lnd.xprv/subrpcserver_config.go

264 lines
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config+rpc: create new generalized dynamic sub rpc server config framework In this commit, we add the glue infrastructure to make the sub RPC server system work properly. Our high level goal is the following: using only the lnrpc package (with no visibility into the sub RPC servers), the RPC server is able to find, create, run, and manage the entire set of present and future sub RPC servers. In order to achieve this, we use the reflect package and build tags heavily to permit a loosely coupled configuration parsing system for the sub RPC servers. We start with a new `subRpcServerConfigs` struct which is _always_ present. This struct has its own group, and will house a series of sub-configs, one for each sub RPC server. Each sub-config is actually gated behind a build flag, and can be used to allow users on the command line or in the config to specify arguments related to the sub-server. If the config isn't present, then we don't attempt to parse it at all, if it is, then that means the RPC server has been registered, and we should parse the contents of its config. The `subRpcServerConfigs` struct has two main methods: `PopulateDependancies` and `FetchConfig`. The `PopulateDependancies` is used to dynamically locate and set the config fields for each new sub-server. As the config may not actually have any fields (if the build flag is off), we use the reflect pacakge to determine if things are compiled in or not, then if so, we dynamically set each of the config parameters. The `PopulateDependancies` method implements the `lnrpc.SubServerConfigDispatcher` interface. Our goal is to allow sub servers to look up their actual config in this main config struct. We achieve this by using reflect to look up the target field _as if it were a key in a map_. If the field is found, then we check if it has any actual attributes (it won't if the build flag is off), if it is, then we return it as we expect it to be populated already.
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package main
import (
"fmt"
"reflect"
"github.com/btcsuite/btcd/chaincfg"
"github.com/lightningnetwork/lnd/autopilot"
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"github.com/lightningnetwork/lnd/channeldb"
"github.com/lightningnetwork/lnd/htlcswitch"
"github.com/lightningnetwork/lnd/invoices"
"github.com/lightningnetwork/lnd/lnrpc/autopilotrpc"
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"github.com/lightningnetwork/lnd/lnrpc/chainrpc"
"github.com/lightningnetwork/lnd/lnrpc/invoicesrpc"
"github.com/lightningnetwork/lnd/lnrpc/routerrpc"
config+rpc: create new generalized dynamic sub rpc server config framework In this commit, we add the glue infrastructure to make the sub RPC server system work properly. Our high level goal is the following: using only the lnrpc package (with no visibility into the sub RPC servers), the RPC server is able to find, create, run, and manage the entire set of present and future sub RPC servers. In order to achieve this, we use the reflect package and build tags heavily to permit a loosely coupled configuration parsing system for the sub RPC servers. We start with a new `subRpcServerConfigs` struct which is _always_ present. This struct has its own group, and will house a series of sub-configs, one for each sub RPC server. Each sub-config is actually gated behind a build flag, and can be used to allow users on the command line or in the config to specify arguments related to the sub-server. If the config isn't present, then we don't attempt to parse it at all, if it is, then that means the RPC server has been registered, and we should parse the contents of its config. The `subRpcServerConfigs` struct has two main methods: `PopulateDependancies` and `FetchConfig`. The `PopulateDependancies` is used to dynamically locate and set the config fields for each new sub-server. As the config may not actually have any fields (if the build flag is off), we use the reflect pacakge to determine if things are compiled in or not, then if so, we dynamically set each of the config parameters. The `PopulateDependancies` method implements the `lnrpc.SubServerConfigDispatcher` interface. Our goal is to allow sub servers to look up their actual config in this main config struct. We achieve this by using reflect to look up the target field _as if it were a key in a map_. If the field is found, then we check if it has any actual attributes (it won't if the build flag is off), if it is, then we return it as we expect it to be populated already.
