neo4j-driver-go-skill

When to Use

• Writing Go code that connects to Neo4j
• Setting up neo4j.NewDriver(), ExecuteQuery(), or session/transaction patterns
• Debugging connection errors, result iteration, type assertions, causal consistency

When NOT to Use

• Writing/optimizing Cypher → neo4j-cypher-skill
• v5→v6 migration steps → neo4j-migration-skill

---

Installation

go get github.com/neo4j/neo4j-go-driver/v6

Import: github.com/neo4j/neo4j-go-driver/v6/neo4j

v5→v6 rename (deprecated aliases still compile, remove before v7):

v5	v6
neo4j.NewDriverWithContext(...)	neo4j.NewDriver(...)
neo4j.DriverWithContext	neo4j.Driver

---

Environment Variables

import "os"

uri      := getEnv("NEO4J_URI",      "neo4j://localhost:7687")
user     := getEnv("NEO4J_USERNAME", "neo4j")
password := getEnv("NEO4J_PASSWORD", "")
database := getEnv("NEO4J_DATABASE", "neo4j")

func getEnv(key, fallback string) string {
    if v := os.Getenv(key); v != "" { return v }
    return fallback
}

Use godotenv to load .env in dev: godotenv.Load(). .env in .gitignore.

---

Driver Lifecycle

One Driver per application. Goroutine-safe, connection-pooled, expensive to create.

func NewNeo4jDriver(uri, user, password string) (neo4j.Driver, error) {
    driver, err := neo4j.NewDriver(
        uri, // "neo4j+s://xxx.databases.neo4j.io" for Aura
        neo4j.BasicAuth(user, password, ""),
    )
    if err != nil {
        return nil, fmt.Errorf("create driver: %w", err)
    }
    ctx := context.Background()
    if err := driver.VerifyConnectivity(ctx); err != nil {
        driver.Close(ctx)
        return nil, fmt.Errorf("verify connectivity: %w", err)
    }
    return driver, nil
}

// In main / app teardown:
defer driver.Close(ctx)

❌ Never create driver per-request. Create once at startup; share across goroutines.

URI schemes: neo4j+s:// (Aura/TLS+routing), neo4j:// (plain+routing), bolt+s:// (TLS+single), bolt:// (plain+single).

---

Choosing the Right API

API	Use when	Auto-retry	Lazy results
neo4j.ExecuteQuery()	Most queries — simple default	✅	❌ eager
session.ExecuteRead/Write()	Large result sets / streaming	✅	✅
session.BeginTransaction()	Spans multiple functions / ext coordination	❌	✅
session.Run()	CALL IN TRANSACTIONS / auto-commit only	❌	✅

CALL { … } IN TRANSACTIONS and USING PERIODIC COMMIT manage their own transactions — use session.Run(). They fail inside managed transactions.

---

ExecuteQuery (Recommended Default)

Manages sessions, transactions, retries, and bookmarks automatically.

result, err := neo4j.ExecuteQuery(ctx, driver,
    `MATCH (p:Person {name: $name})-[:KNOWS]->(friend)
     RETURN friend.name AS name`,
    map[string]any{"name": "Alice"},
    neo4j.EagerResultTransformer,
    neo4j.ExecuteQueryWithDatabase("neo4j"),       // always specify
    neo4j.ExecuteQueryWithReadersRouting(),         // for read queries
)
if err != nil {
    return fmt.Errorf("query people: %w", err)
}

for _, record := range result.Records {
    name, _ := record.Get("name")
    fmt.Println(name)
}
fmt.Println(result.Summary.Counters().NodesCreated())

Key options:

neo4j.ExecuteQueryWithDatabase("mydb")          // required for performance
neo4j.ExecuteQueryWithReadersRouting()           // route reads to replicas
neo4j.ExecuteQueryWithImpersonatedUser("jane")  // impersonate
neo4j.ExecuteQueryWithoutBookmarkManager()       // opt out of causal consistency

❌ Never concatenate user input into query strings. Always use map[string]any parameters.

