Prepare the driver to work with newer server releases than its own (#215)

* relax server's version checking

This commit relaxes the version check the driver does on connect: this
version compatibility is migrated on the server and the driver only
checks that server's version is more recent than a set minimum (that of
the release that applies version policy on the server).

* remove unused defines

remove superfluous defines

* add 'version' field into request objects

This commit adds the newly required 'version' field into the REST
request objects.

* only add the "version" to "query" objects

This commit fixes two issues:
- the "version" field is only required for "query" requst objects, but
not needed for "cursor" (paginating) ones;
- the lenght of the version field value is now correctly estimated in
CBOR encoding.

* update unit tests to "version" in query-req only

Update position of the "version" field in expected output of the request
object.

Author: bpintea

driver/connect.c

@@ -97,6 +97,11 @@
 #define ESINFO_KEY_VERSION	"version"
 #define ESINFO_KEY_NUMBER	"number"
 
+/* "base" of the version number (how many values supported for each version
+ * constituent: major, minor, revision) */
+#define VER_LEVEL_MULTI		100L
+
+
 /* structure for one row returned by the ES.
  * This is a mirror of elasticsearch_type, with length-or-indicator fields
  * for each of the members in elasticsearch_type */
@@ -1411,28 +1416,6 @@ SQLRETURN config_dbc(esodbc_dbc_st *dbc, esodbc_dsn_attrs_st *attrs)
 		goto err;
 	}
 
-	/*
-	 * Version checking mode
-	 */
-	if (EQ_CASE_WSTR(&attrs->version_checking,
-			&MK_WSTR(ESODBC_DSN_VC_STRICT))
-		|| EQ_CASE_WSTR(&attrs->version_checking,
-			&MK_WSTR(ESODBC_DSN_VC_MAJOR))
-#			ifndef NDEBUG
-		|| EQ_CASE_WSTR(&attrs->version_checking,
-			&MK_WSTR(ESODBC_DSN_VC_NONE))
-#			endif /* NDEBUG */
-	) {
-		dbc->srv_ver.checking = (unsigned char)attrs->version_checking.str[0];
-		DBGH(dbc, "version checking mode: %c.", dbc->srv_ver.checking);
-	} else {
-		ERRH(dbc, "unknown version checking mode '" LWPDL "'.",
-			LWSTR(&attrs->version_checking));
-		SET_HDIAG(dbc, SQL_STATE_HY000, "invalid version checking mode "
-			"setting", 0);
-		goto err;
-	}
-
 	/* "multifield leniency" param */
 	dbc->mfield_lenient = wstr2bool(&attrs->mfield_lenient);
 	INFOH(dbc, "multifield lenient: %s.",
@@ -1523,10 +1506,10 @@ void cleanup_dbc(esodbc_dbc_st *dbc)
 	} else {
 		assert(dbc->no_types == 0);
 	}
-	if (dbc->srv_ver.string.cnt) { /* .str might be compromized by the union */
-		free(dbc->srv_ver.string.str);
-		dbc->srv_ver.string.str = NULL;
-		dbc->srv_ver.string.cnt = 0;
+	if (dbc->srv_ver.str) {
+		free(dbc->srv_ver.str);
+		dbc->srv_ver.str = NULL;
+		dbc->srv_ver.cnt = 0;
 	}
 	if (dbc->catalog.str) {
 		free(dbc->catalog.str);
@@ -1652,10 +1635,59 @@ static BOOL parse_es_version_json(esodbc_dbc_st *dbc, cstr_st *rsp_body,
 		return FALSE;
 	}
 	version->str = (SQLWCHAR *)UJReadString(o_number, &version->cnt);
-	DBGH(dbc, "Elasticsearch'es version number: [%zu] `" LWPDL "`.",
+	DBGH(dbc, "Elasticsearch's version number: [%zu] `" LWPDL "`.",
 		version->cnt, LWSTR(version));
 	return TRUE;
 }
+
+/* parses a Major.Minor.Revison version format and returns a numerical value
+ * of it */
+static long version_to_id(wstr_st *ver)
+{
+	SQLWCHAR *stop;
+	long id, val;
+
+	assert(ver->str[ver->cnt] == L'\0');
+
+	errno = 0;
+	stop = ver->str;
+
+	/* parse major */
+	id = wcstol(stop, &stop, /*base*/10);
+	if (errno || VER_LEVEL_MULTI <= id || id <= 0) {
+		return -1;
+	}
+	if (*stop != L'.') {
+		return -1;
+	} else {
+		stop ++;
+	}
+	id *= VER_LEVEL_MULTI;
+
+	/* parse minor */
+	val = wcstol(stop, &stop, /*base*/10);
+	if (errno || VER_LEVEL_MULTI <= val || val < 0) {
+		return -1;
+	}
+	if (*stop != L'.') {
+		return -1;
+	} else {
+		stop ++;
+	}
+	id += val;
+	id *= VER_LEVEL_MULTI;
+
+	/* parse minor */
+	val = wcstol(stop, &stop, /*base*/10);
+	if (errno || VER_LEVEL_MULTI <= val || val < 0) {
+		return -1;
+	}
+	id += val;
+	id *= VER_LEVEL_MULTI;
+
+	return id;
+}
+
 /*
  * Note: not thread safe: only usable on connection setup.
  */
@@ -1667,16 +1699,17 @@ static SQLRETURN check_server_version(esodbc_dbc_st *dbc)
 	BOOL is_json;
 	SQLRETURN ret;
 	void *state = NULL;
-	unsigned char ver_checking;
-	wstr_st own_ver = WSTR_INIT(STR(DRV_VERSION)); /*build-time define*/
-	wstr_st es_ver, ver_no;
+	static wstr_st min_es_ver = WSTR_INIT(ESODBC_MIN_ES_VER);
+	wstr_st es_ver;
 	cstr_st es_ver_c;
-	static const wchar_t err_msg_fmt[] = L"Version mismatch between server ("
-		WPFWP_LDESC ") and driver (" WPFWP_LDESC "). Please use a driver whose"
-		" version matches that of your server.";
+	long es_ver_l, min_es_ver_l;
+	static const wchar_t err_msg_fmt[] = L"Elasticsearch's version ("
+		WPFWP_LDESC ") is below minimum required (" ESODBC_MIN_ES_VER ") "
+		"version. Please use a driver whose version matches that of your "
+		"server.";
 	/* 32: max length of the version strings for which the explicit message
 	 * above is provided. */
-	SQLWCHAR wbuff[sizeof(err_msg_fmt)/sizeof(err_msg_fmt[0]) + 2*32];
+	SQLWCHAR wbuff[sizeof(err_msg_fmt)/sizeof(err_msg_fmt[0]) + 32];
 	int n;
 