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"github.com/lightningnetwork/lnd/lnrpc/signrpc"
"github.com/lightningnetwork/lnd/lnrpc/walletrpc"
config+rpc: create new generalized dynamic sub rpc server config framework In this commit, we add the glue infrastructure to make the sub RPC server system work properly. Our high level goal is the following: using only the lnrpc package (with no visibility into the sub RPC servers), the RPC server is able to find, create, run, and manage the entire set of present and future sub RPC servers. In order to achieve this, we use the reflect package and build tags heavily to permit a loosely coupled configuration parsing system for the sub RPC servers. We start with a new `subRpcServerConfigs` struct which is _always_ present. This struct has its own group, and will house a series of sub-configs, one for each sub RPC server. Each sub-config is actually gated behind a build flag, and can be used to allow users on the command line or in the config to specify arguments related to the sub-server. If the config isn't present, then we don't attempt to parse it at all, if it is, then that means the RPC server has been registered, and we should parse the contents of its config. The `subRpcServerConfigs` struct has two main methods: `PopulateDependancies` and `FetchConfig`. The `PopulateDependancies` is used to dynamically locate and set the config fields for each new sub-server. As the config may not actually have any fields (if the build flag is off), we use the reflect pacakge to determine if things are compiled in or not, then if so, we dynamically set each of the config parameters. The `PopulateDependancies` method implements the `lnrpc.SubServerConfigDispatcher` interface. Our goal is to allow sub servers to look up their actual config in this main config struct. We achieve this by using reflect to look up the target field _as if it were a key in a map_. If the field is found, then we check if it has any actual attributes (it won't if the build flag is off), if it is, then we return it as we expect it to be populated already.
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"github.com/lightningnetwork/lnd/macaroons"
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"github.com/lightningnetwork/lnd/netann"
"github.com/lightningnetwork/lnd/routing"
config+rpc: create new generalized dynamic sub rpc server config framework In this commit, we add the glue infrastructure to make the sub RPC server system work properly. Our high level goal is the following: using only the lnrpc package (with no visibility into the sub RPC servers), the RPC server is able to find, create, run, and manage the entire set of present and future sub RPC servers. In order to achieve this, we use the reflect package and build tags heavily to permit a loosely coupled configuration parsing system for the sub RPC servers. We start with a new `subRpcServerConfigs` struct which is _always_ present. This struct has its own group, and will house a series of sub-configs, one for each sub RPC server. Each sub-config is actually gated behind a build flag, and can be used to allow users on the command line or in the config to specify arguments related to the sub-server. If the config isn't present, then we don't attempt to parse it at all, if it is, then that means the RPC server has been registered, and we should parse the contents of its config. The `subRpcServerConfigs` struct has two main methods: `PopulateDependancies` and `FetchConfig`. The `PopulateDependancies` is used to dynamically locate and set the config fields for each new sub-server. As the config may not actually have any fields (if the build flag is off), we use the reflect pacakge to determine if things are compiled in or not, then if so, we dynamically set each of the config parameters. The `PopulateDependancies` method implements the `lnrpc.SubServerConfigDispatcher` interface. Our goal is to allow sub servers to look up their actual config in this main config struct. We achieve this by using reflect to look up the target field _as if it were a key in a map_. If the field is found, then we check if it has any actual attributes (it won't if the build flag is off), if it is, then we return it as we expect it to be populated already.
