rados: add MgrCommand and MgrCommandWithInputBuffer functions

Add functions for issuing commands to ceph mgrs with
MgrCommand and MgrCommandWithInputBuffer, implemented simliarly
to the other *Command style functions.

Signed-off-by: John Mulligan <jmulligan@redhat.com>

rados/command.go

@@ -130,3 +130,65 @@ func (c *Conn) pgCommand(pgid []byte, args [][]byte, inputBuffer []byte) ([]byte
 
 	return buffer, info, nil
 }
+
+// MgrCommand sends a command to a ceph-mgr.
+func (c *Conn) MgrCommand(args [][]byte) ([]byte, string, error) {
+	return c.mgrCommand(args, nil)
+}
+
+// MgrCommandWithInputBuffer sends a command, with an input buffer, to a ceph-mgr.
+func (c *Conn) MgrCommandWithInputBuffer(args [][]byte, inputBuffer []byte) ([]byte, string, error) {
+	return c.mgrCommand(args, inputBuffer)
+}
+
+// Implements:
+//  int rados_mgr_command(rados_t cluster, const char **cmd,
+//                         size_t cmdlen, const char *inbuf,
+//                         size_t inbuflen, char **outbuf,
+//                         size_t *outbuflen, char **outs,
+//                          size_t *outslen);
+func (c *Conn) mgrCommand(args [][]byte, inputBuffer []byte) ([]byte, string, error) {
+	argc := len(args)
+	argv := make([]*C.char, argc)
+
+	for i, arg := range args {
+		argv[i] = C.CString(string(arg))
+		defer C.free(unsafe.Pointer(argv[i]))
+	}
+
+	var (
+		info               string
+		buffer             []byte
+		outs, outbuf       *C.char
+		outslen, outbuflen C.size_t
+	)
+	inbuf := C.CString(string(inputBuffer))
+	inbufLen := len(inputBuffer)
+	defer C.free(unsafe.Pointer(inbuf))
+
+	ret := C.rados_mgr_command(
+		c.cluster,
+		&argv[0],
+		C.size_t(argc),
+		inbuf,
+		C.size_t(inbufLen),
+		&outbuf,
+		&outbuflen,
+		&outs,
+		&outslen)
+
+	if outslen > 0 {
+		info = C.GoStringN(outs, C.int(outslen))
+		C.free(unsafe.Pointer(outs))
+	}
+	if outbuflen > 0 {
+		buffer = C.GoBytes(unsafe.Pointer(outbuf), C.int(outbuflen))
+		C.free(unsafe.Pointer(outbuf))
+	}
+	if ret != 0 {
+		err := getError(ret)
+		return nil, info, err
+	}
+
+	return buffer, info, nil
+}

rados/command_mimic_test.go

@@ -0,0 +1,37 @@
+// +build !luminous
+
+package rados
+
+import (
+	"encoding/json"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// A real test using input buffer is hard to find for mgr.
+// The simplest does not work on luminous, so we simply don't
+// provide the test for luminous.
+
+func (suite *RadosTestSuite) TestMgrCommandWithInputBuffer() {
+	suite.SetupConnection()
+
+	command, err := json.Marshal(
+		map[string]string{"prefix": "crash post", "format": "json"})
+	assert.NoError(suite.T(), err)
+
+	buf, info, err := suite.conn.MgrCommandWithInputBuffer(
+		[][]byte{command}, []byte(`{"crash_id": "foobar", "timestamp": "2020-04-10 15:08:34.659679Z"}`))
+	assert.NoError(suite.T(), err)
+	assert.Equal(suite.T(), info, "")
+	assert.Len(suite.T(), buf, 0)
+
+	command, err = json.Marshal(
+		map[string]string{"prefix": "crash rm", "id": "foobar", "format": "json"})
+	assert.NoError(suite.T(), err)
+
+	buf, info, err = suite.conn.MgrCommandWithInputBuffer(
+		[][]byte{command}, nil)
+	assert.NoError(suite.T(), err)
+	assert.Equal(suite.T(), info, "")
+	assert.Len(suite.T(), buf, 0)
+}

rados/command_test.go

@@ -87,3 +87,45 @@ func (suite *RadosTestSuite) TestPGCommand() {
 	err = json.Unmarshal(buf, &message)
 	assert.NoError(suite.T(), err)
 }
+
+func (suite *RadosTestSuite) TestMgrCommandDescrptions() {
+	suite.SetupConnection()
+
+	command, err := json.Marshal(
+		map[string]string{"prefix": "get_command_descriptions", "format": "json"})
+	assert.NoError(suite.T(), err)
+
+	buf, info, err := suite.conn.MgrCommand([][]byte{command})
+	assert.NoError(suite.T(), err)
+	assert.Equal(suite.T(), info, "")
+
+	var message map[string]interface{}
+	err = json.Unmarshal(buf, &message)
+	assert.NoError(suite.T(), err)
+}
+
+func (suite *RadosTestSuite) TestMgrCommand() {
+	suite.SetupConnection()
+
+	command, err := json.Marshal(
+		map[string]string{"prefix": "balancer status", "format": "json"})
+	assert.NoError(suite.T(), err)
+
+	buf, info, err := suite.conn.MgrCommand([][]byte{command})
+	assert.NoError(suite.T(), err)
+	assert.Equal(suite.T(), info, "")
+
+	var message map[string]interface{}
+	err = json.Unmarshal(buf, &message)
+	assert.NoError(suite.T(), err)
+}
+
+func (suite *RadosTestSuite) TestMgrCommandMalformedCommand() {
+	suite.SetupConnection()
+
+	command := []byte("JUNK!")
+	buf, info, err := suite.conn.MgrCommand([][]byte{command})
+	assert.Error(suite.T(), err)
+	assert.NotEqual(suite.T(), info, "")
+	assert.Len(suite.T(), buf, 0)
+}