Histogram smoketests (#39)

4 files changed, 218 insertions, 0 deletions

diff --git a/promtest/CMakeLists.txt b/promtest/CMakeLists.txt
index 3c6de45..fa5d8b2 100644
--- a/promtest/CMakeLists.txt
+++ b/promtest/CMakeLists.txt
@@ -112,6 +112,8 @@ add_executable(
     ${test_dir}/promtest_counter.h
     ${test_dir}/promtest_gauge.c
     ${test_dir}/promtest_gauge.h
+    ${test_dir}/promtest_histogram.c
+    ${test_dir}/promtest_histogram.h
 )
 target_link_libraries(promtest microhttpd prom promhttp Unity parson Threads::Threads)
 target_include_directories(promtest PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/src)
diff --git a/promtest/test/promtest.c b/promtest/test/promtest.c
index 4c7721b..5f1939e 100644
--- a/promtest/test/promtest.c
+++ b/promtest/test/promtest.c
@@ -16,6 +16,7 @@
 
 #include "promtest_counter.h"
 #include "promtest_gauge.h"
+#include "promtest_histogram.h"
 #include "promtest_helpers.h"
 #include "unity.h"
 
@@ -23,5 +24,6 @@ int main(int argc, const char **argv) {
   UNITY_BEGIN();
   RUN_TEST(promtest_counter);
   RUN_TEST(promtest_gauge);
+  RUN_TEST(promtest_histogram);
   return UNITY_END();
 }
diff --git a/promtest/test/promtest_histogram.c b/promtest/test/promtest_histogram.c
new file mode 100644
index 0000000..ac8fd00
--- /dev/null
+++ b/promtest/test/promtest_histogram.c
@@ -0,0 +1,185 @@
+/**
+ * Copyright 2019-2020 DigitalOcean Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "promtest_histogram.h"
+
+#include <pthread.h>
+
+#include "parson.h"
+#include "prom.h"
+#include "promhttp.h"
+#include "promtest_helpers.h"
+#include "unity.h"
+
+static void *promtest_histogram_handler(void *data);
+static int promtest_parse_histogram_output(const char *output, char **value);
+prom_histogram_t *foo_histogram;
+
+/**
+ * @brief For each thread in a threadpool of 10 we increment a single histogram 1
+ * million times
+ *
+ * The purpose of this test is to check for deadlock and race conditions
+ */
+void promtest_histogram(void) {
+  if (promtest_histogram_setup()) {
+    TEST_FAIL_MESSAGE("failed to setup promtest_histogram");
+  }
+
+  void *retvals[PROMTEST_THREAD_POOL_SIZE];
+  pthread_t thread_pool[PROMTEST_THREAD_POOL_SIZE];
+
+  // Start each thread
+  for (int i = 0; i < PROMTEST_THREAD_POOL_SIZE; i++) {
+    if (pthread_create(&(thread_pool[i]), NULL, promtest_histogram_handler, NULL)) {
+      TEST_FAIL_MESSAGE("failed to create thread");
+    }
+  }
+
+  // Join each thread
+  for (int i = 0; i < PROMTEST_THREAD_POOL_SIZE; i++) {
+    if (pthread_join(thread_pool[i], (void **)&(retvals[i]))) {
+      TEST_FAIL_MESSAGE("thread failed to join");
+    }
+  }
+
+  // verify clean exit for each thread
+  for (int i = 0; i < PROMTEST_THREAD_POOL_SIZE; i++) {
+    if (*((int *)retvals[i]) != 0) {
+      TEST_FAIL_MESSAGE("thread did not exit properly");
+    }
+  }
+
+  // scrape the endpoint
+  FILE *f = popen("prom2json http://0.0.0.0:8000/metrics", "r");
+  if (f == NULL) {
+    TEST_FAIL_MESSAGE("shell out failed");
+  }
+  promtest_popen_buf_t *buf = promtest_popen_buf_new(f);
+  if (promtest_popen_buf_read(buf)) {
+    TEST_FAIL_MESSAGE("failed to scrape endpoint");
+  }
+
+  const char *output = strdup(buf->buf);
+  if (promtest_popen_buf_destroy(buf)) {
+    TEST_FAIL_MESSAGE("failed to duplicate buf");
+  }
+
+  // Parse the output
+  char *value = (char *)malloc(sizeof(char) * 100);
+  if (promtest_parse_histogram_output(output, &value)) {
+    TEST_FAIL_MESSAGE("failed to parse output");
+  }
+
+  // Assert
+  //TEST_ASSERT_EQUAL_STRING("5e+06", value);
