commit 70fe73413fdf0b2224ec54f921e1e54af797da81 · anil.recoil.org/ocaml-conpool

+51 -53

lib/conpool.ml

···

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         | Invalid_config of string

     

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         | Invalid_endpoint of string

     

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       -
       exception Pool_error of error

     

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       -
       

     

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       let pp_error ppf = function

     

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         | Dns_resolution_failed { hostname } ->

     

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             Fmt.pf ppf "DNS resolution failed for hostname: %s" hostname

     
···

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       let resolve_endpoint (pool : ('clock, 'net) internal) endpoint =

     

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         Log.debug (fun m -> m "Resolving %a..." Endpoint.pp endpoint);

     

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         let addrs =

     

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           Eio.Net.getaddrinfo_stream pool.net (Endpoint.host endpoint)

     

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             ~service:(string_of_int (Endpoint.port endpoint))

     

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         in

     

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         Log.debug (fun m -> m "Got address list for %a" Endpoint.pp endpoint);

     

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         match addrs with

     

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         | addr :: _ ->

     

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             Log.debug (fun m ->

     

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                 m "Resolved %a to %a" Endpoint.pp endpoint Eio.Net.Sockaddr.pp addr);

     

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             addr

     

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         | [] ->

     

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             Log.err (fun m ->

     

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                 m "Failed to resolve hostname: %s" (Endpoint.host endpoint));

     

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             raise

     

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               (Pool_error

     

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                  (Dns_resolution_failed { hostname = Endpoint.host endpoint }))

     

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         try

     

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           let addrs =

     

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             Eio.Net.getaddrinfo_stream pool.net (Endpoint.host endpoint)

     

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               ~service:(string_of_int (Endpoint.port endpoint))

     

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           in

     

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           Log.debug (fun m -> m "Got address list for %a" Endpoint.pp endpoint);

     

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           match addrs with

     

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           | addr :: _ ->

     

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               Log.debug (fun m ->

     

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                   m "Resolved %a to %a" Endpoint.pp endpoint Eio.Net.Sockaddr.pp addr);

     

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               addr

     

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           | [] ->

     

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               Log.err (fun m ->

     

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                   m "Failed to resolve hostname: %s" (Endpoint.host endpoint));

     

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               raise (err (Dns_resolution_failed { hostname = Endpoint.host endpoint }))

     

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         with Eio.Io _ as ex ->

     

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           let bt = Printexc.get_raw_backtrace () in

     

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           Eio.Exn.reraise_with_context ex bt "resolving %a" Endpoint.pp endpoint

     

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       (** {1 Connection Creation with Retry} *)

     

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···

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           Log.err (fun m ->

     

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               m "Failed to connect to %a after %d attempts" Endpoint.pp endpoint

     

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                 retry_count);

     

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           raise

     

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             (Pool_error

     

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                (Connection_failed { endpoint; attempts = retry_count; last_error }))

     

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           raise (err (Connection_failed { endpoint; attempts = retry_count; last_error }))

     

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         end;

     

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         Log.debug (fun m ->

     
···

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           (* Connect with optional timeout *)

     

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           let socket =

     

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             match Config.connect_timeout pool.config with

     

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             | Some timeout ->

     

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                 Eio.Time.with_timeout_exn pool.clock timeout (fun () ->

     

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                     Eio.Net.connect ~sw:pool.sw pool.net addr)

     

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             | None -> Eio.Net.connect ~sw:pool.sw pool.net addr

     

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             try

     

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               match Config.connect_timeout pool.config with

     

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               | Some timeout ->

     

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                   Eio.Time.with_timeout_exn pool.clock timeout (fun () ->

     

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                       Eio.Net.connect ~sw:pool.sw pool.net addr)

     

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               | None -> Eio.Net.connect ~sw:pool.sw pool.net addr

     

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             with Eio.Io _ as ex ->

     

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               let bt = Printexc.get_raw_backtrace () in

     

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               Eio.Exn.reraise_with_context ex bt "connecting to %a" Endpoint.pp endpoint

     

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           in

     

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           Log.debug (fun m ->

     
···

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             | None ->

     

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                 (socket :> connection)

     

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             | Some tls_config ->

     

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                 Log.debug (fun m ->

     

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                     m "Initiating TLS handshake with %a" Endpoint.pp endpoint);

     

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                 let host =

     

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                   Domain_name.(host_exn (of_string_exn (Endpoint.host endpoint)))

     

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                 in

     

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                 let tls_flow = Tls_eio.client_of_flow ~host tls_config socket in

     

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                 Log.info (fun m ->

     

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                     m "TLS connection established to %a" Endpoint.pp endpoint);

     

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                 (tls_flow :> connection)

     

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                 try

     

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                   Log.debug (fun m ->

     

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                       m "Initiating TLS handshake with %a" Endpoint.pp endpoint);

     

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                   let host =

     

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                     Domain_name.(host_exn (of_string_exn (Endpoint.host endpoint)))

     

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                   in

     

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                   let tls_flow = Tls_eio.client_of_flow ~host tls_config socket in

     

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                   Log.info (fun m ->

     

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                       m "TLS connection established to %a" Endpoint.pp endpoint);

     

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                   (tls_flow :> connection)

     

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                 with Eio.Io _ as ex ->

     

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                   let bt = Printexc.get_raw_backtrace () in

     

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                   Eio.Exn.reraise_with_context ex bt "TLS handshake with %a" Endpoint.pp endpoint

     

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           in

     

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           let now = get_time pool in

     
···

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             mutex = Eio.Mutex.create ();

     

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           }

     

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         with

     

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         | Eio.Time.Timeout as e ->

