package migra

  1. Overview
  2. Docs
A database migration tool and library for OCaml supporting PostgreSQL, MariaDB/MySQL, and SQLite

Install 

dune-project
 Dependency

github.com Readme Changelog Edit opam file Versions (6)

Authors

  1. D
    David Sinclair

Maintainers

  1. D
    David Sinclair <dsincl12@gmail.com>

Sources

migra-1.0.1.tbz
sha256=daaaab416e580e5b8dc9f0a74482e142cef6d77b248d995d320f6f882d3a9e35
sha512=8f60494b9ee6ac2e7e69a16eefce69d1e8c22e831fe28f600a42200e3086e2f4d15331323ad1848f7165e1c8ff30fe320445185b7e988325588293a66937966a

doc/src/migra.engine/types.ml.html

Source file types.ml

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type db_conn = (module Caqti_lwt.CONNECTION)

type file_error =
  | FileNotFound of string
  | InvalidFormat of string
  | ReadError of string * exn
  | AlreadyExists of string

type db_error =
  | ConnectionFailed of string * Caqti_error.t
  | QueryFailed of string * Caqti_error.t
  | TransactionFailed of string * Caqti_error.t
  | DatabaseNotFound of string
  | UrlParseError of string
  | ValidationError of string

type migration_error =
  | MissingSection of string * string (* file, section *)
  | EmptySection of string * string
  | ParseError of file_error
  | VersionConflict of int64 * string * string (* version, file_a, file_b *)
  | ChecksumMismatch of
      int64 * string (* version, file: applied file was modified *)
  | AppliedFileMissing of int64 (* version recorded as applied but no file *)
  | OutOfOrder of int64 * int64 (* pending version, latest applied version *)
  | ExecutionFailed of int64 * string (* version, error from running its SQL *)

type error =
  | FileError of file_error
  | DatabaseError of db_error
  | MigrationError of migration_error
  | DiscoveryError of string

let of_caqti_error ~context (err : Caqti_error.t) : error =
  DatabaseError (QueryFailed (context, err))

let rec show_error = function
  | FileError err -> show_file_error err
  | DatabaseError err -> show_db_error err
  | MigrationError err -> show_migration_error err
  | DiscoveryError msg -> Printf.sprintf "Discovery error: %s" msg

and show_file_error = function
  | FileNotFound path -> Printf.sprintf "File not found: %s" path
  | InvalidFormat msg -> Printf.sprintf "Invalid format: %s" msg
  | ReadError (path, exn) ->
      Printf.sprintf "Error reading file %s: %s" path (Printexc.to_string exn)
  | AlreadyExists path -> Printf.sprintf "File already exists: %s" path

and show_db_error = function
  | ConnectionFailed (context, err) ->
      Printf.sprintf "Database connection failed (%s): %s" context
        (Caqti_error.show err)
  | QueryFailed (context, err) ->
      Printf.sprintf "Query failed (%s): %s" context (Caqti_error.show err)
  | TransactionFailed (context, err) ->
      Printf.sprintf "Transaction failed (%s): %s" context
        (Caqti_error.show err)
  | DatabaseNotFound name -> Printf.sprintf "Database not found: %s" name
  | UrlParseError msg -> Printf.sprintf "URL parse error: %s" msg
  | ValidationError msg -> Printf.sprintf "Validation error: %s" msg

and show_migration_error = function
  | MissingSection (file, section) ->
      Printf.sprintf "Missing %s section in file: %s" section file
  | EmptySection (file, section) ->
      Printf.sprintf "Empty %s section in file: %s" section file
  | ParseError err -> show_file_error err
  | VersionConflict (version, file_a, file_b) ->
      Printf.sprintf
        "Migration version %Ld is duplicated by two files: %s and %s" version
        file_a file_b
  | ChecksumMismatch (version, file) ->
      Printf.sprintf
        "Migration %Ld (%s) was modified after it was applied (checksum \
         mismatch). Revert the file to its applied state, or roll the \
         migration back and re-apply it."
        version file
  | AppliedFileMissing version ->
      Printf.sprintf
        "Migration %Ld is recorded as applied but its file is missing from the \
         migrations directory."
        version
  | OutOfOrder (version, latest) ->
      Printf.sprintf
        "Migration %Ld is older than the most recently applied migration %Ld \
         (out-of-order migration); applying it now would change history."
        version latest
  | ExecutionFailed (version, msg) ->
      Printf.sprintf "Migration %Ld failed: %s" version msg