---

Managed Transactions (Session-Based)

Use for lazy streaming (large result sets) or callback-level control.

session := driver.NewSession(ctx, neo4j.SessionConfig{
    DatabaseName: "neo4j", // always specify
    AccessMode:   neo4j.AccessModeRead,
})
defer session.Close(ctx)

result, err := session.ExecuteRead(ctx,
    func(tx neo4j.ManagedTransaction) (any, error) {
        res, err := tx.Run(ctx,
            `MATCH (p:Person) RETURN p.name AS name LIMIT $limit`,
            map[string]any{"limit": 100},
        )
        if err != nil {
            return nil, err
        }
        var names []string
        for res.Next(ctx) { // lazy — don't Collect() on large sets
            name, _ := res.Record().Get("name")
            names = append(names, name.(string))
        }
        return names, res.Err()
    },
)

❌ No side effects in callback — retried on transient failures. ExecuteRead → replicas. ExecuteWrite → cluster leader.

---

Explicit Transactions

Use when transaction work spans multiple functions or requires external coordination.

session := driver.NewSession(ctx, neo4j.SessionConfig{DatabaseName: "neo4j"})
defer session.Close(ctx)

tx, err := session.BeginTransaction(ctx)
if err != nil {
    return err
}
if err := doPartA(ctx, tx); err != nil {
    tx.Rollback(ctx)
    return err
}
if err := doPartB(ctx, tx); err != nil {
    tx.Rollback(ctx)
    return err
}
return tx.Commit(ctx)

❌ Not auto-retried. Caller handles retry. Prefer managed transactions unless you need explicit control.

---

Error Handling

result, err := neo4j.ExecuteQuery(...)
if err != nil {
    var neo4jErr *neo4j.Neo4jError
    if errors.As(err, &neo4jErr) {
        slog.Error("database error", "code", neo4jErr.Code, "msg", neo4jErr.Msg)
    }
    var connErr *neo4j.ConnectivityError
    if errors.As(err, &connErr) {
        slog.Error("connectivity error", "err", connErr)
    }
    return fmt.Errorf("execute query: %w", err)
}

Helpers:

neo4j.IsNeo4jError(err)                // server-side Cypher/database error
neo4j.IsTransactionExecutionLimit(err) // managed tx retries exhausted

In managed tx callback: return error → driver retries if transient. ConnectivityError at startup: check URI scheme, credentials, firewall.

---

Data Types

Cypher	Go
Integer	int64
Float	float64
String	string
Boolean	bool
List	[]any
Map	map[string]any
Node	neo4j.Node
Relationship	neo4j.Relationship
Path	neo4j.Path
Date	neo4j.Date
DateTime	neo4j.Time
Duration	neo4j.Duration
null	nil

// Typed extraction (v6+, preferred):
neo4j.GetRecordValue[string](record, "name")

// Manual extraction:
rawAge, ok := record.Get("age")
if !ok { return errors.New("missing 'age' field") }
age := rawAge.(int64) // Neo4j integers → int64

// Node access:
rawNode, _ := record.Get("p")
node := rawNode.(neo4j.Node)
name := node.Props["name"].(string)
labels := node.Labels // []string

❌ Always check ok from record.Get() before type-asserting — panics on missing key. ❌ After lazy for res.Next(ctx) loop, always check res.Err().

---

Key Patterns

Context — always propagate

ctx, cancel := context.WithTimeout(parentCtx, 5*time.Second)
defer cancel()
// pass ctx to all driver calls

context.Background() has no deadline — slow queries block indefinitely.

Batching Writes

// Bad: one transaction per record
for _, item := range items {
    neo4j.ExecuteQuery(ctx, driver, writeQuery, item, ...)
}

// Good: UNWIND batch in one transaction
neo4j.ExecuteQuery(ctx, driver,
    `UNWIND $items AS item
     MERGE (n:Node {id: item.id})
     SET n += item`,
    map[string]any{"items": items},
    neo4j.EagerResultTransformer,
    neo4j.ExecuteQueryWithDatabase("neo4j"),
)

Generic Helpers (v6+)

Prefer type-safe helpers over manual assertions:

// GetRecordValue[T] — extract + cast in one call
name, isNil, err := neo4j.GetRecordValue[string](record, "name")
// isNil=true when OPTIONAL MATCH returned null; err != nil when key absent or wrong type

// CollectTWithContext — map all records to a slice
people, err := neo4j.CollectTWithContext(ctx, result, func(record *neo4j.Record) (Person, error) {
    name, _, err := neo4j.GetRecordValue[string](record, "name")
    age, _, _   := neo4j.GetRecordValue[int64](record, "age")
    return Person{Name: name, Age: int(age)}, err
})

// SingleTWithContext — expect exactly one record (error if 0 or 2+)
person, err := neo4j.SingleTWithContext(ctx, result, func(record *neo4j.Record) (Person, error) {
    name, _, _ := neo4j.GetRecordValue[string](record, "name")
    return Person{Name: name}, nil
})