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)
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// subRPCServerConfigs is special sub-config in the main configuration that
config+rpc: create new generalized dynamic sub rpc server config framework In this commit, we add the glue infrastructure to make the sub RPC server system work properly. Our high level goal is the following: using only the lnrpc package (with no visibility into the sub RPC servers), the RPC server is able to find, create, run, and manage the entire set of present and future sub RPC servers. In order to achieve this, we use the reflect package and build tags heavily to permit a loosely coupled configuration parsing system for the sub RPC servers. We start with a new `subRpcServerConfigs` struct which is _always_ present. This struct has its own group, and will house a series of sub-configs, one for each sub RPC server. Each sub-config is actually gated behind a build flag, and can be used to allow users on the command line or in the config to specify arguments related to the sub-server. If the config isn't present, then we don't attempt to parse it at all, if it is, then that means the RPC server has been registered, and we should parse the contents of its config. The `subRpcServerConfigs` struct has two main methods: `PopulateDependancies` and `FetchConfig`. The `PopulateDependancies` is used to dynamically locate and set the config fields for each new sub-server. As the config may not actually have any fields (if the build flag is off), we use the reflect pacakge to determine if things are compiled in or not, then if so, we dynamically set each of the config parameters. The `PopulateDependancies` method implements the `lnrpc.SubServerConfigDispatcher` interface. Our goal is to allow sub servers to look up their actual config in this main config struct. We achieve this by using reflect to look up the target field _as if it were a key in a map_. If the field is found, then we check if it has any actual attributes (it won't if the build flag is off), if it is, then we return it as we expect it to be populated already.
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// houses the configuration for the optional sub-servers. These sub-RPC servers
// are meant to house experimental new features that may eventually make it
// into the main RPC server that lnd exposes. Special methods are present on
// this struct to allow the main RPC server to create and manipulate the
// sub-RPC servers in a generalized manner.
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type subRPCServerConfigs struct {
config+rpc: create new generalized dynamic sub rpc server config framework In this commit, we add the glue infrastructure to make the sub RPC server system work properly. Our high level goal is the following: using only the lnrpc package (with no visibility into the sub RPC servers), the RPC server is able to find, create, run, and manage the entire set of present and future sub RPC servers. In order to achieve this, we use the reflect package and build tags heavily to permit a loosely coupled configuration parsing system for the sub RPC servers. We start with a new `subRpcServerConfigs` struct which is _always_ present. This struct has its own group, and will house a series of sub-configs, one for each sub RPC server. Each sub-config is actually gated behind a build flag, and can be used to allow users on the command line or in the config to specify arguments related to the sub-server. If the config isn't present, then we don't attempt to parse it at all, if it is, then that means the RPC server has been registered, and we should parse the contents of its config. The `subRpcServerConfigs` struct has two main methods: `PopulateDependancies` and `FetchConfig`. The `PopulateDependancies` is used to dynamically locate and set the config fields for each new sub-server. As the config may not actually have any fields (if the build flag is off), we use the reflect pacakge to determine if things are compiled in or not, then if so, we dynamically set each of the config parameters. The `PopulateDependancies` method implements the `lnrpc.SubServerConfigDispatcher` interface. Our goal is to allow sub servers to look up their actual config in this main config struct. We achieve this by using reflect to look up the target field _as if it were a key in a map_. If the field is found, then we check if it has any actual attributes (it won't if the build flag is off), if it is, then we return it as we expect it to be populated already.
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// SignRPC is a sub-RPC server that exposes signing of arbitrary inputs
// as a gRPC service.
SignRPC *signrpc.Config `group:"signrpc" namespace:"signrpc"`
// WalletKitRPC is a sub-RPC server that exposes functionality allowing
// a client to send transactions through a wallet, publish them, and
// also requests keys and addresses under control of the backing
// wallet.
WalletKitRPC *walletrpc.Config `group:"walletrpc" namespace:"walletrpc"`
// AutopilotRPC is a sub-RPC server that exposes methods on the running
// autopilot as a gRPC service.
AutopilotRPC *autopilotrpc.Config `group:"autopilotrpc" namespace:"autopilotrpc"`
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// ChainRPC is a sub-RPC server that exposes functionality allowing a
// client to be notified of certain on-chain events (new blocks,
// confirmations, spends).
ChainRPC *chainrpc.Config `group:"chainrpc" namespace:"chainrpc"`
// InvoicesRPC is a sub-RPC server that exposes invoice related methods
// as a gRPC service.
