Add -config custom config file options. Fixes #6. (#12)

* Add -config custom config file options. Fixes #6.

* [skip ci] Improve usage

README.md

@@ -27,7 +27,8 @@ Options:
   -protoset The compiled protoset file. Alternative to proto. -proto takes precedence.
   -call		A fully-qualified method name in 'service/method' or 'service.method' format.
   -cert		The file containing the CA root cert file.
-  -cname	an override of the expect Server Cname presented by the server.
+  -cname	An override of the expect Server Cname presented by the server.
+  -config	Path to the config JSON file.
 
   -c  Number of requests to run concurrently. Total number of requests cannot
 	  be smaller than the concurrency level. Default is 50.
@@ -59,7 +60,7 @@ Options:
   -v  Print the version.
 ```
 
-Alternatively all settings can be set via `grpcannon.json` file if present in the same path as the `grpcannon` executable.
+Alternatively all settings can be set via `grpcannon.json` file if present in the same path as the `grpcannon` executable. A custom configuration file can be specified using `-config` option.
 
 ## Examples
 
@@ -99,6 +100,12 @@ And then use it as input to `grpcannon` with `-protoset` option:
 
 Note that only one of `-proto` or `-protoset` options will be used. `-proto` takes precedence.
 
+Using a custom config file:
+
+```sh
+grpcannon -config ./config.json
+```
+
 Example `grpcannon.json`
 
 ```json
@@ -112,7 +119,10 @@ Example `grpcannon.json`
     },
     "i": [
         "/path/to/protos"
-    ]
+    ],
+    "n": 4000,
+    "c": 40,
+    "host": "0.0.0.0:50051"
 }
 ```
 

cmd/grpcannon/main.go

@@ -24,7 +24,8 @@ var (
 	protoset = flag.String("protoset", "", `The .protoset file.`)
 	call     = flag.String("call", "", `A fully-qualified symbol name.`)
 	cert     = flag.String("cert", "", "Client certificate file. If Omitted insecure is used.")
-	cname    = flag.String("cname", "", "Server Cert CName Override - useful for self signed certs")
+	cname    = flag.String("cname", "", "Server Cert CName Override - useful for self signed certs.")
+	cPath    = flag.String("config", "", "Path to the config JSON file.")
 
 	c = flag.Int("c", 50, "Number of requests to run concurrently.")
 	n = flag.Int("n", 200, "Number of requests to run. Default is 200.")
@@ -58,7 +59,8 @@ Options:
   -protoset The compiled protoset file. Alternative to proto. -proto takes precedence.
   -call		A fully-qualified method name in 'service/method' or 'service.method' format.
   -cert		The file containing the CA root cert file.
-  -cname	an override of the expect Server Cname presented by the server.
+  -cname	An override of the expect Server Cname presented by the server.
+  -config	Path to the config JSON file.
 
   -c  Number of requests to run concurrently. Total number of requests cannot
 	  be smaller than the concurrency level. Default is 50.
@@ -102,20 +104,28 @@ func main() {
 		os.Exit(0)
 	}
 
-	if flag.NArg() < 1 {
-		usageAndExit("")
-	}
-
-	host := flag.Args()[0]
-
 	var cfg *config.Config
 
-	if _, err := os.Stat(localConfigName); err == nil {
+	cfgPath := strings.TrimSpace(*cPath)
+
+	if cfgPath != "" {
+		var err error
+		cfg, err = config.ReadConfig(cfgPath)
+		if err != nil {
+			errAndExit(err.Error())
+		}
+	} else if _, err := os.Stat(localConfigName); err == nil {
 		cfg, err = config.ReadConfig(localConfigName)
 		if err != nil {
 			errAndExit(err.Error())
 		}
 	} else {
+		if flag.NArg() < 1 {
+			usageAndExit("")
+		}
+
+		host := flag.Args()[0]
+
 		iPaths := []string{}
 		pathsTrimmed := strings.TrimSpace(*paths)
 		if pathsTrimmed != "" {

data_test.go

@@ -175,15 +175,15 @@ func TestData_createPayloads(t *testing.T) {
 	assert.NoError(t, err)
 	assert.NotNil(t, mtdClientStreaming)
 
-	mtdTestUnary, err := protodesc.GetMethodDesc(
+	mtdTestUnary, err := protodesc.GetMethodDescFromProto(
 		"data.DataTestService.TestCall",
 		"./testdata/data.proto",
 		nil)
 
 	assert.NoError(t, err)
 	assert.NotNil(t, mtdTestUnary)
 
-	mtdTestUnaryTwo, err := protodesc.GetMethodDesc(
+	mtdTestUnaryTwo, err := protodesc.GetMethodDescFromProto(
 		"data.DataTestService.TestCallTwo",
 		"./testdata/data.proto",
 		nil)