truncate the output file

Author: anarthal

tools/ci/ci_util/bench.py

@@ -11,12 +11,16 @@
 from pathlib import Path
 from subprocess import check_output
 
+_results_file = 'benchmark-results.txt'
+
+
 def _record_measurement(bench: str, time: int) -> None:
     print('{}: {}ms'.format(bench, time), flush=True)
-    with open('benchmark-results.txt', 'at') as f:
-        f.write('{},{}'.format(bench, time))
+    with open(_results_file, 'at') as f:
+        f.write('{},{}\n'.format(bench, time))
 
-def run_connection_pool_bench(
+
+def _run_connection_pool(
     exe_dir: Path,
     iters: int,
     server_host: str,
@@ -39,7 +43,7 @@ def run_connection_pool_bench(
             _record_measurement(bench, time)
 
 
-def run_protocol_bench(
+def _run_protocol(
     exe_dir: Path,
     iters: int,
 ) -> None:
@@ -62,3 +66,17 @@ def run_protocol_bench(
             time = int(check_output([exe]).decode())
             _record_measurement(bench, time)
 
+
+def run_benchmarks(
+    exe_dir: Path,
+    server_host: str,
+    connection_pool_iters: int,
+    protocol_iters: int,
+) -> None:
+    # Truncate the results file, if it exists
+    with open(_results_file, 'wt') as f:
+        pass
+
+    # Run the benchmarks
+    _run_connection_pool(exe_dir, connection_pool_iters, server_host)
+    _run_protocol(exe_dir, protocol_iters)

tools/ci/ci_util/cmake.py

@@ -12,7 +12,7 @@
 from .common import run, BOOST_ROOT, IS_WINDOWS, mkdir_and_cd
 from .db_setup import db_setup, db_setup_bench
 from .install_boost import install_boost
-from .bench import run_connection_pool_bench, run_protocol_bench
+from .bench import run_benchmarks
 
 
 def _cmake_prefix_path(extra_path: Optional[Path] = None) -> str:
@@ -284,6 +284,9 @@ def bench_build(
     runner.build(target='boost_mysql_bench')
 
     # Run the benchmarks
-    exe_dir = bin_dir.joinpath('stage', 'bin')
-    run_connection_pool_bench(exe_dir, connection_pool_iters, server_host)
-    run_protocol_bench(exe_dir, protocol_iters)
+    run_benchmarks(
+        exe_dir=bin_dir.joinpath('stage', 'bin'),
+        server_host=server_host,
+        connection_pool_iters=connection_pool_iters,
+        protocol_iters=protocol_iters,
+    )