InvoicesRPC *invoicesrpc.Config `group:"invoicesrpc" namespace:"invoicesrpc"`
// RouterRPC is a sub-RPC server the exposes functionality that allows
// clients to send payments on the network, and perform Lightning
// payment related queries such as requests for estimates of off-chain
// fees.
RouterRPC *routerrpc.Config `group:"routerrpc" namespace:"routerrpc"`
config+rpc: create new generalized dynamic sub rpc server config framework In this commit, we add the glue infrastructure to make the sub RPC server system work properly. Our high level goal is the following: using only the lnrpc package (with no visibility into the sub RPC servers), the RPC server is able to find, create, run, and manage the entire set of present and future sub RPC servers. In order to achieve this, we use the reflect package and build tags heavily to permit a loosely coupled configuration parsing system for the sub RPC servers. We start with a new `subRpcServerConfigs` struct which is _always_ present. This struct has its own group, and will house a series of sub-configs, one for each sub RPC server. Each sub-config is actually gated behind a build flag, and can be used to allow users on the command line or in the config to specify arguments related to the sub-server. If the config isn't present, then we don't attempt to parse it at all, if it is, then that means the RPC server has been registered, and we should parse the contents of its config. The `subRpcServerConfigs` struct has two main methods: `PopulateDependancies` and `FetchConfig`. The `PopulateDependancies` is used to dynamically locate and set the config fields for each new sub-server. As the config may not actually have any fields (if the build flag is off), we use the reflect pacakge to determine if things are compiled in or not, then if so, we dynamically set each of the config parameters. The `PopulateDependancies` method implements the `lnrpc.SubServerConfigDispatcher` interface. Our goal is to allow sub servers to look up their actual config in this main config struct. We achieve this by using reflect to look up the target field _as if it were a key in a map_. If the field is found, then we check if it has any actual attributes (it won't if the build flag is off), if it is, then we return it as we expect it to be populated already.
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}
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// PopulateDependencies attempts to iterate through all the sub-server configs
config+rpc: create new generalized dynamic sub rpc server config framework In this commit, we add the glue infrastructure to make the sub RPC server system work properly. Our high level goal is the following: using only the lnrpc package (with no visibility into the sub RPC servers), the RPC server is able to find, create, run, and manage the entire set of present and future sub RPC servers. In order to achieve this, we use the reflect package and build tags heavily to permit a loosely coupled configuration parsing system for the sub RPC servers. We start with a new `subRpcServerConfigs` struct which is _always_ present. This struct has its own group, and will house a series of sub-configs, one for each sub RPC server. Each sub-config is actually gated behind a build flag, and can be used to allow users on the command line or in the config to specify arguments related to the sub-server. If the config isn't present, then we don't attempt to parse it at all, if it is, then that means the RPC server has been registered, and we should parse the contents of its config. The `subRpcServerConfigs` struct has two main methods: `PopulateDependancies` and `FetchConfig`. The `PopulateDependancies` is used to dynamically locate and set the config fields for each new sub-server. As the config may not actually have any fields (if the build flag is off), we use the reflect pacakge to determine if things are compiled in or not, then if so, we dynamically set each of the config parameters. The `PopulateDependancies` method implements the `lnrpc.SubServerConfigDispatcher` interface. Our goal is to allow sub servers to look up their actual config in this main config struct. We achieve this by using reflect to look up the target field _as if it were a key in a map_. If the field is found, then we check if it has any actual attributes (it won't if the build flag is off), if it is, then we return it as we expect it to be populated already.
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// within this struct, and populate the items it requires based on the main
// configuration file, and the chain control.
//
// NOTE: This MUST be called before any callers are permitted to execute the
// FetchConfig method.
