Specify a custom dial function per config #1527
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🔇 Additional comments (2)connector.go (2)
The timeout context
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Actionable comments generated: 2
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- connector.go (1 hunks)
- dsn.go (1 hunks)
Additional comments: 6
connector.go (3)
80-92: Please ensure to add tests that cover the new functionality introduced by the use of
c.cfg.DialFunc. This is crucial for verifying that the custom dial function works as expected and handles errors properly.80-92: Remember to update the documentation to include information about the new
DialFuncconfiguration option. This will help users understand how to use the new feature.80-92: If this is your first contribution to the project, please add yourself to the AUTHORS file as per the project's contribution guidelines.
dsn.go (3)
55-55: Verify whether the
DialFuncfield should be included in theFormatDSNmethod output. If it is intended to be part of the DSN string, appropriate handling needs to be added.55-55: Confirm that the
DialFuncfield does not need to be normalized within thenormalizemethod. If it does require normalization, appropriate logic should be added.55-55: Ensure that the
DialFuncfield does not need to be parsed from the DSN string in theparseDSNParamsfunction. If it should be included, parsing logic will need to be implemented.
connector.go
Outdated
| dctx, cancel = context.WithTimeout(ctx, c.cfg.Timeout) | ||
| defer cancel() | ||
| } | ||
| mc.netConn, err = c.cfg.DialFunc(dctx, mc.cfg.Addr) |
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There is a potential issue with error handling after the custom DialFunc is called. If an error occurs, it should be handled similarly to how it's handled after the global dial function or net.Dialer is called.
+ mc.netConn, err = c.cfg.DialFunc(dctx, mc.cfg.Addr)
+ if err != nil {
+ return nil, err
+ }Committable suggestion
❗ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation.
| mc.netConn, err = c.cfg.DialFunc(dctx, mc.cfg.Addr) | |
| mc.netConn, err = c.cfg.DialFunc(dctx, mc.cfg.Addr) | |
| if err != nil { | |
| return nil, err | |
| } |
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- connector.go (1 hunks)
- dsn.go (2 hunks)
Additional comments: 5
connector.go (1)
- 84-91: The implementation of the conditional dial function usage looks correct. It checks if a custom dial function is provided and uses it to establish a connection. If not, it falls back to the previously existing dialing mechanisms. This change aligns with the PR's objective to allow specifying a custom dial function for each configuration.
However, ensure that the custom
DialFuncis thoroughly tested, especially since the PR checklist indicates that tests for this new functionality are pending. It's important to cover various scenarios, including timeouts and error handling, to ensure the new dialing mechanism works as expected.dsn.go (4)
13-13: The import of the
contextpackage is appropriate given the newDialFuncfield in theConfigstruct.70-71: The addition of the
DialFuncfield to theConfigstruct enables per-configuration custom dial functions, which is a key objective of this PR.70-71: The function signature for
DialFuncis correct and follows the conventional pattern for dial functions in Go, taking acontext.Context, network type, and address, and returning anet.Connand an error.74-74: Verify if any normalization is required for the new
DialFuncfield within thenormalizemethod.
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Actionable comments generated: 1
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Files selected for processing (2)
- connector.go (1 hunks)
- dsn.go (1 hunks)
Additional comments: 3
connector.go (2)
- 90-97: The implementation of the custom
DialFuncusage within theConnectmethod is correctly checking ifDialFuncis provided and uses it if available. This approach allows for flexibility in establishing network connections, aligning with the PR's objectives. However, consider adding a comment explaining the purpose of the conditionalcontext.WithTimeoutcreation based onmc.cfg.Timeoutto clarify its intent for future maintainers.- 99-113: The fallback mechanism to use the default dialing method when
DialFuncis not provided is correctly implemented. However, there's a past comment bymethanesuggesting not to lookupdialswhenc.cfg.DialFunc != nil. This has been addressed by the conditional check forc.cfg.DialFuncat the beginning of this segment. It's good practice to ensure that unnecessary operations are avoided when a custom dial function is provided, enhancing performance and maintainability.dsn.go (1)
- 57-57: The addition of the
DialFuncfield to theConfigstruct is correctly implemented, allowing users to specify a custom dial function for connection establishment. This change effectively addresses the PR's objectives by enhancing flexibility in connection handling. It's important to ensure that documentation is updated to include information about this new field and how to use it, as it introduces a significant new capability for users.
