUFFERED", "true")
         env.put("LIGHTER_TEST", "true")
+        env.put("LIGHTER_SESSION_ID", "session1")
         process = builder.start()
         processor = new PythonProcessor(process)
     }