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func (s *subRPCServerConfigs) PopulateDependencies(cc *chainControl,
networkDir string, macService *macaroons.Service,
atpl *autopilot.Manager,
invoiceRegistry *invoices.InvoiceRegistry,
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htlcSwitch *htlcswitch.Switch,
activeNetParams *chaincfg.Params,
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chanRouter *routing.ChannelRouter,
nodeSigner *netann.NodeSigner,
chanDB *channeldb.DB) error {
config+rpc: create new generalized dynamic sub rpc server config framework In this commit, we add the glue infrastructure to make the sub RPC server system work properly. Our high level goal is the following: using only the lnrpc package (with no visibility into the sub RPC servers), the RPC server is able to find, create, run, and manage the entire set of present and future sub RPC servers. In order to achieve this, we use the reflect package and build tags heavily to permit a loosely coupled configuration parsing system for the sub RPC servers. We start with a new `subRpcServerConfigs` struct which is _always_ present. This struct has its own group, and will house a series of sub-configs, one for each sub RPC server. Each sub-config is actually gated behind a build flag, and can be used to allow users on the command line or in the config to specify arguments related to the sub-server. If the config isn't present, then we don't attempt to parse it at all, if it is, then that means the RPC server has been registered, and we should parse the contents of its config. The `subRpcServerConfigs` struct has two main methods: `PopulateDependancies` and `FetchConfig`. The `PopulateDependancies` is used to dynamically locate and set the config fields for each new sub-server. As the config may not actually have any fields (if the build flag is off), we use the reflect pacakge to determine if things are compiled in or not, then if so, we dynamically set each of the config parameters. The `PopulateDependancies` method implements the `lnrpc.SubServerConfigDispatcher` interface. Our goal is to allow sub servers to look up their actual config in this main config struct. We achieve this by using reflect to look up the target field _as if it were a key in a map_. If the field is found, then we check if it has any actual attributes (it won't if the build flag is off), if it is, then we return it as we expect it to be populated already.
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// First, we'll use reflect to obtain a version of the config struct
// that allows us to programmatically inspect its fields.
selfVal := extractReflectValue(s)
selfType := selfVal.Type()
numFields := selfVal.NumField()
for i := 0; i < numFields; i++ {
field := selfVal.Field(i)
fieldElem := field.Elem()
fieldName := selfType.Field(i).Name
ltndLog.Debugf("Populating dependencies for sub RPC "+
"server: %v", fieldName)
// If this sub-config doesn't actually have any fields, then we
// can skip it, as the build tag for it is likely off.
if fieldElem.NumField() == 0 {
continue
}
if !fieldElem.CanSet() {
continue
}
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switch subCfg := field.Interface().(type) {
config+rpc: create new generalized dynamic sub rpc server config framework In this commit, we add the glue infrastructure to make the sub RPC server system work properly. Our high level goal is the following: using only the lnrpc package (with no visibility into the sub RPC servers), the RPC server is able to find, create, run, and manage the entire set of present and future sub RPC servers. In order to achieve this, we use the reflect package and build tags heavily to permit a loosely coupled configuration parsing system for the sub RPC servers. We start with a new `subRpcServerConfigs` struct which is _always_ present. This struct has its own group, and will house a series of sub-configs, one for each sub RPC server. Each sub-config is actually gated behind a build flag, and can be used to allow users on the command line or in the config to specify arguments related to the sub-server. If the config isn't present, then we don't attempt to parse it at all, if it is, then that means the RPC server has been registered, and we should parse the contents of its config. The `subRpcServerConfigs` struct has two main methods: `PopulateDependancies` and `FetchConfig`. The `PopulateDependancies` is used to dynamically locate and set the config fields for each new sub-server. As the config may not actually have any fields (if the build flag is off), we use the reflect pacakge to determine if things are compiled in or not, then if so, we dynamically set each of the config parameters. The `PopulateDependancies` method implements the `lnrpc.SubServerConfigDispatcher` interface. Our goal is to allow sub servers to look up their actual config in this main config struct. We achieve this by using reflect to look up the target field _as if it were a key in a map_. If the field is found, then we check if it has any actual attributes (it won't if the build flag is off), if it is, then we return it as we expect it to be populated already.