 	ret = dbc_curl_set_url(dbc, ESODBC_CURL_ROOT);
@@ -1711,54 +1744,43 @@ static SQLRETURN check_server_version(esodbc_dbc_st *dbc)
 		goto err;
 	}
 
-	ver_checking = dbc->srv_ver.checking;
 	/* version is returned to application, which requires a NTS => +1 for \0 */
-	dbc->srv_ver.string.str = malloc((n + 1) * sizeof(SQLWCHAR));
-	if (! dbc->srv_ver.string.str) {
+	dbc->srv_ver.str = malloc((n + 1) * sizeof(SQLWCHAR));
+	if (! dbc->srv_ver.str) {
 		ERRNH(dbc, "OOM for %zu.", (n + 1) * sizeof(SQLWCHAR));
 		post_diagnostic(dbc, SQL_STATE_HY001, NULL, 0);
 		goto err;
 	} else if (is_json) {
-		memcpy(dbc->srv_ver.string.str, es_ver.str, n * sizeof(SQLWCHAR));
-	} else if (ascii_c2w(es_ver_c.str, dbc->srv_ver.string.str, n) < 0) {
+		memcpy(dbc->srv_ver.str, es_ver.str, n * sizeof(SQLWCHAR));
+	} else if (ascii_c2w(es_ver_c.str, dbc->srv_ver.str, n) < 0) {
 		/* non-ASCII or empty */
-		ERRH(dbc, "Elasticsearch version string is invalid.");
+		BUGH(dbc, "Elasticsearch version string is invalid.");
 		goto err;
 	}
-	dbc->srv_ver.string.cnt = n;
-	dbc->srv_ver.string.str[n] = 0;
-	ver_no = dbc->srv_ver.string;
+	dbc->srv_ver.cnt = n;
+	dbc->srv_ver.str[n] = 0;
 
