loop: add get and set parameters endpoints

Add the ability to get and set our liquidity paramters to the cli. A
separate rule command is added to keep the cli simple.

cmd/loop/liquidity.go

@@ -0,0 +1,172 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+
+	"github.com/lightninglabs/loop/looprpc"
+	"github.com/urfave/cli"
+)
+
+var getLiquidityParamsCommand = cli.Command{
+	Name:  "getparams",
+	Usage: "show liquidity manager parameters",
+	Description: "Displays the current set of parameters that are set " +
+		"for the liquidity manager.",
+	Action: getParams,
+}
+
+func getParams(ctx *cli.Context) error {
+	client, cleanup, err := getClient(ctx)
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	cfg, err := client.GetLiquidityParams(
+		context.Background(), &looprpc.GetLiquidityParamsRequest{},
+	)
+	if err != nil {
+		return err
+	}
+
+	printRespJSON(cfg)
+
+	return nil
+}
+
+var setLiquidityParamCommand = cli.Command{
+	Name:        "setparam",
+	Usage:       "set liquidity manager rule for a channel",
+	Description: "Update or remove the liquidity rule for a channel.",
+	ArgsUsage:   "shortchanid",
+	Flags: []cli.Flag{
+		cli.IntFlag{
+			Name: "incoming_threshold",
+			Usage: "the minimum percentage of incoming liquidity " +
+				"to total capacity beneath which to " +
+				"recommend loop out to acquire incoming.",
+		},
+		cli.IntFlag{
+			Name: "outgoing_threshold",
+			Usage: "the minimum percentage of outbound liquidity " +
+				"that we do not want to drop below.",
+		},
+		cli.BoolFlag{
+			Name:  "clear",
+			Usage: "remove the rule currently set for the channel.",
+		},
+	},
+	Action: setParam,
+}
+
+func setParam(ctx *cli.Context) error {
+	// We require that a channel ID is set for this rule update.
+	if ctx.NArg() != 1 {
+		return fmt.Errorf("please set a channel id for the rule " +
+			"update")
+	}
+
+	chanID, err := strconv.ParseUint(ctx.Args().First(), 10, 64)
+	if err != nil {
+		return fmt.Errorf("could not parse channel ID: %v", err)
+	}
+
+	client, cleanup, err := getClient(ctx)
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	// We need to set the full set of current parameters every time we call
+	// SetParameters. To allow users to set only individual fields on the
+	// cli, we lookup our current params, then update individual values.
+	params, err := client.GetLiquidityParams(
+		context.Background(), &looprpc.GetLiquidityParamsRequest{},
+	)
+	if err != nil {
+		return err
+	}
+
+	var (
+		inboundSet  = ctx.IsSet("incoming_threshold")
+		outboundSet = ctx.IsSet("outgoing_threshold")
+		ruleSet     bool
+		otherRules  []*looprpc.LiquidityRule
+	)
+
+	// Run through our current set of rules and check whether we have a rule
+	// currently set for this channel. We also track a slice containing all
+	// of the rules we currently have set for other channels, because we
+	// want to leave these rules untouched.
+	for _, rule := range params.Rules {
+		if rule.ChannelId == chanID {
+			ruleSet = true
+		} else {
+			otherRules = append(otherRules, rule)
+		}
+	}
+
+	// If we want to clear the rule for this channel, check that we had a
+	// rule set in the first place, and set our parameters to the current
+	// set excluding the channel specified.
+	if ctx.IsSet("clear") {
+		if !ruleSet {
+			return fmt.Errorf("cannot clear channel: %v, no rule "+
+				"set at present", chanID)
+		}
+
+		if inboundSet || outboundSet {
+			return fmt.Errorf("do not set other flags with clear " +
+				"flag")
+		}
+
+		_, err = client.SetLiquidityParams(
+			context.Background(),
+			&looprpc.SetLiquidityParamsRequest{
+				Parameters: &looprpc.LiquidityParameters{
+					Rules: otherRules,
+				},
+			},
+		)
+		return err
+	}
+
+	// If we are setting a rule for this channel (not clearing it), check
+	// that at least one value is set.
+	if !inboundSet && !outboundSet {
+		return fmt.Errorf("provide at least one flag to set rules or " +
+			"use the --clear flag to remove rules")
+	}
+
+	// Create a new rule which will be used to overwrite our current rule.
+	newRule := &looprpc.LiquidityRule{
+		ChannelId: chanID,
+		Type:      looprpc.LiquidityRuleType_THRESHOLD,
+	}
+
+	if inboundSet {
+		newRule.IncomingThreshold = uint32(
+			ctx.Int("incoming_threshold"),
+		)
+	}
+
+	if outboundSet {
+		newRule.OutgoingThreshold = uint32(
+			ctx.Int("outgoing_threshold"),
+		)
+	}
+
+	// Update our parameters to the existing set, plus our new rule.
+	_, err = client.SetLiquidityParams(
+		context.Background(),
+		&looprpc.SetLiquidityParamsRequest{
+			Parameters: &looprpc.LiquidityParameters{
+				Rules: append(otherRules, newRule),
+			},
+		},
+	)
+
+	return err
+}

cmd/loop/main.go

@@ -109,7 +109,8 @@ func main() {
 	app.Commands = []cli.Command{
 		loopOutCommand, loopInCommand, termsCommand,
 		monitorCommand, quoteCommand, listAuthCommand,
-		listSwapsCommand, swapInfoCommand,
+		listSwapsCommand, swapInfoCommand, getLiquidityParamsCommand,
+		setLiquidityParamCommand,
 	}
 
 	err := app.Run(os.Args)