From c19b0d08be3ce70641c1c5707d3e67fa3c50c72e Mon Sep 17 00:00:00 2001
From: chenzizhan <chenzizhan@geedgenetworks.com>
Date: Mon, 18 Dec 2023 10:36:10 +0800
Subject: feat: fieldstat easy reset

---
 include/fieldstat/fieldstat_easy.h |  4 ++++
 src/fieldstat_easy.c               | 29 ++++++++++++++++++++++++++---
 test/test_easy_fs.cpp              | 17 +++++++++++++++++
 3 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/include/fieldstat/fieldstat_easy.h b/include/fieldstat/fieldstat_easy.h
index b222644..8b12780 100644
--- a/include/fieldstat/fieldstat_easy.h
+++ b/include/fieldstat/fieldstat_easy.h
@@ -20,6 +20,10 @@ struct fieldstat_easy *fieldstat_easy_new(int max_thread_num, const char *name,
     * free a fieldstat_easy instance.
 */
 void fieldstat_easy_free(struct fieldstat_easy *fse);
+/*
+    * reset the instance. Will fail and return -1 if fieldstat_easy_enable_auto_output is called, since the behavior is hard to define.
+*/
+int fieldstat_easy_reset(struct fieldstat_easy *fse);
 /*
     * enable auto output. both data of accumulated and delta will be output.
     * @param output_path: output file path. Should be identical to the one in python config.
diff --git a/src/fieldstat_easy.c b/src/fieldstat_easy.c
index 61f17c5..a3fc148 100644
--- a/src/fieldstat_easy.c
+++ b/src/fieldstat_easy.c
@@ -256,9 +256,11 @@ struct fieldstat *merge_all_instance(struct fieldstat_easy *fse)
     }
 
     // add the outputted data
-    pthread_spin_lock(&fse->outputting_lock);
-    fieldstat_merge(dst, fse->accumulate);
-    pthread_spin_unlock(&fse->outputting_lock);
+    if (fse->output_thread_running) {
+        pthread_spin_lock(&fse->outputting_lock);
+        fieldstat_merge(dst, fse->accumulate);
+        pthread_spin_unlock(&fse->outputting_lock);
+    }
 
     return dst;
 }
@@ -318,3 +320,24 @@ int fieldstat_easy_histogram_record(struct fieldstat_easy *fse, int thread_id, i
 
     return ret;
 }
+
+int fieldstat_easy_reset(struct fieldstat_easy *fse)
+{
+    // We can't let the user reset operation affects auto passive output, just let it fail.
+    if (fse->output_thread_running) {
+        printf("fieldstat_easy_reset: reset is not allowed when auto output is enabled.\n");
+        return -1;
+    }
+
+    for (int i = 0; i < fse->max_thread_num; i++) {
+        pthread_spin_lock(&fse->fsu[i].lock);
+        fieldstat_reset(fse->fsu[i].active);
+        // fsu.read_only: Only for output_to_file.
+        pthread_spin_unlock(&fse->fsu[i].lock);
+    }
+
+    // accumulate: Only has data when output_to_file.
+    // delta: Only for output_to_file.
+
+    return 0;
+}
\ No newline at end of file
diff --git a/test/test_easy_fs.cpp b/test/test_easy_fs.cpp
index 54e22f6..d6f9177 100644
--- a/test/test_easy_fs.cpp
+++ b/test/test_easy_fs.cpp
@@ -199,6 +199,23 @@ TEST(test_easy_fieldstat, ensure_data_racing_of_two_output_and_of_incyby)
     remove(FILENAME);
 }
 
+TEST(test_easy_fieldstat, reset)
+{
+    struct fieldstat_easy *fse = fieldstat_easy_new(3, NULL, NULL, 0);
+    int counter_id = fieldstat_easy_register_counter(fse, "metric counter");
+    fieldstat_easy_counter_incrby(fse, 0, counter_id, &TEST_TAG_INT, 1, 1);
+    fieldstat_easy_counter_incrby(fse, 1, counter_id, &TEST_TAG_INT, 1, 1);
+    
+    fieldstat_easy_reset(fse);
+    char *buff = NULL;
+    size_t buff_len = 0;
+    fieldstat_easy_output(fse, &buff, &buff_len);
+    EXPECT_STREQ(buff, "[]");
+
+    free(buff);
+    fieldstat_easy_free(fse);
+}
+
 int main(int argc, char **argv)
 {
     ::testing::InitGoogleTest(&argc, argv);
-- 
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