feat(data-pipeline): encode structured values

examples/ffi/trace_exporter.c

@@ -81,8 +81,81 @@ int test_error_on_panic(void) {
     return 0;
 }
 
+int verify_structured_value_encoder(void) {
+    uint8_t text[] = "stable";
+    uint8_t binary[] = {0x00, 0xff};
+    ddog_TracerValueToken tokens[] = {
+        {.kind = DDOG_TRACER_VALUE_ARRAY, .child_count = 2},
+        {
+            .kind = DDOG_TRACER_VALUE_STRING,
+            .bytes = {.ptr = text, .len = sizeof(text) - 1},
+        },
+        {
+            .kind = DDOG_TRACER_VALUE_BINARY,
+            .bytes = {.ptr = binary, .len = sizeof(binary)},
+        },
+    };
+    ddog_TracerEncodedValue *blob = NULL;
+    ddog_TraceExporterError *err = ddog_tracer_encode_value(
+        (ddog_Slice_TracerValueToken){
+            .ptr = tokens,
+            .len = sizeof(tokens) / sizeof(tokens[0]),
+        },
+        &blob);
+    if (err) {
+        handle_error(err);
+        return 1;
+    }
+
+    memset(text, 'x', sizeof(text) - 1);
+    memset(binary, 'x', sizeof(binary));
+    static const uint8_t expected[] = {
+        0x92, 0xa6, 's','t','a','b','l','e', 0xc4, 0x02, 0x00, 0xff,
+    };
+    ddog_ByteSlice encoded = ddog_tracer_encoded_value_as_slice(blob);
+    int matches = encoded.len == sizeof(expected) &&
+        memcmp(encoded.ptr, expected, sizeof(expected)) == 0;
+    ddog_tracer_encoded_value_free(blob);
+    if (!matches) {
+        fprintf(stderr, "Structured value encoder did not return an owned blob\n");
+        return 1;
+    }
+    return 0;
+}
+
+int verify_structured_value_encoder_rejects_invalid(void) {
+    ddog_TracerValueToken tokens[] = {
+        {.kind = 255},
+    };
+    ddog_TracerEncodedValue *blob = NULL;
+    ddog_TraceExporterError *err = ddog_tracer_encode_value(
+        (ddog_Slice_TracerValueToken){
+            .ptr = tokens,
+            .len = sizeof(tokens) / sizeof(tokens[0]),
+        },
+        &blob);
+    if (err == NULL) {
+        fprintf(stderr, "Structured value encoder accepted an unknown token kind\n");
+        ddog_tracer_encoded_value_free(blob);
+        return 1;
+    }
+    ddog_trace_exporter_error_free(err);
+
+    // The encoder writes the out-handle only on success, so a rejected input
+    // leaves the caller's NULL blob untouched and there is nothing to free.
+    if (blob != NULL) {
+        fprintf(stderr, "Structured value encoder wrote a blob on the error path\n");
+        ddog_tracer_encoded_value_free(blob);
+        return 1;
+    }
+    return 0;
+}
+
 int main(int argc, char** argv)
 {
+    if (verify_structured_value_encoder() != 0) return 1;
+    if (verify_structured_value_encoder_rejects_invalid() != 0) return 1;
+
     // Initialize logger with optional path from command line
     const char* log_path = (argc > 1) ? argv[1] : NULL;
     if (log_init(log_path) != 0) {

libdd-data-pipeline-ffi/Cargo.toml

@@ -38,5 +38,6 @@ libdd-shared-runtime = { version = "2.0.0", path = "../libdd-shared-runtime" }
 libdd-common-ffi = { path = "../libdd-common-ffi", default-features = false }
 libdd-tinybytes = { path = "../libdd-tinybytes" }
 libdd-trace-utils = { path = "../libdd-trace-utils" }
+rmp = { version = "0.8.14", default-features = false }
 tokio-util = "0.7.11"
 tracing.workspace = true

libdd-data-pipeline-ffi/cbindgen.toml

@@ -15,6 +15,7 @@ typedef struct ddog_TracerSpan ddog_TracerSpan;
 typedef struct ddog_TracerSpanEvent ddog_TracerSpanEvent;
 typedef struct ddog_TracerTraceChunks ddog_TracerTraceChunks;
 typedef struct ddog_TraceExporterCancelToken ddog_TraceExporterCancelToken;
+typedef uint8_t ddog_TracerValueKind;
 """
 
 [export]
@@ -38,6 +39,15 @@ exclude = ["TraceExporter", "TracerSpan", "TracerSpanEvent", "TracerTraceChunks"
 "TracerSpanLinkAttribute" = "ddog_TracerSpanLinkAttribute"
 "TracerTraceChunks" = "ddog_TracerTraceChunks"
 "TokioCancellationToken" = "ddog_TraceExporterCancelToken"
+"DDOG_TRACER_VALUE_NIL" = "DDOG_TRACER_VALUE_NIL"
+"DDOG_TRACER_VALUE_BOOL" = "DDOG_TRACER_VALUE_BOOL"
+"DDOG_TRACER_VALUE_I64" = "DDOG_TRACER_VALUE_I64"
+"DDOG_TRACER_VALUE_U64" = "DDOG_TRACER_VALUE_U64"
+"DDOG_TRACER_VALUE_F64" = "DDOG_TRACER_VALUE_F64"
+"DDOG_TRACER_VALUE_STRING" = "DDOG_TRACER_VALUE_STRING"
+"DDOG_TRACER_VALUE_BINARY" = "DDOG_TRACER_VALUE_BINARY"
+"DDOG_TRACER_VALUE_ARRAY" = "DDOG_TRACER_VALUE_ARRAY"
+"DDOG_TRACER_VALUE_MAP" = "DDOG_TRACER_VALUE_MAP"
 
 [export.mangle]
 rename_types = "PascalCase"

libdd-data-pipeline-ffi/src/lib.rs

@@ -8,6 +8,7 @@
 
 mod error;
 mod response;
+mod structured_value;
 mod trace_exporter;
 mod tracer;