Add a GUC to log HTTP requests

Especially useful for #68

Author: sfc-gh-okalaci

pg_lake_iceberg/include/pg_lake/http/http_client.h

@@ -34,6 +34,8 @@ typedef struct
 	const char *errorMsg;		/* error message */
 }			HttpResult;
 
+extern bool HttpClientTraceTraffic;
+
 /* plain C API (no PostgreSQL types) */
 extern PGDLLEXPORT HttpResult HttpGet(const char *url, List *headers);
 extern PGDLLEXPORT HttpResult HttpHead(const char *url, List *headers);

pg_lake_iceberg/src/http/http_client.c

@@ -70,6 +70,7 @@ static void CurlGlobalCleanup(int code, Datum arg);
 static void CurlCleanup(CURL * curl, struct curl_slist *headerList);
 static HttpResult CurlReturnError(CURL * curl, struct curl_slist *headerList,
 								  CURLcode curlCode, const char *errorMsg);
+static const char * HttpRequestMethodToString(HttpMethod method);
 
 #define CURL_SETOPT(curl, opt, value) do { \
 	curlCode = curl_easy_setopt((curl), (opt), (value)); \
@@ -82,6 +83,9 @@ static HttpResult CurlReturnError(CURL * curl, struct curl_slist *headerList,
 static bool curlInitialized = false;
 
 
+bool		HttpClientTraceTraffic = false;
+
+
 /*
  * CurlGloballyInitIfNotInitialized globally initiates curl state if not initialized.
  */
@@ -447,6 +451,21 @@ HttpCommonNoThrows(HttpMethod method, const char *url, const char *postData, con
 	struct curl_slist *curlHeaders = NULL;
 	CURLcode	curlCode = CURLE_OK;
 
+	if (HttpClientTraceTraffic && message_level_is_interesting(INFO))
+	{
+		StringInfo postDataInfo = NULL;
+
+		if (postData)
+		{
+			postDataInfo = makeStringInfo();
+			appendStringInfo(postDataInfo, " : {%s}", postData);
+		}
+
+		ereport(INFO, (errmsg("making %s request to URL %s%s",
+					   HttpRequestMethodToString(method), url, 
+					   postDataInfo ? postDataInfo->data : "")));
+	}
+
 	if (!CheckMinCurlVersion(curl_version_info(CURLVERSION_NOW)))
 		return CurlReturnError(curl, curlHeaders, CURLE_FAILED_INIT, "pg_lake_iceberg requires Curl version 7.20.0 or higher");
 
@@ -508,5 +527,32 @@ HttpCommonNoThrows(HttpMethod method, const char *url, const char *postData, con
 
 	ereport(DEBUG4, (errmsg("libcurl request completed successfully")));
 
+	if (HttpClientTraceTraffic && message_level_is_interesting(INFO))
+	{
+		ereport(INFO, (errmsg("received response with status code %ld, body: %s", 
+			 		          res.status, res.body ? res.body : "<empty>")));
+	}
+
 	return res;
 }
+
+
+static const char *
+HttpRequestMethodToString(HttpMethod method)
+{
+	switch (method)
+	{
+		case HTTP_GET:
+			return "GET";
+		case HTTP_HEAD:
+			return "HEAD";
+		case HTTP_POST:
+			return "POST";
+		case HTTP_PUT:
+			return "PUT";
+		case HTTP_DELETE:
+			return "DELETE";
+		default:
+			return "UNKNOWN";
+	}
+}

pg_lake_iceberg/src/init.c

@@ -139,6 +139,18 @@ _PG_init(void)
 							 GUC_NO_SHOW_ALL | GUC_NOT_IN_SAMPLE,
 							 NULL, NULL, NULL);
 
+
+	DefineCustomBoolVariable(
+							 "pg_lake_iceberg.http_client_trace_traffic",
+							 gettext_noop("When set to true, HTTP client logging is enabled."),
+							 NULL,
+							 &HttpClientTraceTraffic,
+							 false,
+							 PGC_USERSET,
+							 GUC_NO_SHOW_ALL | GUC_NOT_IN_SAMPLE,
+							 NULL, NULL, NULL);
+
+
 	DefineCustomStringVariable("pg_lake_iceberg.default_location_prefix",
 							   gettext_noop("Specifies the default location prefix for "
 											"iceberg tables. This is used when the location "