+  TEST_ASSERT_EQUAL_STRING("5000000", value);
+  if (promtest_histogram_teardown()) {
+    TEST_FAIL_MESSAGE("failed to teardown promtest_histogram");
+  }
+
+  free(value);
+}
+
+int promtest_histogram_setup(void) {
+  // Initialize the default collector registry
+  prom_collector_registry_default_init();
+
+  // Set the histogram
+  foo_histogram =
+      prom_collector_registry_must_register_metric(prom_histogram_new("foo_histogram", "histogram for foo", prom_histogram_default_buckets, 0, NULL));
+
+  // Set the collector registry on the handler to the default registry
+  promhttp_set_active_collector_registry(NULL);
+
+  // Start the HTTP server
+  promtest_daemon = promhttp_start_daemon(MHD_USE_SELECT_INTERNALLY, 8000, NULL, NULL);
+
+  if (promtest_daemon == NULL)
+    return 1;
+  else
+    return 0;
+}
+
+int promtest_histogram_teardown(void) {
+  // Destroy the default registry. This effectively deallocates all metrics
+  // registered to it, including itself
+  prom_collector_registry_destroy(PROM_COLLECTOR_REGISTRY_DEFAULT);
+  PROM_COLLECTOR_REGISTRY_DEFAULT = NULL;
+
+  // Stop the HTTP server
+  MHD_stop_daemon(promtest_daemon);
+
+  return 0;
+}
+
+/**
+ * @brief The entrypoint to a worker thread within the prom_histogram_test
+ */
+static void *promtest_histogram_handler(void *data) {
+  for (int i = 0; i < 1000000; i++) {
+    prom_histogram_observe(foo_histogram, i/1000.0, NULL);
+  }
+  int *retval = (int *)malloc(sizeof(int));
+  *retval = 0;
+  return (void *)retval;
+}
+
+/**
+ * @brief Parse the output and set the value of the foo_histogram metric.
+ *
+ * We must past a pointer to a char* so the value gets updated
+ */
+static int promtest_parse_histogram_output(const char *output, char **value) {
+  // Parse the JSON output
+  JSON_Value *root = json_parse_string(output);
+  if (json_value_get_type(root) != JSONArray) {
+    TEST_FAIL_MESSAGE("JSON Parse error...expected JSONArray type");
+  }
+
+  JSON_Array *collection = json_value_get_array(root);
+  if (collection == NULL) {
+    TEST_FAIL_MESSAGE("Failed to extract array from JSON_Value");
+  }
+
+  for (int i = 0; i < json_array_get_count(collection); i++) {
+    JSON_Object *obj = json_array_get_object(collection, i);
+    if (obj == NULL) {
+      TEST_FAIL_MESSAGE("failed to retrieve single object within JSON_Array");
+    }
+    const char *name = json_object_get_string(obj, "name");
+    if (strcmp(name, "foo_histogram")) {
+      continue;
+    }
+    JSON_Array *samples = json_object_dotget_array(obj, "metrics");
+    if (samples == NULL) {
+      TEST_FAIL_MESSAGE("failed to retrieve metrics from JSON_Object");
+    }
+    if (json_array_get_count(samples) < 1) {
+      TEST_FAIL_MESSAGE("No samples found");
+    }
+    JSON_Object *sample = json_array_get_object(samples, 0);
+    if (sample == NULL) {
+      TEST_FAIL_MESSAGE("failed to get metric sample");
+    }
+    *value = (char *)json_object_get_string(sample, "count");
+    break;
+  }
+  if (strlen(*value) == 0) {
+    return 1;
+  }
+  return 0;
+}
diff --git a/promtest/test/promtest_histogram.h b/promtest/test/promtest_histogram.h
new file mode 100644
index 0000000..de4ef67
--- /dev/null
+++ b/promtest/test/promtest_histogram.h
@@ -0,0 +1,29 @@
+/**
+ * Copyright 2019-2020 DigitalOcean Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "prom.h"
+
+#ifndef PROMTEST_HISTOGRAM_H
+#define PROMTEST_HISTOGRAM_H
+
+extern prom_histogram_t *foo_histogram;
+
+int promtest_histogram_setup(void);
+int promtest_histogram_teardown(void);
+
+void promtest_histogram(void);
+
+#endif  // PROMTEST_HISTOGRAM_H