-#	ifndef NDEBUG
-	/* strip any qualifiers (=anything following a first `-`) in debug mode */
-	wtrim_at(&ver_no, L'-');
-	wtrim_at(&own_ver, L'-');
-#	endif /* !NDEBUG */
-
-	if (tolower(ver_checking) == tolower(ESODBC_DSN_VC_MAJOR[0])) {
-		/* trim versions to the first dot, i.e. major version */
-		wtrim_at(&ver_no, L'.');
-		wtrim_at(&own_ver, L'.');
-	}
-
-	if (tolower(ver_checking) != tolower(ESODBC_DSN_VC_NONE[0])) {
-		if (! EQ_WSTR(&ver_no, &own_ver)) {
-			ERRH(dbc, "version mismatch: server: " LWPDL ", "
-				"own: " LWPDL ".", LWSTR(&ver_no), LWSTR(&own_ver));
-			n = swprintf(wbuff, sizeof(wbuff)/sizeof(wbuff[0]),
-					err_msg_fmt, LWSTR(&ver_no), LWSTR(&own_ver));
-			ret = post_diagnostic(dbc, SQL_STATE_HY000, (n <= 0) ?
-					L"Version mismatch between server and driver" :
-					wbuff, 0);
-		} else {
-			INFOH(dbc, "server and driver versions aligned to: " LWPDL ".",
-				LWSTR(&own_ver));
-			ret = SQL_SUCCESS;
-		}
-#	ifndef NDEBUG
+	min_es_ver_l = version_to_id(&min_es_ver);
+	assert(0 < min_es_ver_l);
+	es_ver_l = version_to_id(&dbc->srv_ver);
+	if (es_ver_l <= 0) {
+		BUGH(dbc, "failed to parse Elasticsearch version `" LWPDL "`.",
+			LWSTR(&dbc->srv_ver));
+		goto err;
+	}
+	if (es_ver_l < min_es_ver_l) {
+		ERRH(dbc, "Elasticsearch version `" LWPDL "` is below minimum required"
+			" `" LWPDL "`.", LWSTR(&dbc->srv_ver), LWSTR(&min_es_ver));
+		n = swprintf(wbuff, sizeof(wbuff)/sizeof(wbuff[0]),
+				err_msg_fmt, LWSTR(&dbc->srv_ver));
+		ret = post_diagnostic(dbc, SQL_STATE_HY000, (n <= 0) ?
+				L"Version mismatch between server and driver" :
+				wbuff, 0);
 	} else {
-		WARNH(dbc, "version checking disabled.");
-#	endif /* !NDEBUG */
+		INFOH(dbc, "server version (" LWPDL ") %s minimum required "
+			"(" ESODBC_MIN_ES_VER ").", LWSTR(&dbc->srv_ver),
+			es_ver_l == min_es_ver_l ? "meets" : "exceeds");
+		ret = SQL_SUCCESS;
 	}
 
 	free(rsp_body.str);

driver/defs.h

@@ -122,8 +122,6 @@
 /* maximum DNS attribute value lenght (should be long enought to accomodate a
  * decently long FQ file path name) */
 #define ESODBC_DSN_MAX_ATTR_LEN			1024
-/* sample DSN name provisioned with the installation  */
-#define ESODBC_DSN_SAMPLE_NAME			"Elasticsearch ODBC Sample DSN"
 
 /* SQL plugin's REST endpoint for SQL */
 #define ELASTIC_SQL_PATH				"/_sql"
@@ -139,6 +137,8 @@
 #define ESODBC_DRIVER_VER	STR(DRV_VERSION) \
 	"(" STR(DRV_SRC_VER) "," STR(DRV_ENCODING) "," STR(DRV_BUILD_TYPE) ")"
 #define ESODBC_ELASTICSEARCH_NAME	"Elasticsearch"
+/* the driver will work with an ES node of this version and higher */
+#define ESODBC_MIN_ES_VER			"7.7.0"
 