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case *signrpc.Config:
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subCfgValue := extractReflectValue(subCfg)
config+rpc: create new generalized dynamic sub rpc server config framework In this commit, we add the glue infrastructure to make the sub RPC server system work properly. Our high level goal is the following: using only the lnrpc package (with no visibility into the sub RPC servers), the RPC server is able to find, create, run, and manage the entire set of present and future sub RPC servers. In order to achieve this, we use the reflect package and build tags heavily to permit a loosely coupled configuration parsing system for the sub RPC servers. We start with a new `subRpcServerConfigs` struct which is _always_ present. This struct has its own group, and will house a series of sub-configs, one for each sub RPC server. Each sub-config is actually gated behind a build flag, and can be used to allow users on the command line or in the config to specify arguments related to the sub-server. If the config isn't present, then we don't attempt to parse it at all, if it is, then that means the RPC server has been registered, and we should parse the contents of its config. The `subRpcServerConfigs` struct has two main methods: `PopulateDependancies` and `FetchConfig`. The `PopulateDependancies` is used to dynamically locate and set the config fields for each new sub-server. As the config may not actually have any fields (if the build flag is off), we use the reflect pacakge to determine if things are compiled in or not, then if so, we dynamically set each of the config parameters. The `PopulateDependancies` method implements the `lnrpc.SubServerConfigDispatcher` interface. Our goal is to allow sub servers to look up their actual config in this main config struct. We achieve this by using reflect to look up the target field _as if it were a key in a map_. If the field is found, then we check if it has any actual attributes (it won't if the build flag is off), if it is, then we return it as we expect it to be populated already.
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subCfgValue.FieldByName("MacService").Set(
reflect.ValueOf(macService),
)
subCfgValue.FieldByName("NetworkDir").Set(
reflect.ValueOf(networkDir),
)
subCfgValue.FieldByName("Signer").Set(
reflect.ValueOf(cc.signer),
)
case *walletrpc.Config:
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subCfgValue := extractReflectValue(subCfg)
subCfgValue.FieldByName("NetworkDir").Set(
reflect.ValueOf(networkDir),
)
subCfgValue.FieldByName("MacService").Set(
reflect.ValueOf(macService),
)
subCfgValue.FieldByName("FeeEstimator").Set(
reflect.ValueOf(cc.feeEstimator),
)
subCfgValue.FieldByName("Wallet").Set(
reflect.ValueOf(cc.wallet),
)
subCfgValue.FieldByName("KeyRing").Set(
reflect.ValueOf(cc.keyRing),
)
case *autopilotrpc.Config:
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subCfgValue := extractReflectValue(subCfg)
subCfgValue.FieldByName("Manager").Set(
reflect.ValueOf(atpl),
)
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case *chainrpc.Config:
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subCfgValue := extractReflectValue(subCfg)
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subCfgValue.FieldByName("NetworkDir").Set(
reflect.ValueOf(networkDir),
)
subCfgValue.FieldByName("MacService").Set(
reflect.ValueOf(macService),
)
subCfgValue.FieldByName("ChainNotifier").Set(
reflect.ValueOf(cc.chainNotifier),
)
case *invoicesrpc.Config:
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subCfgValue := extractReflectValue(subCfg)
subCfgValue.FieldByName("NetworkDir").Set(