connector.go
Outdated
| mc.parseTime = mc.cfg.ParseTime | ||
|
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||
| // Connect to Server | ||
| dialsLock.RLock() | ||
| dial, ok := dials[mc.cfg.Net] | ||
| dialsLock.RUnlock() | ||
| if ok { | ||
| if c.cfg.DialFunc != nil { | ||
| dctx := ctx | ||
| if mc.cfg.Timeout > 0 { | ||
| var cancel context.CancelFunc | ||
| dctx, cancel = context.WithTimeout(ctx, c.cfg.Timeout) | ||
| defer cancel() | ||
| } | ||
| mc.netConn, err = dial(dctx, mc.cfg.Addr) | ||
| mc.netConn, err = c.cfg.DialFunc(dctx, mc.cfg.Net, mc.cfg.Addr) | ||
| } else { | ||
| nd := net.Dialer{Timeout: mc.cfg.Timeout} | ||
| mc.netConn, err = nd.DialContext(ctx, mc.cfg.Net, mc.cfg.Addr) | ||
| dialsLock.RLock() | ||
| dial, ok := dials[mc.cfg.Net] | ||
| dialsLock.RUnlock() | ||
| if ok { | ||
| dctx := ctx | ||
| if mc.cfg.Timeout > 0 { | ||
| var cancel context.CancelFunc | ||
| dctx, cancel = context.WithTimeout(ctx, c.cfg.Timeout) | ||
| defer cancel() | ||
| } | ||
| mc.netConn, err = dial(dctx, mc.cfg.Addr) | ||
| } else { | ||
| nd := net.Dialer{Timeout: mc.cfg.Timeout} | ||
| mc.netConn, err = nd.DialContext(ctx, mc.cfg.Net, mc.cfg.Addr) | ||
| } | ||
| } | ||
|
|
||
| if err != nil { |
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📝 NOTE
This review was outside the diff hunks, and no overlapping diff hunk was found. Original lines [175-179]
The TLS configuration used in the default and custom dial functions does not specify a minimum version. It's recommended to explicitly set the minimum TLS version to TLS 1.3 to ensure stronger security guarantees. Additionally, the use of InsecureSkipVerify: true in the skip-verify case should be carefully considered, as it disables TLS/SSL certificate verification, making the connection vulnerable to man-in-the-middle (MTM) attacks. This should only be used for debugging purposes and not in production environments.
- cfg.TLS = &tls.Config{InsecureSkipVerify: true}
+ cfg.TLS = &tls.Config{InsecureSkipVerify: true, MinVersion: tls.VersionTLS13}And for other relevant TLS configurations, ensure MinVersion: tls.VersionTLS13 is added.
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I would like to see in the description of this PR an example of how that new feature would be used. Because I would to ensure this can't be implemented in another way. |
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I’m not quite sure what kind of example you want. I think my PR description has already explained it clearly. Without using different custom net names, RegisterDialContext can only register the SSH Tunnel globally. However, what I want is to be able to use multiple SSH Tunnels in one program without registering the net globally. In this PR, different Tunnels can be configured through DSN configuration. |
|
@methane Sorry to bother. Can we get this merged, or is there anything else I can do? |
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Actionable comments posted: 1
🧹 Outside diff range and nitpick comments (2)
dsn.go (2)
Line range hint
164-217: Consider updating the normalize methodThe
normalizemethod is responsible for setting default values and validating the configuration. Consider adding validation or default behavior for the newDialFuncfield in this method. This could include checking if a customDialFuncis provided and setting a default if it's not.Here's a suggested addition to the
normalizemethod:func (cfg *Config) normalize() error { // ... existing code ... // Set default DialFunc if not provided if cfg.DialFunc == nil { cfg.DialFunc = (&net.Dialer{Timeout: cfg.Timeout}).DialContext } // ... rest of the method ... }This ensures that there's always a valid dial function, defaulting to the standard net.Dialer if a custom one isn't provided.
