[#117] scenarios: Refactor data generator construction

1. Make it easier to change new parameters.
2. Fix a bug where the generator was created even for read-only
   scenarios.

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

scenarios/grpc.js

@@ -1,4 +1,3 @@
-import datagen from 'k6/x/frostfs/datagen';
 import native from 'k6/x/frostfs/native';
 import logging from 'k6/x/frostfs/logging';
 import registry from 'k6/x/frostfs/registry';
@@ -7,6 +6,7 @@ import { sleep } from 'k6';
 import { textSummary } from './libs/k6-summary-0.0.2.js';
 import { parseEnv } from './libs/env-parser.js';
 import { uuidv4 } from './libs/k6-utils-1.4.0.js';
+import { newGenerator } from './libs/datagen.js';
 
 parseEnv();
 
@@ -63,13 +63,11 @@ if (registry_enabled) {
     )
 }
 
-
-const generator = datagen.generator(1024 * parseInt(__ENV.WRITE_OBJ_SIZE), __ENV.PAYLOAD_TYPE || "");
-
 const scenarios = {};
 
 const write_vu_count = parseInt(__ENV.WRITERS || '0');
 const write_grpc_chunk_size = 1024 * parseInt(__ENV.GRPC_CHUNK_SIZE || '0')
+const generator = newGenerator(write_vu_count > 0);
 if (write_vu_count > 0) {
     scenarios.write = {
         executor: 'constant-vus',

scenarios/grpc_car.js

@@ -1,4 +1,3 @@
-import datagen from 'k6/x/frostfs/datagen';
 import native from 'k6/x/frostfs/native';
 import logging from 'k6/x/frostfs/logging';
 import registry from 'k6/x/frostfs/registry';
@@ -7,6 +6,7 @@ import { sleep } from 'k6';
 import { textSummary } from './libs/k6-summary-0.0.2.js';
 import { parseEnv } from './libs/env-parser.js';
 import { uuidv4 } from './libs/k6-utils-1.4.0.js';
+import { newGenerator } from './libs/datagen.js';
 
 parseEnv();
 
@@ -63,8 +63,6 @@ if (registry_enabled) {
     )
 }
 
-const generator = datagen.generator(1024 * parseInt(__ENV.WRITE_OBJ_SIZE), __ENV.PAYLOAD_TYPE || "");
-
 const scenarios = {};
 
 const time_unit = __ENV.TIME_UNIT || '1s';
@@ -72,6 +70,7 @@ const pre_alloc_write_vus = parseInt(__ENV.PRE_ALLOC_WRITERS || '0');
 const max_write_vus = parseInt(__ENV.MAX_WRITERS || pre_alloc_write_vus);
 const write_rate = parseInt(__ENV.WRITE_RATE || '0');
 const write_grpc_chunk_size = 1024 * parseInt(__ENV.GRPC_CHUNK_SIZE || '0')
+const generator = newGenerator(write_rate > 0);
 if (write_rate > 0) {
     scenarios.write = {
         executor: 'constant-arrival-rate',

scenarios/http.js

@@ -1,4 +1,3 @@
-import datagen from 'k6/x/frostfs/datagen';
 import logging from 'k6/x/frostfs/logging';
 import registry from 'k6/x/frostfs/registry';
 import http from 'k6/http';
@@ -7,6 +6,7 @@ import { sleep } from 'k6';
 import { textSummary } from './libs/k6-summary-0.0.2.js';
 import { parseEnv } from './libs/env-parser.js';
 import { uuidv4 } from './libs/k6-utils-1.4.0.js';
+import { newGenerator } from './libs/datagen.js';
 
 parseEnv();
 
@@ -31,11 +31,10 @@ const obj_registry = registry_enabled ? registry.open(__ENV.REGISTRY_FILE) : und
 
 const duration = __ENV.DURATION;
 
-const generator = datagen.generator(1024 * parseInt(__ENV.WRITE_OBJ_SIZE), __ENV.PAYLOAD_TYPE || "");
-
 const scenarios = {};
 
 const write_vu_count = parseInt(__ENV.WRITERS || '0');
+const generator = newGenerator(write_vu_count > 0);
 if (write_vu_count > 0) {
     scenarios.write = {
         executor: 'constant-vus',

scenarios/libs/datagen.js

@@ -0,0 +1,8 @@
+import datagen from 'k6/x/frostfs/datagen';
+
+export function newGenerator(condition) {
+	if (condition) {
+		return datagen.generator(1024 * parseInt(__ENV.WRITE_OBJ_SIZE), __ENV.PAYLOAD_TYPE || "");
+	}
+	return undefined;
+}

scenarios/local.js

@@ -1,4 +1,3 @@
-import datagen from 'k6/x/frostfs/datagen';
 import local from 'k6/x/frostfs/local';
 import logging from 'k6/x/frostfs/logging';
 import registry from 'k6/x/frostfs/registry';
@@ -7,6 +6,7 @@ import { textSummary } from './libs/k6-summary-0.0.2.js';
 import { parseEnv } from './libs/env-parser.js';
 import { uuidv4 } from './libs/k6-utils-1.4.0.js';
 import exec from 'k6/execution';
+import { newGenerator } from './libs/datagen.js';
 
 parseEnv();
 
