// Read is used to perform a read-only transaction that doesn't modify the state
// store. This is much more scaleable since it doesn't go through Raft and
// supports staleness, so this should be preferred if you're just performing
// reads.
func (t *Txn) Read(args *structs.TxnReadRequest, reply *structs.TxnReadResponse) error {
if done, err := t.srv.forward("Txn.Read", args, args, reply); done {
return err
}
defer metrics.MeasureSince([]string{"consul", "txn", "read"}, time.Now())
// We have to do this ourselves since we are not doing a blocking RPC.
t.srv.setQueryMeta(&reply.QueryMeta)
if args.RequireConsistent {
if err := t.srv.consistentRead(); err != nil {
return err
}
}
// Run the pre-checks before we perform the read.
acl, err := t.srv.resolveToken(args.Token)
if err != nil {
return err
}
reply.Errors = t.preCheck(acl, args.Ops)
if len(reply.Errors) > 0 {
return nil
}
// Run the read transaction.
state := t.srv.fsm.State()
reply.Results, reply.Errors = state.TxnRO(args.Ops)
if acl != nil {
reply.Results = FilterTxnResults(acl, reply.Results)
}
return nil
}
func TestTxn_Read_ACLDeny(t *testing.T) {
dir1, s1 := testServerWithConfig(t, func(c *Config) {
c.ACLDatacenter = "dc1"
c.ACLMasterToken = "root"
c.ACLDefaultPolicy = "deny"
})
defer os.RemoveAll(dir1)
defer s1.Shutdown()
codec := rpcClient(t, s1)
defer codec.Close()
testutil.WaitForLeader(t, s1.RPC, "dc1")
// Put in a key to read back.
state := s1.fsm.State()
d := &structs.DirEntry{
Key: "nope",
Value: []byte("hello"),
}
if err := state.KVSSet(1, d); err != nil {
t.Fatalf("err: %v", err)
}
// Create the ACL.
var id string
{
arg := structs.ACLRequest{
Datacenter: "dc1",
Op: structs.ACLSet,
ACL: structs.ACL{
Name: "User token",
Type: structs.ACLTypeClient,
Rules: testListRules,
},
WriteRequest: structs.WriteRequest{Token: "root"},
}
if err := msgpackrpc.CallWithCodec(codec, "ACL.Apply", &arg, &id); err != nil {
t.Fatalf("err: %v", err)
}
}
// Set up a transaction where every operation should get blocked due to
// ACLs.
arg := structs.TxnReadRequest{
Datacenter: "dc1",
Ops: structs.TxnOps{
&structs.TxnOp{
KV: &structs.TxnKVOp{
Verb: structs.KVSGet,
DirEnt: structs.DirEntry{
Key: "nope",
},
},
},
&structs.TxnOp{
KV: &structs.TxnKVOp{
Verb: structs.KVSGetTree,
DirEnt: structs.DirEntry{
Key: "nope",
},
},
},
&structs.TxnOp{
KV: &structs.TxnKVOp{
Verb: structs.KVSCheckSession,
DirEnt: structs.DirEntry{
Key: "nope",
},
},
},
&structs.TxnOp{
KV: &structs.TxnKVOp{
Verb: structs.KVSCheckIndex,
DirEnt: structs.DirEntry{
Key: "nope",
},
},
},
},
QueryOptions: structs.QueryOptions{
Token: id,
},
}
var out structs.TxnReadResponse
if err := msgpackrpc.CallWithCodec(codec, "Txn.Read", &arg, &out); err != nil {
t.Fatalf("err: %v", err)
}
// Verify the transaction's return value.
expected := structs.TxnReadResponse{
QueryMeta: structs.QueryMeta{
KnownLeader: true,
},
}
for i, op := range arg.Ops {
switch op.KV.Verb {
case structs.KVSGet, structs.KVSGetTree:
// These get filtered but won't result in an error.
default:
expected.Errors = append(expected.Errors, &structs.TxnError{i, permissionDeniedErr.Error()})
}
}
if !reflect.DeepEqual(out, expected) {
t.Fatalf("bad %v", out)
}
}