58-58: Add documentation for DialFuncConsider adding documentation to explain how to use the new
DialFuncfield. This could include an example of how to set a custom dial function and any considerations users should keep in mind when using this feature.You could add a comment like this above the
DialFuncfield:// DialFunc allows for a custom dial function to be used for creating // connections. If not set, the default dialer will be used. // Example usage: // // cfg := mysql.NewConfig() // cfg.DialFunc = func(ctx context.Context, addr string) (net.Conn, error) { // return net.Dial("tcp", addr) // } DialFunc func(ctx context.Context, network, addr string) (net.Conn, error)
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📒 Files selected for processing (2)
- connector.go (1 hunks)
- dsn.go (1 hunks)
🧰 Additional context used
🔇 Additional comments (2)
dsn.go (2)
58-58: LGTM: Addition of DialFunc fieldThe new
DialFuncfield in theConfigstruct is a good addition. It allows users to specify a custom dialing function for creating network connections, which aligns with the PR objectives. The type signature is appropriate and matches the standardnet.Dialerfunction.
58-58: Reminder: Update Clone methodPlease ensure that the
Clonemethod of theConfigstruct has been updated to include the newDialFuncfield. This is necessary to ensure that any custom dial function is correctly copied when aConfiginstance is cloned.To verify if the
Clonemethod has been updated, you can run the following command:If the
Clonemethod doesn't include theDialFuncfield, consider updating it as follows:func (cfg *Config) Clone() *Config { cp := *cfg if cp.DialFunc != nil { cp.DialFunc = cfg.DialFunc } // ... existing code ... return &cp }
connector.go
Outdated
| if c.cfg.DialFunc != nil { | ||
| dctx := ctx | ||
| if mc.cfg.Timeout > 0 { | ||
| var cancel context.CancelFunc | ||
| dctx, cancel = context.WithTimeout(ctx, c.cfg.Timeout) | ||
| defer cancel() | ||
| } | ||
| mc.netConn, err = dial(dctx, mc.cfg.Addr) | ||
| mc.netConn, err = c.cfg.DialFunc(dctx, mc.cfg.Net, mc.cfg.Addr) | ||
| } else { | ||
| nd := net.Dialer{Timeout: mc.cfg.Timeout} | ||
| mc.netConn, err = nd.DialContext(ctx, mc.cfg.Net, mc.cfg.Addr) | ||
| dialsLock.RLock() | ||
| dial, ok := dials[mc.cfg.Net] | ||
| dialsLock.RUnlock() | ||
| if ok { | ||
| dctx := ctx | ||
| if mc.cfg.Timeout > 0 { | ||
| var cancel context.CancelFunc | ||
| dctx, cancel = context.WithTimeout(ctx, c.cfg.Timeout) | ||
| defer cancel() | ||
| } | ||
| mc.netConn, err = dial(dctx, mc.cfg.Addr) | ||
| } else { | ||
| nd := net.Dialer{Timeout: mc.cfg.Timeout} | ||
| mc.netConn, err = nd.DialContext(ctx, mc.cfg.Net, mc.cfg.Addr) | ||
| } |
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🛠️ Refactor suggestion
Refactor to eliminate duplicated timeout context creation code
The creation of the timeout context dctx is duplicated in both the if c.cfg.DialFunc != nil block and the if ok block within the else. To enhance maintainability and reduce code duplication, consider initializing dctx before these conditionals so it can be used in all branches.
Here's a suggested refactoring:
+ dctx := ctx
+ if mc.cfg.Timeout > 0 {
+ var cancel context.CancelFunc
+ dctx, cancel = context.WithTimeout(ctx, c.cfg.Timeout)
+ defer cancel()
+ }
if c.cfg.DialFunc != nil {
- dctx := ctx
- if mc.cfg.Timeout > 0 {
- var cancel context.CancelFunc
- dctx, cancel = context.WithTimeout(ctx, c.cfg.Timeout)
- defer cancel()
- }
mc.netConn, err = c.cfg.DialFunc(dctx, mc.cfg.Net, mc.cfg.Addr)
} else {
dialsLock.RLock()
dial, ok := dials[mc.cfg.Net]
dialsLock.RUnlock()
if ok {
- dctx := ctx
- if mc.cfg.Timeout > 0 {
- var cancel context.CancelFunc
- dctx, cancel = context.WithTimeout(ctx, c.cfg.Timeout)
- defer cancel()
- }
mc.netConn, err = dial(dctx, mc.cfg.Addr)
} else {
nd := net.Dialer{Timeout: mc.cfg.Timeout}
- mc.netConn, err = nd.DialContext(ctx, mc.cfg.Net, mc.cfg.Addr)
+ mc.netConn, err = nd.DialContext(dctx, mc.cfg.Net, mc.cfg.Addr)
}
}📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| if c.cfg.DialFunc != nil { | |
| dctx := ctx | |
| if mc.cfg.Timeout > 0 { | |
| var cancel context.CancelFunc | |
| dctx, cancel = context.WithTimeout(ctx, c.cfg.Timeout) | |
| defer cancel() | |
| } | |
| mc.netConn, err = dial(dctx, mc.cfg.Addr) | |
| mc.netConn, err = c.cfg.DialFunc(dctx, mc.cfg.Net, mc.cfg.Addr) | |
| } else { | |
| nd := net.Dialer{Timeout: mc.cfg.Timeout} | |
| mc.netConn, err = nd.DialContext(ctx, mc.cfg.Net, mc.cfg.Addr) | |
| dialsLock.RLock() | |
| dial, ok := dials[mc.cfg.Net] | |
| dialsLock.RUnlock() | |
| if ok { | |
| dctx := ctx | |
| if mc.cfg.Timeout > 0 { | |
| var cancel context.CancelFunc | |
| dctx, cancel = context.WithTimeout(ctx, c.cfg.Timeout) | |
| defer cancel() | |
| } | |
| mc.netConn, err = dial(dctx, mc.cfg.Addr) | |
| } else { | |
| nd := net.Dialer{Timeout: mc.cfg.Timeout} | |
| mc.netConn, err = nd.DialContext(ctx, mc.cfg.Net, mc.cfg.Addr) | |
| } | |
| dctx := ctx | |
| if mc.cfg.Timeout > 0 { | |
| var cancel context.CancelFunc | |
| dctx, cancel = context.WithTimeout(ctx, c.cfg.Timeout) | |
| defer cancel() | |
| } | |
| if c.cfg.DialFunc != nil { | |
| mc.netConn, err = c.cfg.DialFunc(dctx, mc.cfg.Net, mc.cfg.Addr) | |
| } else { | |
| dialsLock.RLock() | |
| dial, ok := dials[mc.cfg.Net] | |
| dialsLock.RUnlock() | |
| if ok { | |
| mc.netConn, err = dial(dctx, mc.cfg.Addr) | |
| } else { | |
| nd := net.Dialer{Timeout: mc.cfg.Timeout} | |
| mc.netConn, err = nd.DialContext(dctx, mc.cfg.Net, mc.cfg.Addr) | |
| } | |
| } |
dsn.go
Outdated
| ReadTimeout time.Duration // I/O read timeout | ||
| WriteTimeout time.Duration // I/O write timeout | ||
| Logger Logger // Logger | ||
| DialFunc func(ctx context.Context, network, addr string) (net.Conn, error) // Specifies the dial function for creating connections |
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| DialFunc func(ctx context.Context, network, addr string) (net.Conn, error) // Specifies the dial function for creating connections | |
| // Specifies the dial function for creating connections | |
| DialFunc func(ctx context.Context, network, addr string) (net.Conn, error) |
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Actionable comments posted: 0
🧹 Outside diff range and nitpick comments (1)
dsn.go (1)
58-59: Consider enhancing the documentation while maintaining conciseness.The documentation could benefit from a brief mention of the default behavior when
DialFuncis nil.- // DialFunc specifies the dial function for creating connections + // DialFunc specifies an optional dial function for creating connections. + // If nil, the default network dialer is used.
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dsn.go(1 hunks)
🔇 Additional comments (3)
dsn.go (3)
Line range hint 201-219: LGTM! The Clone method correctly handles DialFunc.
The shallow copy cp := *cfg adequately handles the function pointer DialFunc. No explicit copying is needed.
Line range hint 221-565: LGTM! Correct handling of DialFunc in DSN operations.
The DialFunc field is appropriately excluded from DSN serialization and parsing operations, as it's a runtime configuration that should be set programmatically, similar to TLS and Loc fields.
58-59: Tests needed for the new DialFunc feature.
Please add tests to verify:
- Custom dialers work as expected
- Nil DialFunc falls back to default behavior
- Context cancellation is properly handled
Specify a custom dial function per config instead of using RegisterDialContext.
Description
Specify a custom dial function per config instead of using RegisterDialContext. It's hard to bind different state infomation for dialing with
RegisterDialContext. Like SSH tunneling, if we want to use diffrent SSH connections, uniquenetfor RegisterDialContext is required If I'm not wrong.Use cases:
Config/dsnChecklist
Summary by CodeRabbit
DialFuncfield in theConfigstruct for enhanced control over connection establishment.Configstruct documentation to reflect the addition of theDialFuncfield, enabling more controlled connection processes.