Table Extractor Hook and _lakefs_tables format

pkg/actions/lua.go

@@ -205,7 +205,7 @@ func NewLuaHook(h ActionHook, action *Action, cfg Config, e *http.Server) (Hook,
 			Args:   args,
 		}, nil
 	} else if !errors.Is(err, errMissingKey) {
-		// 'script' was provided but is empty or of the wrong type..
+		// 'script' was provided but is empty or of the wrong type.
 		return nil, err
 	}
 

pkg/actions/lua/lakefs/catalogexport/hive.lua

@@ -0,0 +1,78 @@
+local pathlib = require("path")
+local utils = require("lakefs/catalogexport/internal")
+local strings = require("strings")
+local DEFAULT_PAGE_SIZE = 30 
+
+-- extract partition prefix from full path
+function extract_partitions_path(partitions, path)
+    if partitions == nil or #partitions == 0 then
+        return ""
+    end
+    local idx = 1
+    local is_partition_prefix = strings.has_prefix(path, partitions[1])
+    for part_idx, partition in ipairs(partitions) do
+        local col_substr = "/" ..  partition .. "="
+        -- if partition is the path prefix and we are the that first partition remove /
+        if part_idx == 1 and is_partition_prefix then
+            col_substr = partition .. "="
+        end
+        local i, j = string.find(path, col_substr, idx)
+        if i == nil then
+            return nil
+        end
+        local separator_idx = string.find(path, "/", j+1)
+        -- verify / found and there is something in between = ... / 
+        if separator_idx == nil or separator_idx <= (j + 1) then
+            return nil
+        end
+        idx = separator_idx
+    end
+    return string.sub(path, 1, idx)
+end
+
+-- Hive format partition iterator each result set is a collection of files under the same partition
+function extract_partition_pager(client, repo_id, commit_id, base_path, partition_cols, page_size)
+    local target_partition = ""
+    local pager = utils.lakefs_object_pager(client, repo_id, commit_id, "", base_path,"", page_size or DEFAULT_PAGE_SIZE)
+    local page = pager()
+    return function()
+        if page == nil then
+            return nil
+        end
+        local partition_entries = {}
+        while true do
+            if #page == 0 then
+                page = pager()
+                if page == nil then -- no more records
+                    return target_partition, partition_entries
+                end
+            end
+            local entry = page[1]
+            if not pathlib.is_hidden(entry.path) then
+                local partition_key = extract_partitions_path(partition_cols, entry.path)
+                -- first time: if not set, assign current object partition as the target_partition key
+                if target_partition == "" then
+                    target_partition = partition_key
+                end
+                -- break if current entry does not belong to the target_partition
+                if partition_key ~= target_partition then
+                    local partition_result = target_partition
+                    target_partition = partition_key
+                    return partition_result, partition_entries
+                end
+                table.insert(partition_entries, {
+                    physical_address = entry.physical_address,
+                    path = entry.path,
+                    size = entry.size_bytes,
+                    checksum = entry.checksum
+                })
+                -- remove entry only if its part of the current partition
+                table.remove(page, 1)
+            end
+        end
+    end
+end
+
+return {
+    extract_partition_pager=extract_partition_pager,
+}

pkg/actions/lua/lakefs/catalogexport/internal.lua

@@ -0,0 +1,49 @@
+local DEFAULT_SHORT_DIGEST_LEN=6
+
+function short_digest(digest, len)
+    return digest:sub(1, len or DEFAULT_SHORT_DIGEST_LEN)
+end 
+
+-- paginate lakefs api 
+function lakefs_paginiated_api(api_call, after)
+    local next_offset = after
+    local has_more = true
+    return function()
+        if not has_more then
+            return nil
+        end
+        local code, resp = api_call(next_offset)
+        if code < 200 or code >= 300 then
+            error("lakeFS: api return non-2xx" .. tostring(code))
+        end
+        has_more = resp.pagination.has_more
+        next_offset = resp.pagination.next_offset
+        return resp.results
+    end
+end
+
+-- paginage over lakefs objects 
+function lakefs_object_pager(lakefs_client, repo_id, commit_id, after, prefix, delimiter, page_size)
+    return lakefs_paginiated_api(function(next_offset)
+        return lakefs_client.list_objects(repo_id, commit_id, next_offset, prefix, delimiter, page_size or 30)
+    end, after)
+end
+
+-- resolve ref value from action global, used as part of setting default table name
+function ref_from_branch_or_tag(action_info)
+    local event = action_info.event_type
+    if event == "pre-create-tag" or event == "post-create-tag" then
+        return action_info.tag_id
+    elseif event == "pre-create-branch" or event == "post-create-branch" or "post-commit" or "post-merge" then
+        return action_info.branch_id
+    else
+        error("unsupported event type: " .. action_info.event_type)
+    end
+end
+
+return {
+    short_digest=short_digest,
+    ref_from_branch_or_tag=ref_from_branch_or_tag,
+    lakefs_object_pager=lakefs_object_pager, 
+    lakefs_paginiated_api=lakefs_paginiated_api,
+}