reflect.ValueOf(networkDir),
)
subCfgValue.FieldByName("MacService").Set(
reflect.ValueOf(macService),
)
subCfgValue.FieldByName("InvoiceRegistry").Set(
reflect.ValueOf(invoiceRegistry),
)
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subCfgValue.FieldByName("IsChannelActive").Set(
reflect.ValueOf(htlcSwitch.HasActiveLink),
)
subCfgValue.FieldByName("ChainParams").Set(
reflect.ValueOf(activeNetParams),
)
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subCfgValue.FieldByName("NodeSigner").Set(
reflect.ValueOf(nodeSigner),
)
subCfgValue.FieldByName("MaxPaymentMSat").Set(
reflect.ValueOf(maxPaymentMSat),
)
defaultDelta := cfg.Bitcoin.TimeLockDelta
if registeredChains.PrimaryChain() == litecoinChain {
defaultDelta = cfg.Litecoin.TimeLockDelta
}
subCfgValue.FieldByName("DefaultCLTVExpiry").Set(
reflect.ValueOf(defaultDelta),
)
subCfgValue.FieldByName("ChanDB").Set(
reflect.ValueOf(chanDB),
)
case *routerrpc.Config:
subCfgValue := extractReflectValue(cfg)
subCfgValue.FieldByName("NetworkDir").Set(
reflect.ValueOf(networkDir),
)
subCfgValue.FieldByName("ActiveNetParams").Set(
reflect.ValueOf(activeNetParams),
)
subCfgValue.FieldByName("MacService").Set(
reflect.ValueOf(macService),
)
subCfgValue.FieldByName("Router").Set(
reflect.ValueOf(chanRouter),
)
config+rpc: create new generalized dynamic sub rpc server config framework In this commit, we add the glue infrastructure to make the sub RPC server system work properly. Our high level goal is the following: using only the lnrpc package (with no visibility into the sub RPC servers), the RPC server is able to find, create, run, and manage the entire set of present and future sub RPC servers. In order to achieve this, we use the reflect package and build tags heavily to permit a loosely coupled configuration parsing system for the sub RPC servers. We start with a new `subRpcServerConfigs` struct which is _always_ present. This struct has its own group, and will house a series of sub-configs, one for each sub RPC server. Each sub-config is actually gated behind a build flag, and can be used to allow users on the command line or in the config to specify arguments related to the sub-server. If the config isn't present, then we don't attempt to parse it at all, if it is, then that means the RPC server has been registered, and we should parse the contents of its config. The `subRpcServerConfigs` struct has two main methods: `PopulateDependancies` and `FetchConfig`. The `PopulateDependancies` is used to dynamically locate and set the config fields for each new sub-server. As the config may not actually have any fields (if the build flag is off), we use the reflect pacakge to determine if things are compiled in or not, then if so, we dynamically set each of the config parameters. The `PopulateDependancies` method implements the `lnrpc.SubServerConfigDispatcher` interface. Our goal is to allow sub servers to look up their actual config in this main config struct. We achieve this by using reflect to look up the target field _as if it were a key in a map_. If the field is found, then we check if it has any actual attributes (it won't if the build flag is off), if it is, then we return it as we expect it to be populated already.
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default:
return fmt.Errorf("unknown field: %v, %T", fieldName,
cfg)
}
}
return nil
}
// FetchConfig attempts to locate an existing configuration file mapped to the
// target sub-server. If we're unable to find a config file matching the
// subServerName name, then false will be returned for the second parameter.
//
// NOTE: Part of the lnrpc.SubServerConfigDispatcher interface.
