enable lz4 compression for systemd-cat-native when sending messages to a systemd-journal-remote

libnetdata/log/systemd-cat-native.c

@@ -129,6 +129,26 @@ static inline void buffer_memcat_replacing_newlines(BUFFER *wb, const char *src,
 #ifdef HAVE_CURL
 #include <curl/curl.h>
 
+#ifdef ENABLE_LZ4
+#include <lz4.h>
+
+static size_t compress_data_lz4(const char *input, size_t input_size, char **output) {
+    int max_compressed_size = LZ4_compressBound(input_size);
+    *output = malloc(max_compressed_size);
+    if (*output == NULL) {
+        return 0;
+    }
+
+    int compressed_data_size = LZ4_compress_default(input, *output, input_size, max_compressed_size);
+    if (compressed_data_size <= 0) {
+        free(*output);
+        return 0;
+    }
+
+    return compressed_data_size;
+}
+#endif
+
 #ifndef HOST_NAME_MAX
 #define HOST_NAME_MAX 256
 #endif
@@ -170,6 +190,11 @@ CURL* initialize_connection_to_systemd_journal_remote(const char* url, const cha
 
     *headers = curl_slist_append(*headers, "Content-Type: application/vnd.fdo.journal");
     *headers = curl_slist_append(*headers, "Transfer-Encoding: chunked");
+
+#ifdef ENABLE_LZ4
+    *headers = curl_slist_append(*headers, "Content-Encoding: lz4");
+#endif
+
     curl_easy_setopt(curl, CURLOPT_HTTPHEADER, *headers);
     curl_easy_setopt(curl, CURLOPT_URL, url);
     curl_easy_setopt(curl, CURLOPT_POST, 1L);
@@ -211,21 +236,49 @@ static void journal_remote_complete_event(BUFFER *msg, usec_t *monotonic_ut) {
 }
 
 static CURLcode journal_remote_send_buffer(CURL* curl, BUFFER *msg) {
-
     // log_message_to_stderr(msg);
 
-    struct upload_data upload = {0};
-
     if (!curl || !buffer_strlen(msg))
         return CURLE_FAILED_INIT;
 
-    upload.data = (char *) buffer_tostring(msg);
-    upload.length = buffer_strlen(msg);
+    // Original data
+    const char* original_data = buffer_tostring(msg);
+    size_t original_length = buffer_strlen(msg);
+
+#ifdef ENABLE_LZ4
+    // Compress data
+    char* compressed_data = NULL;
+    size_t compressed_length = compress_data_lz4(original_data, original_length, &compressed_data);
+    if (compressed_length == 0 || compressed_data == NULL) {
+        // Handle compression error
+        return CURLE_FAILED_INIT;
+    }
+
+    struct upload_data upload = {
+            .data = compressed_data,
+            .length = compressed_length,
+    };
+
+#else
+    // uncompressed
+
+    struct upload_data upload = {
+            .data = char *)original_data,
+            .length = original_length,
+    };
+#endif
 
     curl_easy_setopt(curl, CURLOPT_READDATA, &upload);
     curl_easy_setopt(curl, CURLOPT_INFILESIZE_LARGE, (curl_off_t)upload.length);
 
-    return curl_easy_perform(curl);
+    CURLcode res = curl_easy_perform(curl);
+
+#ifdef ENABLE_LZ4
+    // Free the compressed data after sending
+    free(compressed_data);
+#endif
+
+    return res;
 }
 
 typedef enum {
@@ -459,6 +512,10 @@ static int help(void) {
             "    This mode is available even when the local system does not support\n"
             "    systemd, or even it is not Linux, allowing a remote Linux systemd\n"
             "    journald to become the logs database of the local system.\n"
+#ifdef ENABLE_LZ4
+            "\n"
+            "    The stream to systemd-journal-remote will be compressed with LZ4\n"
+#endif
             "\n"
             "      --url=URL\n"
             "        The destination systemd-journal-remote address and port, similarly\n"