pkg/actions/lua/lakefs/catalogexport/table_extractor.lua

@@ -0,0 +1,53 @@
+local pathlib = require("path")
+local strings = require("strings")
+local yaml = require("encoding/yaml")
+local utils = require("lakefs/catalogexport/internal")
+
+local LAKEFS_TABLES_BASE = "_lakefs_tables/"
+
+-- check if lakefs entry is a table spec under _lakefs_tables/
+function is_table_obj(entry, tables_base)
+    if entry.path_type ~= "object" then
+        return false
+    end
+    local path = entry.path
+    if strings.has_prefix(path, tables_base) then
+        -- remove _lakefs_tables/ from path
+        path = entry.path:sub(#tables_base, #path)
+    end
+    return not pathlib.is_hidden(path) and strings.has_suffix(path, ".yaml")
+end
+
+-- list all YAML files under _lakefs_tables/*
+function list_table_descriptor_entries(client, repo_id, commit_id)
+    local table_entries = {}
+    local page_size = 30
+    local pager = utils.lakefs_object_pager(client, repo_id, commit_id, "", LAKEFS_TABLES_BASE,"", page_size)
+    for entries in pager do
+        for _, entry in ipairs(entries) do
+            if is_table_obj(entry, LAKEFS_TABLES_BASE) then
+                table.insert(table_entries, {
+                    physical_address = entry.physical_address,
+                    path = entry.path
+                })
+            end
+        end
+    end
+    return table_entries
+end
+
+-- table as parsed YAML object
+function get_table_descriptor(client, repo_id, commit_id, logical_path)
+    local code, content = client.get_object(repo_id, commit_id, logical_path)
+    if code ~= 200 then
+        error("could not fetch data file: HTTP " .. tostring(code))
+    end
+    local descriptor = yaml.unmarshal(content)
+    descriptor.partition_columns = descriptor.partition_columns or {}
+    return descriptor
+end
+
+return {
+    list_table_descriptor_entries = list_table_descriptor_entries,
+    get_table_descriptor = get_table_descriptor,
+}

pkg/actions/lua/load.go

@@ -1,19 +1,29 @@
 package lua
 
 import (
+	"bytes"
+	"embed"
+	"errors"
 	"fmt"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"strings"
 
 	"github.com/Shopify/go-lua"
+	"github.com/hashicorp/go-multierror"
 )
 
 const (
 	pathListSeparator = ';'
-	defaultPath       = "./?.lua"
+	defaultPath       = "?.lua"
 )
 
+//go:embed lakefs/catalogexport/*.lua
+var luaEmbeddedCode embed.FS
+
+var ErrNoFile = errors.New("no file")
+
 func findLoader(l *lua.State, name string) {
 	var msg string
 	if l.Field(lua.UpValueIndex(1), "searchers"); !l.IsTable(3) {
@@ -35,6 +45,61 @@ func findLoader(l *lua.State, name string) {
 	}
 }
 