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func (s *subRPCServerConfigs) FetchConfig(subServerName string) (interface{}, bool) {
config+rpc: create new generalized dynamic sub rpc server config framework In this commit, we add the glue infrastructure to make the sub RPC server system work properly. Our high level goal is the following: using only the lnrpc package (with no visibility into the sub RPC servers), the RPC server is able to find, create, run, and manage the entire set of present and future sub RPC servers. In order to achieve this, we use the reflect package and build tags heavily to permit a loosely coupled configuration parsing system for the sub RPC servers. We start with a new `subRpcServerConfigs` struct which is _always_ present. This struct has its own group, and will house a series of sub-configs, one for each sub RPC server. Each sub-config is actually gated behind a build flag, and can be used to allow users on the command line or in the config to specify arguments related to the sub-server. If the config isn't present, then we don't attempt to parse it at all, if it is, then that means the RPC server has been registered, and we should parse the contents of its config. The `subRpcServerConfigs` struct has two main methods: `PopulateDependancies` and `FetchConfig`. The `PopulateDependancies` is used to dynamically locate and set the config fields for each new sub-server. As the config may not actually have any fields (if the build flag is off), we use the reflect pacakge to determine if things are compiled in or not, then if so, we dynamically set each of the config parameters. The `PopulateDependancies` method implements the `lnrpc.SubServerConfigDispatcher` interface. Our goal is to allow sub servers to look up their actual config in this main config struct. We achieve this by using reflect to look up the target field _as if it were a key in a map_. If the field is found, then we check if it has any actual attributes (it won't if the build flag is off), if it is, then we return it as we expect it to be populated already.
2018-10-23 03:58:30 +03:00
// First, we'll use reflect to obtain a version of the config struct
// that allows us to programmatically inspect its fields.
selfVal := extractReflectValue(s)
// Now that we have the value of the struct, we can check to see if it
// has an attribute with the same name as the subServerName.
configVal := selfVal.FieldByName(subServerName)
// We'll now ensure that this field actually exists in this value. If
// not, then we'll return false for the ok value to indicate to the
// caller that this field doesn't actually exist.
if !configVal.IsValid() {
return nil, false
}
configValElem := configVal.Elem()
config+rpc: create new generalized dynamic sub rpc server config framework In this commit, we add the glue infrastructure to make the sub RPC server system work properly. Our high level goal is the following: using only the lnrpc package (with no visibility into the sub RPC servers), the RPC server is able to find, create, run, and manage the entire set of present and future sub RPC servers. In order to achieve this, we use the reflect package and build tags heavily to permit a loosely coupled configuration parsing system for the sub RPC servers. We start with a new `subRpcServerConfigs` struct which is _always_ present. This struct has its own group, and will house a series of sub-configs, one for each sub RPC server. Each sub-config is actually gated behind a build flag, and can be used to allow users on the command line or in the config to specify arguments related to the sub-server. If the config isn't present, then we don't attempt to parse it at all, if it is, then that means the RPC server has been registered, and we should parse the contents of its config. The `subRpcServerConfigs` struct has two main methods: `PopulateDependancies` and `FetchConfig`. The `PopulateDependancies` is used to dynamically locate and set the config fields for each new sub-server. As the config may not actually have any fields (if the build flag is off), we use the reflect pacakge to determine if things are compiled in or not, then if so, we dynamically set each of the config parameters. The `PopulateDependancies` method implements the `lnrpc.SubServerConfigDispatcher` interface. Our goal is to allow sub servers to look up their actual config in this main config struct. We achieve this by using reflect to look up the target field _as if it were a key in a map_. If the field is found, then we check if it has any actual attributes (it won't if the build flag is off), if it is, then we return it as we expect it to be populated already.
2018-10-23 03:58:30 +03:00
// If a config of this type is found, it doesn't have any fields, then
// it's the same as if it wasn't present. This can happen if the build
// tag for the sub-server is inactive.
if configValElem.NumField() == 0 {
return nil, false
}
// At this pint, we know that the field is actually present in the
// config struct, so we can return it directly.
return configVal.Interface(), true
}
// extractReflectValue attempts to extract the value from an interface using
// the reflect package. The resulting reflect.Value allows the caller to
// programmatically examine and manipulate the underlying value.
func extractReflectValue(instance interface{}) reflect.Value {
var val reflect.Value
// If the type of the instance is a pointer, then we need to deference
// the pointer one level to get its value. Otherwise, we can access the
// value directly.
if reflect.TypeOf(instance).Kind() == reflect.Ptr {
val = reflect.ValueOf(instance).Elem()
} else {
val = reflect.ValueOf(instance)
}
return val
}