@@ -47,11 +47,10 @@ if (registry_enabled && delete_age) {
     );
 }
 
-const generator = datagen.generator(1024 * parseInt(__ENV.WRITE_OBJ_SIZE), __ENV.PAYLOAD_TYPE || "");
-
 const scenarios = {};
 
 const write_vu_count = parseInt(__ENV.WRITERS || '0');
+const generator = newGenerator(write_vu_count > 0);
 if (write_vu_count > 0) {
     scenarios.write = {
         executor: 'constant-vus',

scenarios/s3.js

@@ -1,4 +1,3 @@
-import datagen from 'k6/x/frostfs/datagen';
 import logging from 'k6/x/frostfs/logging';
 import registry from 'k6/x/frostfs/registry';
 import s3 from 'k6/x/frostfs/s3';
@@ -7,6 +6,7 @@ import { sleep } from 'k6';
 import { textSummary } from './libs/k6-summary-0.0.2.js';
 import { parseEnv } from './libs/env-parser.js';
 import { uuidv4 } from './libs/k6-utils-1.4.0.js';
+import { newGenerator } from './libs/datagen.js';
 
 parseEnv();
 
@@ -62,11 +62,10 @@ if (registry_enabled) {
     )
 }
 
-const generator = datagen.generator(1024 * parseInt(__ENV.WRITE_OBJ_SIZE), __ENV.PAYLOAD_TYPE || "");
-
 const scenarios = {};
 
 const write_vu_count = parseInt(__ENV.WRITERS || '0');
+const generator = newGenerator(write_vu_count > 0);
 if (write_vu_count > 0) {
     scenarios.write = {
         executor: 'constant-vus',

scenarios/s3_car.js

@@ -1,4 +1,3 @@
-import datagen from 'k6/x/frostfs/datagen';
 import logging from 'k6/x/frostfs/logging';
 import registry from 'k6/x/frostfs/registry';
 import s3 from 'k6/x/frostfs/s3';
@@ -7,6 +6,7 @@ import { sleep } from 'k6';
 import { textSummary } from './libs/k6-summary-0.0.2.js';
 import { parseEnv } from './libs/env-parser.js';
 import { uuidv4 } from './libs/k6-utils-1.4.0.js';
+import { newGenerator } from './libs/datagen.js';
 
 parseEnv();
 
@@ -62,14 +62,13 @@ if (registry_enabled) {
     )
 }
 
-const generator = datagen.generator(1024 * parseInt(__ENV.WRITE_OBJ_SIZE), __ENV.PAYLOAD_TYPE || "");
-
 const scenarios = {};
 
 const time_unit = __ENV.TIME_UNIT || '1s';
 const pre_alloc_write_vus = parseInt(__ENV.PRE_ALLOC_WRITERS || '0');
 const max_write_vus = parseInt(__ENV.MAX_WRITERS || pre_alloc_write_vus);
 const write_rate = parseInt(__ENV.WRITE_RATE || '0');
+const generator = newGenerator(write_rate > 0);
 if (write_rate > 0) {
     scenarios.write = {
         executor: 'constant-arrival-rate',

scenarios/s3_multipart.js

@@ -1,4 +1,3 @@
-import datagen from 'k6/x/frostfs/datagen';
 import logging from 'k6/x/frostfs/logging';
 import registry from 'k6/x/frostfs/registry';
 import s3 from 'k6/x/frostfs/s3';
@@ -7,6 +6,7 @@ import {sleep} from 'k6';
 import {textSummary} from './libs/k6-summary-0.0.2.js';
 import {parseEnv} from './libs/env-parser.js';
 import {uuidv4} from './libs/k6-utils-1.4.0.js';
+import { newGenerator } from './libs/datagen.js';
 
 parseEnv();
 
@@ -29,8 +29,6 @@ const obj_registry = registry_enabled ? registry.open(__ENV.REGISTRY_FILE) : und
 
 const duration = __ENV.DURATION;
 
-const generator = datagen.generator(1024 * parseInt(__ENV.WRITE_OBJ_SIZE), __ENV.PAYLOAD_TYPE || "");
-
 const scenarios = {};
 
 const write_vu_count = parseInt(__ENV.WRITERS || '0');
@@ -43,6 +41,7 @@ if (write_multipart_vu_count < 1) {
     throw 'number of parts (env WRITERS_MULTIPART) to upload in parallel should be greater than 0';
 }
 
+const generator = newGenerator(write_vu_count > 0 || write_multipart_vu_count > 0);
 if (write_vu_count > 0) {
     scenarios.write_multipart = {
         executor: 'constant-vus',

scenarios/s3local.js

@@ -1,4 +1,3 @@
-import datagen from 'k6/x/frostfs/datagen';
 import logging from 'k6/x/frostfs/logging';
 import registry from 'k6/x/frostfs/registry';
 import s3local from 'k6/x/frostfs/s3local';
@@ -7,6 +6,7 @@ import { textSummary } from './libs/k6-summary-0.0.2.js';
 import { parseEnv } from './libs/env-parser.js';
 import { uuidv4 } from './libs/k6-utils-1.4.0.js';
 import exec from 'k6/execution';
+import { newGenerator } from './libs/datagen.js';
 
 parseEnv();
 
@@ -61,11 +61,10 @@ if (registry_enabled) {
 
 const duration = __ENV.DURATION;
 
-const generator = datagen.generator(1024 * parseInt(__ENV.WRITE_OBJ_SIZE), __ENV.PAYLOAD_TYPE || "");
-
 const scenarios = {};
 
 const write_vu_count = parseInt(__ENV.WRITERS || '0');
+const generator = newGenerator(write_vu_count > 0);
 if (write_vu_count > 0) {
     scenarios.write = {
         executor: 'constant-vus',