+func findFile(l *lua.State, name, field, dirSep string) (string, error) {
+	l.Field(lua.UpValueIndex(1), field)
+	path, ok := l.ToString(-1)
+	if !ok {
+		lua.Errorf(l, "'package.%s' must be a string", field)
+	}
+	return searchPath(name, path, ".", dirSep)
+}
+
+func checkLoad(l *lua.State, loaded bool, fileName string) int {
+	if loaded { // Module loaded successfully?
+		l.PushString(fileName) // Second argument to module.
+		return 2               // Return open function & file name.
+	}
+	m := lua.CheckString(l, 1)
+	e := lua.CheckString(l, -1)
+	lua.Errorf(l, "error loading module '%s' from file '%s':\n\t%s", m, fileName, e)
+	panic("unreachable")
+}
+
+func searcherLua(l *lua.State) int {
+	name := lua.CheckString(l, 1)
+	filename, err := findFile(l, name, "path", string(filepath.Separator))
+	if err != nil {
+		return 1 // Module isn't found in this path.
+	}
+
+	return checkLoad(l, loadFile(l, filename, "") == nil, filename)
+}
+
+func loadFile(l *lua.State, fileName, mode string) error {
+	fileNameIndex := l.Top() + 1
+	fileError := func(what string) error {
+		fileName, _ := l.ToString(fileNameIndex)
+		l.PushFString("cannot %s %s", what, fileName[1:])
+		l.Remove(fileNameIndex)
+		return lua.FileError
+	}
+	l.PushString("@" + fileName)
+	data, err := luaEmbeddedCode.ReadFile(fileName)
+	if err != nil {
+		return fileError("open")
+	}
+	s, _ := l.ToString(-1)
+	err = l.Load(bytes.NewReader(data), s, mode)
+	switch {
+	case err == nil, errors.Is(err, lua.SyntaxError), errors.Is(err, lua.MemoryError): // do nothing
+	default:
+		l.SetTop(fileNameIndex)
+		return fileError("read")
+	}
+	l.Remove(fileNameIndex)
+	return err
+}
+
 func searcherPreload(l *lua.State) int {
 	name := lua.CheckString(l, 1)
 	l.Field(lua.RegistryIndex, "_PRELOAD")
@@ -46,7 +111,7 @@ func searcherPreload(l *lua.State) int {
 }
 
 func createSearchersTable(l *lua.State) {
-	searchers := []lua.Function{searcherPreload}
+	searchers := []lua.Function{searcherPreload, searcherLua}
 	l.CreateTable(len(searchers), 0)
 	for i, s := range searchers {
 		l.PushValue(-2)
@@ -55,6 +120,33 @@ func createSearchersTable(l *lua.State) {
 	}
 }
 
+func searchPath(name, path, sep, dirSep string) (string, error) {
+	var err error
+	if sep != "" {
+		name = strings.ReplaceAll(name, sep, dirSep) // Replace sep by dirSep.
+	}
+	path = strings.ReplaceAll(path, string(pathListSeparator), string(filepath.ListSeparator))
+	for _, template := range filepath.SplitList(path) {
+		if template == "" {
+			continue
+		}
+		filename := strings.ReplaceAll(template, "?", name)
+		if readable(filename) {
+			return filename, nil
+		}
+		err = multierror.Append(err, fmt.Errorf("%w %s", ErrNoFile, filename))
+	}
+	return "", err
+}
+
+func readable(name string) bool {
+	if !fs.ValidPath(name) {
+		return false
+	}
+	info, err := fs.Stat(luaEmbeddedCode, name)
+	return err == nil && !info.IsDir()
+}
+
 func noEnv(l *lua.State) bool {
 	l.Field(lua.RegistryIndex, "LUA_NOENV")
 	b := l.ToBoolean(-1)
@@ -84,15 +176,18 @@ var packageLibrary = []lua.RegistryFunction{
 		return 3 // Return nil, error message, and where.
 	}},
 	{Name: "searchpath", Function: func(l *lua.State) int {
-		_ = lua.CheckString(l, 1)
-		_ = lua.CheckString(l, 2)
-		_ = lua.OptString(l, 3, ".")
-		_ = lua.OptString(l, 4, string(filepath.Separator))
-
-		l.PushNil()
-		l.PushString("searchpath not enabled; check your Lua installation")
-		l.PushString("absent")
-		return 3 // Return nil, error message, and where.
+		name := lua.CheckString(l, 1)
+		path := lua.CheckString(l, 2)
+		sep := lua.OptString(l, 3, ".")
+		dirSep := lua.OptString(l, 4, string(filepath.Separator))
+		f, err := searchPath(name, path, sep, dirSep)
+		if err != nil {
+			l.PushNil()
+			l.PushString(err.Error())
+			return 2
+		}
+		l.PushString(f)
+		return 1
 	}},
 }