// GetProperty — typed property from Node or Relationship
node, _, _ := neo4j.GetRecordValue[neo4j.Node](record, "p")
nameVal, err := neo4j.GetProperty[string](node, "name")

Spatial Types

// 2D Cartesian (SRID 7203), 3D Cartesian (SRID 9157)
pt2d := neo4j.Point2D{X: 1.23, Y: 4.56, SpatialRefId: 7203}
pt3d := neo4j.Point3D{X: 1.23, Y: 4.56, Z: 7.89, SpatialRefId: 9157}

// 2D WGS-84 (SRID 4326), 3D WGS-84 (SRID 4979)
london := neo4j.Point2D{X: -0.118092, Y: 51.509865, SpatialRefId: 4326}
shard  := neo4j.Point3D{X: -0.0865, Y: 51.5045, Z: 310, SpatialRefId: 4979}

// Pass as parameter
result, err := neo4j.ExecuteQuery(ctx, driver,
    "CREATE (p:Place {location: $loc})",
    map[string]any{"loc": london},
    neo4j.EagerResultTransformer,
    neo4j.ExecuteQueryWithDatabase("neo4j"),
)

// Read from result — assert to Point2D or Point3D
raw, _ := record.Get("location")
if p2d, ok := raw.(neo4j.Point2D); ok {
    fmt.Printf("lon=%f lat=%f srid=%d\n", p2d.X, p2d.Y, p2d.SpatialRefId)
}

// Distance (same SRID only)
result, _ = neo4j.ExecuteQuery(ctx, driver,
    "RETURN point.distance($p1, $p2) AS distance",
    map[string]any{"p1": pt2d, "p2": neo4j.Point2D{X: 10, Y: 10, SpatialRefId: 7203}},
    neo4j.EagerResultTransformer, neo4j.ExecuteQueryWithDatabase("neo4j"),
)
dist, _ := result.Records[0].Get("distance")
fmt.Println(dist.(float64))

Always Specify Database

neo4j.ExecuteQueryWithDatabase("neo4j")    // in ExecuteQuery
neo4j.SessionConfig{DatabaseName: "neo4j"} // in sessions

Omitting costs a network round-trip per call to resolve home database.

Causal Consistency

ExecuteQuery manages bookmarks automatically — no action needed for sequential calls. Cross-session (parallel workers): combine bookmarks explicitly — see references/repository-pattern.md.

---

Common Errors

Error / Symptom	Cause	Fix
ConnectivityError at startup	URI wrong / TLS mismatch / firewall	Check scheme (neo4j+s:// for Aura), credentials, port 7687
ConnectivityError mid-run	Pool exhausted	Increase MaxConnectionPoolSize; check for leaked sessions
Panic on type assertion	record.Get() returned nil/wrong type	Use neo4j.GetRecordValue[T]() or check ok first
res.Err() non-nil after loop	Network error mid-stream	Handle error; re-run transaction
Callback retried unexpectedly	Side effect inside managed tx	Move side effects outside callback
Context deadline exceeded	No timeout on context	Use context.WithTimeout
0 results, query looks correct	Wrong DatabaseName	Always set DatabaseName in config
CALL IN TRANSACTIONS fails	Run inside managed tx	Use session.Run() (auto-commit)

---

References

Load on demand: Load on demand:

• references/advanced-config.md — connection pool tuning, custom address resolver, notification config, Bolt logging, auth options, URI scheme table
• references/repository-pattern.md — repository wrapper pattern, cross-session causal consistency with bookmarks

WebFetch

Need	URL
Go driver manual	https://neo4j.com/docs/go-manual/current/
API reference	https://pkg.go.dev/github.com/neo4j/neo4j-go-driver/v6/neo4j

---

Checklist

• One driver created at startup; shared across goroutines; defer driver.Close(ctx)
• driver.VerifyConnectivity(ctx) called at startup
• DatabaseName set in all SessionConfig / ExecuteQueryWithDatabase
• context.WithTimeout used for production queries
• map[string]any parameters used — no string interpolation
• ExecuteQueryWithReadersRouting() on read-only ExecuteQuery calls
• res.Err() checked after lazy for result.Next(ctx) loop
• Type assertions guarded (use GetRecordValue[T] or check ok)
• No side effects inside managed transaction callbacks
• session.Run() used for CALL IN TRANSACTIONS / auto-commit queries
• Sessions closed with defer session.Close(ctx)