 /*
  * Config defaults
@@ -176,8 +176,6 @@
 /* default of scientific floats printing */
 #define ESODBC_DEF_SCI_FLOATS		ESODBC_DSN_FLTS_DEF
 #define ESODBC_PWD_VAL_SUBST		"<redacted>"
-/* default version checking mode: strict, major, none (dbg only) */
-#define ESODBC_DEF_VERSION_CHECKING	ESODBC_DSN_VC_STRICT
 #define ESODBC_DEF_MFIELD_LENIENT	"true"
 #define ESODBC_DEF_ESC_PVA			"true"
 #define ESODBC_DEF_IDX_INC_FROZEN	"false"

driver/dsn.c

@@ -880,9 +880,6 @@ void assign_dsn_defaults(esodbc_dsn_attrs_st *attrs)
 	res |= assign_dsn_attr(attrs, &MK_WSTR(ESODBC_DSN_MAX_BODY_SIZE_MB),
 			&MK_WSTR(ESODBC_DEF_MAX_BODY_SIZE_MB),
 			/*overwrite?*/FALSE);
-	res |= assign_dsn_attr(attrs, &MK_WSTR(ESODBC_DSN_VERSION_CHECKING),
-			&MK_WSTR(ESODBC_DEF_VERSION_CHECKING),
-			/*overwrite?*/FALSE);
 
 	res |= assign_dsn_attr(attrs,
 			&MK_WSTR(ESODBC_DSN_APPLY_TZ), &MK_WSTR(ESODBC_DEF_APPLY_TZ),

driver/dsn.h

@@ -51,10 +51,6 @@
 #define ESODBC_DSN_CMPSS_AUTO		"auto"
 #define ESODBC_DSN_CMPSS_ON			"on"
 #define ESODBC_DSN_CMPSS_OFF		"off"
-/* VersionChecking values */
-#define ESODBC_DSN_VC_STRICT		"strict"
-#define ESODBC_DSN_VC_MAJOR			"major"
-#define ESODBC_DSN_VC_NONE			"none"
 /* Floats printing */
 #define ESODBC_DSN_FLTS_DEF			"default"
 #define ESODBC_DSN_FLTS_SCI			"scientific"

driver/handles.h

@@ -132,10 +132,7 @@ typedef struct struct_dbc {
 	wstr_st dsn; /* data source name SQLGetInfo(SQL_DATA_SOURCE_NAME) */
 	wstr_st server; /* ~ name; requested with SQLGetInfo(SQL_SERVER_NAME) */
 	wstr_st catalog; /* cached value; checked against if app setting it */
-	union {
-		wstr_st string; /* version: SQLGetInfo(SQL_DBMS_VER)  */
-		unsigned char checking; /* first letter of DSN config option value */
-	} srv_ver; /* server version */
+	wstr_st srv_ver; /* server version: SQLGetInfo(SQL_DBMS_VER) */
 	cstr_st url; /* SQL URL (posts) */
 	cstr_st close_url; /* SQL close URL (posts) */
 	cstr_st root_url; /* root URL (gets) */

driver/info.c

@@ -306,8 +306,8 @@ static SQLRETURN getinfo_dbms_product(
 					StringLengthPtr);
 		case SQL_DBMS_VER:
 			DBGH(dbc, "requested: DBMS version (`" LWPDL "`).",
-				LWSTR(&dbc->srv_ver.string));
-			return write_wstr(dbc, InfoValue, &dbc->srv_ver.string,
+				LWSTR(&dbc->srv_ver));
+			return write_wstr(dbc, InfoValue, &dbc->srv_ver,
 					BufferLength, StringLengthPtr);
 	}
 	*handled = FALSE;

driver/queries.c

@@ -41,6 +41,7 @@ static SQLRETURN statement_params_len_cbor(esodbc_stmt_st *stmt,
 	size_t *enc_len, size_t *conv_len);
 
 static thread_local cstr_st tz_param;
+static cstr_st version = CSTR_INIT(STR(DRV_VERSION)); /* build-time define */
 
 static BOOL print_tz_param(long tz_dst_offt)
 {
@@ -142,10 +143,18 @@ static inline BOOL update_tz_param()
 
 BOOL queries_init()
 {
+	char *ptr;
+
 	/* for the casts in this module */
 	ASSERT_INTEGER_TYPES_EQUAL(wchar_t, SQLWCHAR);
 	ASSERT_INTEGER_TYPES_EQUAL(char, SQLCHAR);
 
