From 1505118caebd06b186e2fa4b48dbd665c692035a Mon Sep 17 00:00:00 2001
From: Lucas Tembras <lucas.tembras@datadoghq.com>
Date: Fri, 11 Jul 2025 18:32:48 +0000
Subject: [PATCH] out_datadog:  added support for site configuration field

Signed-off-by: Lucas Tembras <lucas.tembras@datadoghq.com>
---
 plugins/out_datadog/datadog.c      |  5 ++-
 plugins/out_datadog/datadog.h      |  1 +
 plugins/out_datadog/datadog_conf.c | 60 +++++++++++++++++++++++++-----
 3 files changed, 56 insertions(+), 10 deletions(-)

diff --git a/plugins/out_datadog/datadog.c b/plugins/out_datadog/datadog.c
index e5c6621f880..e4c12b2f293 100644
--- a/plugins/out_datadog/datadog.c
+++ b/plugins/out_datadog/datadog.c
@@ -581,7 +581,10 @@ static struct flb_config_map config_map[] = {
      0, FLB_TRUE, offsetof(struct flb_out_datadog, json_date_key),
      "Date key name for output."
     },
-
+    {
+    FLB_CONFIG_MAP_STR, "site", NULL, 0, FLB_FALSE, offsetof(struct flb_out_datadog, site),
+    "DataDog site for telemetry data (e.g., 'datadoghq.eu', 'datadoghq.com', 'us3.datadoghq.com'). The plugin will construct the full hostname by prepending 'http-intake.logs.' to this value."
+    },
     /* EOF */
     {0}
 };
diff --git a/plugins/out_datadog/datadog.h b/plugins/out_datadog/datadog.h
index 60e7a676c72..02376ac8029 100644
--- a/plugins/out_datadog/datadog.h
+++ b/plugins/out_datadog/datadog.h
@@ -61,6 +61,7 @@ struct flb_out_datadog {
     flb_sds_t tag_key;
     struct mk_list *headers;
     bool remap;
+    flb_sds_t site;
 
     /* final result */
     flb_sds_t json_date_key;
diff --git a/plugins/out_datadog/datadog_conf.c b/plugins/out_datadog/datadog_conf.c
index a0ef7369df7..2efb60e08a5 100644
--- a/plugins/out_datadog/datadog_conf.c
+++ b/plugins/out_datadog/datadog_conf.c
@@ -40,6 +40,7 @@ struct flb_out_datadog *flb_datadog_conf_create(struct flb_output_instance *ins,
     char *host = NULL;
     char *port = NULL;
     char *uri = NULL;
+    char *site = NULL;
 
     /* Start resource creation */
     ctx = flb_calloc(1, sizeof(struct flb_out_datadog));
@@ -98,6 +99,15 @@ struct flb_out_datadog *flb_datadog_conf_create(struct flb_output_instance *ins,
         return NULL;
     }
 
+    /* Parse site parameter early so it's available for host construction */
+    tmp = flb_output_get_property("site", ins);
+    if (tmp){
+        ctx->site = flb_sds_create(tmp);
+        flb_plg_debug(ctx->ins, "site parameter set to: %s", ctx->site);
+    } else {
+        flb_plg_debug(ctx->ins, "no site parameter found");
+    }
+
     /* Tag Key */
     if (ctx->include_tag_key == FLB_TRUE) {
         ctx->nb_additional_entries++;
@@ -126,7 +136,7 @@ struct flb_out_datadog *flb_datadog_conf_create(struct flb_output_instance *ins,
     tmp = flb_output_get_property("provider", ins);
     ctx->remap = tmp && (strlen(tmp) == strlen(FLB_DATADOG_REMAP_PROVIDER)) && \
         (strncmp(tmp, FLB_DATADOG_REMAP_PROVIDER, strlen(tmp)) == 0);
-
+    
     ctx->uri = flb_sds_create("/api/v2/logs");
     if (!ctx->uri) {
         flb_plg_error(ctx->ins, "error on uri generation");
@@ -138,18 +148,47 @@ struct flb_out_datadog *flb_datadog_conf_create(struct flb_output_instance *ins,
 
     /* Get network configuration */
     if (!ins->host.name) {
-        tmp_sds = flb_sds_create(FLB_DATADOG_DEFAULT_HOST);
+        /* No explicit Host parameter, check for site */
+        if (ctx->site) {
+            flb_plg_debug(ctx->ins, "using site for host construction: %s", ctx->site);
+            /* Construct hostname from site */
+            tmp_sds = flb_sds_create("http-intake.logs.");
+            if (!tmp_sds) {
+                flb_errno();
+                flb_datadog_conf_destroy(ctx);
+                return NULL;
+            }
+            flb_plg_debug(ctx->ins, "created base hostname: %s", tmp_sds);
+            flb_plg_debug(ctx->ins, "about to concatenate site: %s (length: %zu)", ctx->site, flb_sds_len(ctx->site));
+            tmp_sds = flb_sds_cat(tmp_sds, (const char *)ctx->site, flb_sds_len(ctx->site));
+            flb_plg_debug(ctx->ins, "after concatenation: %s", tmp_sds);
+            ctx->host = tmp_sds;
+            flb_plg_debug(ctx->ins, "host constructed from site: %s", ctx->host);
+        } else {
+            flb_plg_debug(ctx->ins, "no site specified, using default host");
+            /* No site specified, use default */
+            tmp_sds = flb_sds_create(FLB_DATADOG_DEFAULT_HOST);
+            if (!tmp_sds) {
+                flb_errno();
+                flb_datadog_conf_destroy(ctx);
+                return NULL;
+            }
+            ctx->host = tmp_sds;
+            flb_plg_debug(ctx->ins, "host: %s", ctx->host);
+        }
     }
     else {
+        flb_plg_debug(ctx->ins, "explicit Host parameter takes precedence: %s", ins->host.name);
+        /* Explicit Host parameter takes precedence */
         tmp_sds = flb_sds_create(ins->host.name);
+        if (!tmp_sds) {
+            flb_errno();
+            flb_datadog_conf_destroy(ctx);
+            return NULL;
+        }
+        ctx->host = tmp_sds;
+        flb_plg_debug(ctx->ins, "host: %s", ctx->host);
     }
-    if (!tmp_sds) {
-        flb_errno();
-        flb_datadog_conf_destroy(ctx);
-        return NULL;
-    }
-    ctx->host = tmp_sds;
-    flb_plg_debug(ctx->ins, "host: %s", ctx->host);
 
     if (ins->host.port != 0) {
         ctx->port = ins->host.port;
@@ -222,6 +261,9 @@ int flb_datadog_conf_destroy(struct flb_out_datadog *ctx)
     if (ctx->upstream) {
         flb_upstream_destroy(ctx->upstream);
     }
+    if (ctx->site){
+        flb_sds_destroy(ctx->site);
+    }
     flb_free(ctx);
 
     return 0;