From a7d106bc92b233b342ba81954d2f4d840389452c Mon Sep 17 00:00:00 2001
From: Florian Bezannier <florian.bezannier@hotmail.fr>
Date: Tue, 18 Oct 2022 15:05:00 +0200
Subject: [PATCH] out_opentelemetry: add gzip compression

---
 build/.empty                                  |  0
 plugins/out_opentelemetry/opentelemetry.c     | 28 +++++++++++++++++--
 plugins/out_opentelemetry/opentelemetry.h     |  3 ++
 .../out_opentelemetry/opentelemetry_conf.c    |  9 ++++++
 4 files changed, 37 insertions(+), 3 deletions(-)
 delete mode 100644 build/.empty

diff --git a/build/.empty b/build/.empty
deleted file mode 100644
index e69de29bb2d..00000000000
diff --git a/plugins/out_opentelemetry/opentelemetry.c b/plugins/out_opentelemetry/opentelemetry.c
index bfeceddac1c..738be674176 100644
--- a/plugins/out_opentelemetry/opentelemetry.c
+++ b/plugins/out_opentelemetry/opentelemetry.c
@@ -28,6 +28,7 @@
 #include <fluent-otel-proto/fluent-otel.h>
 
 #include <cmetrics/cmetrics.h>
+#include <fluent-bit/flb_gzip.h>
 #include <cmetrics/cmt_encode_opentelemetry.h>
 
 #include <ctraces/ctraces.h>
@@ -55,6 +56,9 @@ static int http_post(struct opentelemetry_context *ctx,
     struct flb_config_map_val *mv;
     struct flb_slist_entry *key = NULL;
     struct flb_slist_entry *val = NULL;
+    void *final_body = NULL;
+    size_t final_body_len = 0;
+    int compressed = FLB_FALSE;
 
     /* Get upstream context and connection */
     u = ctx->u;
@@ -64,10 +68,21 @@ static int http_post(struct opentelemetry_context *ctx,
                       u->tcp_host, u->tcp_port);
         return FLB_RETRY;
     }
-
+     if (ctx->compress_gzip == FLB_TRUE) {
+        ret = flb_gzip_compress((void *) body, body_len,
+                                &final_body, &final_body_len);
+        if (ret == -1) {
+            flb_plg_error(ctx->ins, "cannot gzip payload, disabling compression");
+        } else {
+            compressed = FLB_TRUE;
+        }
+    } else {
+        final_body = body;
+        final_body_len = body_len;
+    }
     /* Create HTTP client context */
     c = flb_http_client(u_conn, FLB_HTTP_POST, uri,
-                        body, body_len,
+                        final_body, final_body_len,
                         ctx->host, ctx->port,
                         ctx->proxy, 0);
 
@@ -107,7 +122,9 @@ static int http_post(struct opentelemetry_context *ctx,
                             key->str, flb_sds_len(key->str),
                             val->str, flb_sds_len(val->str));
     }
-
+    if (compressed == FLB_TRUE) {
+        flb_http_set_content_encoding_gzip(c);
+    }
     ret = flb_http_do(c, &b_sent);
     if (ret == 0) {
         /*
@@ -606,6 +623,11 @@ static struct flb_config_map config_map[] = {
      0, FLB_TRUE, offsetof(struct opentelemetry_context, log_response_payload),
      "Specify if the response paylod should be logged or not"
     },
+    {
+     FLB_CONFIG_MAP_STR, "compress", NULL,
+     0, FLB_FALSE, 0,
+     "Set payload compression mechanism. Option available is 'gzip'"
+    },
     /* EOF */
     {0}
 };
diff --git a/plugins/out_opentelemetry/opentelemetry.h b/plugins/out_opentelemetry/opentelemetry.h
index 81693bb5e65..2c177145b96 100644
--- a/plugins/out_opentelemetry/opentelemetry.h
+++ b/plugins/out_opentelemetry/opentelemetry.h
@@ -62,6 +62,9 @@ struct opentelemetry_context {
 
     /* instance context */
     struct flb_output_instance *ins;
+
+    /* Compression mode (gzip) */
+    int compress_gzip;
 };
 
 #endif
diff --git a/plugins/out_opentelemetry/opentelemetry_conf.c b/plugins/out_opentelemetry/opentelemetry_conf.c
index ff928b60622..060f9f94bec 100644
--- a/plugins/out_opentelemetry/opentelemetry_conf.c
+++ b/plugins/out_opentelemetry/opentelemetry_conf.c
@@ -141,6 +141,7 @@ struct opentelemetry_context *flb_opentelemetry_context_create(
     char *logs_uri = NULL;
     struct flb_upstream *upstream;
     struct opentelemetry_context *ctx = NULL;
+    char *tmp = NULL;
 
     /* Allocate plugin context */
     ctx = flb_calloc(1, sizeof(struct opentelemetry_context));
@@ -214,6 +215,14 @@ struct opentelemetry_context *flb_opentelemetry_context_create(
     /* Set instance flags into upstream */
     flb_output_upstream_set(ctx->u, ins);
 
+    tmp = flb_output_get_property("compress", ins);
+    ctx->compress_gzip = FLB_FALSE;
+    if (tmp) {
+        if (strcasecmp(tmp, "gzip") == 0) {
+            ctx->compress_gzip = FLB_TRUE;
+        }
+    }
+
     return ctx;
 }