+	/* trim qualifiers */
+	ptr = strchr(version.str, '-');
+	if (ptr) {
+		version.cnt = ptr - version.str;
+	}
+
 	/* needed to correctly run the unit tests */
 	return update_tz_param();
 }
@@ -2973,7 +2982,9 @@ static SQLRETURN statement_len_cbor(esodbc_stmt_st *stmt, size_t *enc_len,
 		/* "time_zone": "-05:45" */
 		bodylen += cbor_str_obj_len(sizeof(REQ_KEY_TIMEZONE) - 1);
 		bodylen += cbor_str_obj_len(tz_param.cnt); /* lax len */
-		*keys += 3; /* field_m._val., idx._inc._frozen, time_zone */
+		bodylen += cbor_str_obj_len(sizeof(REQ_KEY_VERSION) - 1);
+		bodylen += cbor_str_obj_len(version.cnt);
+		*keys += 4; /* field_m._val., idx._inc._frozen, time_zone, version */
 	}
 	bodylen += cbor_str_obj_len(sizeof(REQ_KEY_MODE) - 1);
 	bodylen += cbor_str_obj_len(sizeof(REQ_VAL_MODE) - 1);
@@ -3033,9 +3044,12 @@ static SQLRETURN statement_len_json(esodbc_stmt_st *stmt, size_t *outlen)
 		/* "time_zone": "-05:45" */
 		bodylen += sizeof(JSON_KEY_TIMEZONE) - 1;
 		bodylen += tz_param.cnt;
+		/* "version": */
+		bodylen += sizeof(JSON_KEY_VERSION) - 1;
+		bodylen += version.cnt + /* 2x`"` */2;
 	}
-	bodylen += sizeof(JSON_KEY_VAL_MODE) - 1; /* "mode": */
-	bodylen += sizeof(JSON_KEY_CLT_ID) - 1; /* "client_id": */
+	bodylen += sizeof(JSON_KEY_VAL_MODE) - 1; /* "mode": "ODBC" */
+	bodylen += sizeof(JSON_KEY_CLT_ID) - 1; /* "client_id": "odbcXX" */
 	/* TODO: request_/page_timeout */
 	bodylen += 1; /* } */
 
@@ -3307,6 +3321,12 @@ static SQLRETURN serialize_to_cbor(esodbc_stmt_st *stmt, cstr_st *dest,
 		}
 		err = cbor_encode_text_string(&map, tz.str, tz.cnt);
 		FAIL_ON_CBOR_ERR(stmt, err);
+		/* version */
+		err = cbor_encode_text_string(&map, REQ_KEY_VERSION,
+				sizeof(REQ_KEY_VERSION) - 1);
+		FAIL_ON_CBOR_ERR(stmt, err);
+		err = cbor_encode_text_string(&map, version.str, version.cnt);
+		FAIL_ON_CBOR_ERR(stmt, err);
 	}
 	/* mode : ODBC */
 	err = cbor_encode_text_string(&map, REQ_KEY_MODE,
@@ -3424,10 +3444,18 @@ static SQLRETURN serialize_to_json(esodbc_stmt_st *stmt, cstr_st *dest)
 				sizeof(JSON_VAL_TIMEZONE_Z) - 1);
 			pos += sizeof(JSON_VAL_TIMEZONE_Z) - 1;
 		}
+		/* "version": ... */
+		memcpy(body + pos, JSON_KEY_VERSION, sizeof(JSON_KEY_VERSION) - 1);
+		pos += sizeof(JSON_KEY_VERSION) - 1;
+		body[pos ++] = '"';
+		memcpy(body + pos, version.str, version.cnt);
+		pos += version.cnt;
+		body[pos ++] = '"';
 	}
-	/* "mode": */
+	/* "mode": "ODBC" */
 	memcpy(body + pos, JSON_KEY_VAL_MODE, sizeof(JSON_KEY_VAL_MODE) - 1);
 	pos += sizeof(JSON_KEY_VAL_MODE) - 1;
+	/* "client_id": "odbcXX" */
 	memcpy(body + pos, JSON_KEY_CLT_ID, sizeof(JSON_KEY_CLT_ID) - 1);
 	pos += sizeof(JSON_KEY_CLT_ID) - 1;
 	body[pos ++] = '}';