add traces_sampler and parent sampling decision tests

getsentry · Jan 9, 2025 · 17177ec · 17177ec
1 parent 372e887
commit 17177ec
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Showing 2 changed files with 75 additions and 6 deletions.
diff --git a/examples/example.c b/examples/example.c
@@ -426,15 +426,11 @@ main(int argc, char **argv)
         if (has_arg(argc, argv, "unsample-tx")) {
             sentry_transaction_context_set_sampled(tx_ctx, 0);
         }
-        // TODO clean this up to a minimal example (use the rest for tests)
+
         sentry_value_t custom_sampling_ctx = sentry_value_new_object();
-        sentry_value_set_by_key(
-            custom_sampling_ctx, "a", sentry_value_new_string("first_value"));
         sentry_value_set_by_key(
             custom_sampling_ctx, "b", sentry_value_new_int32(42));
-        // sampled parent
-        // sentry_transaction_context_update_from_header(tx_ctx, "sentry-trace",
-        //     "12345678901234567890123456789012-1234567890123456-1");
+
         sentry_transaction_t *tx
             = sentry_transaction_start(tx_ctx, custom_sampling_ctx);
 

diff --git a/tests/unit/test_sampling.c b/tests/unit/test_sampling.c
@@ -1,3 +1,4 @@
+#include "sentry_options.h"
 #include "sentry_sampling_context.h"
 #include "sentry_testsupport.h"
 #include "sentry_tracing.h"
@@ -9,6 +10,25 @@ SENTRY_TEST(sampling_decision)
     TEST_CHECK(sentry__roll_dice(2.0));
 }
 
+static double
+traces_sampler_callback(sentry_sampling_context_t *sampling_ctx)
+{
+    if (!sentry_value_is_null(
+            sentry_sampling_context_get_parent_sampled(sampling_ctx))) {
+        if (sentry_value_is_true(
+                sentry_sampling_context_get_parent_sampled(sampling_ctx))) {
+            return 1; // high sample rate for children of sampled transactions
+        }
+        return 0; // parent is not sampled
+    }
+    if (sentry_value_as_int32(sentry_value_get_by_key(
+            sentry_sampling_context_get_custom_context(sampling_ctx), "answer"))
+        == 42) {
+        return 1;
+    }
+    return 0;
+}
+
 SENTRY_TEST(sampling_transaction)
 {
     sentry_options_t *options = sentry_options_new();
@@ -31,10 +51,63 @@ SENTRY_TEST(sampling_transaction)
     TEST_CHECK(
         sentry__should_send_transaction(tx_cxt->inner, &sampling_ctx) == false);
 
+    // sampled parent -> sampled child
+    sentry_transaction_context_update_from_header(tx_cxt, "sentry-trace",
+        "12345678901234567890123456789012-1234567890123456-1");
+    TEST_CHECK(sentry__should_send_transaction(tx_cxt->inner, &sampling_ctx));
+
+    options = sentry_options_new();
+    sentry_options_set_traces_sample_rate(options, 1.0);
+    TEST_CHECK(sentry_init(options) == 0);
+
+    TEST_CHECK(sentry__should_send_transaction(tx_cxt->inner, &sampling_ctx));
+
+    // non-sampled parent
+    sentry_transaction_context_update_from_header(tx_cxt, "sentry-trace",
+        "12345678901234567890123456789012-1234567890123456-0");
+    TEST_CHECK(
+        sentry__should_send_transaction(tx_cxt->inner, &sampling_ctx) == false);
+
+    sentry_transaction_context_remove_sampled(tx_cxt);
+
+    // test the traces_sampler callback
     options = sentry_options_new();
+    sentry_options_set_traces_sampler(options, traces_sampler_callback);
     sentry_options_set_traces_sample_rate(options, 1.0);
     TEST_CHECK(sentry_init(options) == 0);
 
+    sentry_value_t custom_sampling_ctx = sentry_value_new_object();
+    sentry_value_set_by_key(
+        custom_sampling_ctx, "answer", sentry_value_new_int32(42));
+    sampling_ctx.custom_sampling_context = custom_sampling_ctx;
+
+    TEST_CHECK(sentry__should_send_transaction(tx_cxt->inner, &sampling_ctx));
+
+    // non-sampled parent and traces sampler
+    sentry_transaction_context_update_from_header(tx_cxt, "sentry-trace",
+        "12345678901234567890123456789012-1234567890123456-0");
+    TEST_CHECK(
+        sentry__should_send_transaction(tx_cxt->inner, &sampling_ctx) == false);
+    // removing sampled should fall back to traces sampler
+    sentry_transaction_context_remove_sampled(tx_cxt);
+    TEST_CHECK(sentry__should_send_transaction(tx_cxt->inner, &sampling_ctx));
+    sentry_value_set_by_key(
+        custom_sampling_ctx, "answer", sentry_value_new_int32(21));
+    TEST_CHECK(
+        sentry__should_send_transaction(tx_cxt->inner, &sampling_ctx) == false);
+
+    // sampled parent and traces sampler
+    sentry_transaction_context_update_from_header(tx_cxt, "sentry-trace",
+        "12345678901234567890123456789012-1234567890123456-1");
+    TEST_CHECK(sentry__should_send_transaction(tx_cxt->inner, &sampling_ctx));
+    sentry_transaction_context_remove_sampled(tx_cxt);
+
+    // remove traces_sampler callback, should fall back to traces_sample_rate
+    options->traces_sampler = NULL;
+    sentry_options_set_traces_sample_rate(options, 0.0);
+    TEST_CHECK(
+        sentry__should_send_transaction(tx_cxt->inner, &sampling_ctx) == false);
+    sentry_options_set_traces_sample_rate(options, 1.0);
     TEST_CHECK(sentry__should_send_transaction(tx_cxt->inner, &sampling_ctx));
 
     sentry__transaction_context_free(tx_cxt);