dgraph_txn.go

package agora

import (
	"encoding/json"
	"log"
	"time"

	"github.com/brianbroderick/logit"
	"github.com/dgraph-io/dgo/v210/protos/api"
)

// MutateDgraph is a helper func to run Mutate operations on Dgraph
func MutateDgraph(jsonStr []byte) *api.Response {
	c := NewDgraphTxn()
	defer c.DiscardTxn()

	mu := &api.Mutation{
		CommitNow: true,
		SetJson:   jsonStr,
	}

	assigned, err := c.Txn.Mutate(c.Ctx, mu)
	if err != nil {
		logit.Fatal(" %e", err)
	}
	return assigned
}

// DeleteDgraph is a helper func to run Mutate operations on Dgraph
func DeleteDgraph(jsonStr []byte) *api.Response {
	c := NewDgraphTxn()
	defer c.DiscardTxn()

	mu := &api.Mutation{
		CommitNow:  true,
		DeleteJson: jsonStr,
	}

	assigned, err := c.Txn.Mutate(c.Ctx, mu)
	if err != nil {
		logit.Fatal(" %e", err)
	}
	return assigned
}

// QueryDgraph runs a query operation on DGraph and returns the JSON response
func QueryDgraph(query string) []byte {
	c := NewDgraphTxn()
	defer c.DiscardTxn()

	resp, err := c.Txn.Query(c.Ctx, query)
	if err != nil {
		return RetryQueryDgraph(query, 1)
	}

	return resp.Json
}

// RetryQueryDgraph retries the query. This is so dgraph has time to boot up in Docker.
func RetryQueryDgraph(query string, attempt int) []byte {
	logit.Warn("Retrying Query")
	time.Sleep(500 * time.Millisecond)

	c := NewDgraphTxn()
	defer c.DiscardTxn()

	resp, err := c.Txn.Query(c.Ctx, query)
	if err != nil {
		if attempt > 20 {
			return RetryQueryDgraph(query, attempt+1)
		} else {
			logit.Warn("Query Error: %e.", err)
			logit.Warn("Retried too many times. Not trying again.")
			return []byte{}
		}
	}

	return resp.Json
}

// QueryDgraphWithVars runs a query operation on DGraph with variables and returns the JSON response
func QueryDgraphWithVars(query string, variables map[string]string) []byte {
	c := NewDgraphTxn()
	defer c.DiscardTxn()

	resp, err := c.Txn.QueryWithVars(c.Ctx, query, variables)
	if err != nil {
		return RetryQueryDgraphWithVars(query, variables, 1)
	}

	return resp.Json
}

// RetryQueryDgraphWithVars retries a query on DGraph with variables and returns the JSON response
func RetryQueryDgraphWithVars(query string, variables map[string]string, attempt int) []byte {
	logit.Warn("Retrying Query")
	time.Sleep(500 * time.Millisecond)

	c := NewDgraphTxn()
	defer c.DiscardTxn()

	resp, err := c.Txn.QueryWithVars(c.Ctx, query, variables)
	if err != nil {
		if attempt > 20 {
			return RetryQueryDgraphWithVars(query, variables, attempt+1)
		} else {
			logit.Warn("Query Error: %e.", err)
			logit.Warn("Retried too many times. Not trying again.")
			return []byte{}
		}
	}

	return resp.Json
}

func ResolveQuery(r interface{}, query string) error {
	j := QueryDgraph(query)

	err := json.Unmarshal(j, &r)
	if err != nil {
		return err
	}

	return nil
}

func ResolveQueryWithVars(r interface{}, query string, variables map[string]string) error {
	j := QueryDgraphWithVars(query, variables)

	err := json.Unmarshal(j, &r)
	if err != nil {
		return err
	}

	return nil
}

// AlterDgraph runs an alter Dgraph operation
func AlterDgraph(op *api.Operation) {
	c := NewDgraphTxn()
	defer c.DiscardTxn()

	err := c.Dg.Alter(c.Ctx, op)
	if err != nil {
		log.Fatal(err)
	}
}

// This isn't working with vars. Need to fix

// UpsertDgraph is a helper func to run Upsert operations on Dgraph
// func UpsertDgraph(query string, variables map[string]string, cond string, jsonStr []byte) []byte {
// 	c := NewDgraphTxn()
// 	defer c.DiscardTxn()

// 	mu := &api.Mutation{
// 		SetJson: jsonStr,
// 	}
// 	// if cond != "" {
// 	// 	mu.Cond = cond
// 	// }

// 	req := &api.Request{
// 		Query:     query,
// 		Vars:      variables,
// 		Mutations: []*api.Mutation{mu},
// 		CommitNow: true,
// 	}

// 	// // Update email only if matching uid found.
// 	resp, err := c.Txn.Do(c.Ctx, req)
// 	if err != nil {
// 		logit.Fatal(" Query Error: %e", err)
// 	}
// 	return resp.Json
// }