     

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         | Eio.Time.Timeout ->

     

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             Log.warn (fun m ->

     

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                 m "Connection timeout to %a (attempt %d)" Endpoint.pp endpoint attempt);

     

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             let error_msg = Printexc.to_string e in

     

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             if attempt >= Config.connect_retry_count pool.config then

     

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               (* Last attempt - convert to our error type *)

     

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               match Config.connect_timeout pool.config with

     

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               | Some timeout ->

     

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                   raise (Pool_error (Connection_timeout { endpoint; timeout }))

     

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                   raise (err (Connection_timeout { endpoint; timeout }))

     

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               | None ->

     

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                   raise

     

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                     (Pool_error

     

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                        (Connection_failed

     

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                           { endpoint; attempts = attempt; last_error = error_msg }))

     

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                   raise (err (Connection_failed

     

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                           { endpoint; attempts = attempt; last_error = "Timeout" }))

     

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             else begin

     

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               (* Retry with exponential backoff *)

     

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               let delay =

     
···

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                 *. (2.0 ** float_of_int (attempt - 1))

     

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               in

     

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               Eio.Time.sleep pool.clock delay;

     

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               create_connection_with_retry pool endpoint (attempt + 1) error_msg

     

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               create_connection_with_retry pool endpoint (attempt + 1) "Timeout"

     

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             end

     

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         | e ->

     

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             (* Other errors - retry with backoff *)

     

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             let error_msg = Printexc.to_string e in

     

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         | Eio.Io _ as ex ->

     

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             (* Eio IO errors - retry with backoff and add context on final failure *)

     

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             let error_msg = Printexc.to_string ex in

     

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             Log.warn (fun m ->

     

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                 m "Connection attempt %d to %a failed: %s" attempt Endpoint.pp

     

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                   endpoint error_msg);

     
···

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               Eio.Time.sleep pool.clock delay;

     

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               create_connection_with_retry pool endpoint (attempt + 1) error_msg)

     

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             else

     

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               raise

     

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                 (Pool_error

     

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                    (Connection_failed

     

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                       { endpoint; attempts = attempt; last_error = error_msg }))

     

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               let bt = Printexc.get_raw_backtrace () in

     

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               Eio.Exn.reraise_with_context ex bt "after %d retry attempts" attempt

     

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       let create_connection (pool : ('clock, 'net) internal) endpoint =

     

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         create_connection_with_retry pool endpoint 1 "No attempts made"

     
···

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       let with_connection t endpoint f =

     

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         Eio.Switch.run (fun sw -> f (connection ~sw t endpoint))

     

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       -
       

     

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       let with_connection_exn t endpoint f =

     

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         try with_connection t endpoint f with Pool_error e -> raise (err e)

     

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       (** {1 Public API - Statistics} *)

     

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+21 -16

lib/conpool.mli

···

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         | Invalid_config of string  (** Invalid configuration parameter *)

     

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         | Invalid_endpoint of string  (** Invalid endpoint specification *)

     

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       50
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       exception Pool_error of error

     

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       (** Exception raised by pool operations.

     

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       +
       type Eio.Exn.err += E of error

     

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       (** Extension of Eio's error type for connection pool errors.

     

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       +
       

     

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           Pool operations raise [Eio.Io] exceptions with context information added at

     

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       +
           each layer. The innermost error is often [E error], wrapped with context

     

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           strings that describe the operation being performed.

     

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           Most pool operations can raise this exception. Use {!pp_error} to get

     

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           human-readable error messages. *)

     

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           Example error message:

     

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       +
           {[

     

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             Eio.Io Conpool Dns_resolution_failed { hostname = "invalid.example" },

     

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               resolving invalid.example:443,

     

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       +
               connecting to invalid.example:443,

     

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               after 3 retry attempts

     

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       +
           ]}

     

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       -
       type Eio.Exn.err += E of error

     

       57
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       -
       (** Extension of Eio's error type for connection pool errors. *)

     

       65
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       +
           Use {!pp_error} to format just the error code, or let Eio format the full

     

       66
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       +
           exception with context. *)

     

       58
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       val err : error -> exn

     

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       (** [err e] is [Eio.Exn.create (E e)].

     

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           This converts a connection pool error to an Eio exception, allowing it to

     

       63
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       -
           be handled uniformly with other Eio I/O errors. *)

     

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       +
           be handled uniformly with other Eio I/O errors and enabling context to be

     

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       +
           added via [Eio.Exn.reraise_with_context]. *)

     

       64
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       val pp_error : error Fmt.t

     

       66
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       -
       (** Pretty-printer for error values. *)

     

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       +
       (** Pretty-printer for error values (without context).

     

       77
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       +
       

     

       78
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       +
           For full error messages including context, use [Eio.Exn.pp] or simply let

     

       79
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       +
           the exception be printed naturally. *)

     

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       (** {1 Connection Types} *)

     

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···

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                 let buf = Eio.Buf_read.of_flow conn ~max_size:4096 in

     

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                 Eio.Buf_read.take_all buf)

     

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           ]} *)

     

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       -
       

     

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       val with_connection_exn : t -> Endpoint.t -> (connection -> 'a) -> 'a

     

       147
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       -
       (** [with_connection_exn pool endpoint fn] is like {!with_connection} but

     

       148
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       -
           converts {!Pool_error} exceptions to [Eio.Io] exceptions for better

     

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           integration with Eio error handling.

     

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       -
       

     

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           This is useful when you want pool errors to be handled uniformly with other

     

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       -
           Eio I/O errors. *)

     

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       (** {1 Statistics & Monitoring} *)

     

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