53 lines
1.4 KiB
Go
53 lines
1.4 KiB
Go
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// Migration tooling
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//
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// Runs migrations in-order based on files found in the migration
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// root directory provided as argument.
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package main
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import (
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"bufio"
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"bytes"
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"os"
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)
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var commentPrefix = []byte("--")
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var requirementPrefix = []byte("requires:")
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// Removes the provided prefix from the byte slice and removes
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// any spaces leading or trailing the resulting slice.
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//
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// If the prefix is not present, nothing is removed except
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// the leading and trailing spaces.
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func cutPrefixAndTrim(b []byte, prefix []byte) []byte {
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withoutPrefix, _ := bytes.CutPrefix(b, prefix)
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return bytes.TrimSpace(withoutPrefix)
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}
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// Extracts any migration headers present in the migration source file.
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// Headers are left in comments of the form:
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// -- <header-name>: ...
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// Anything else than the known headers is ignored.
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func gatherMigrationHeaders(migrationFile *os.File) MigrationHeaders {
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scanner := bufio.NewScanner(migrationFile)
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requirements := []string{}
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for scanner.Scan() {
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currentBytes := scanner.Bytes()
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if !bytes.HasPrefix(currentBytes, commentPrefix) {
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continue
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}
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commentBytes := cutPrefixAndTrim(currentBytes, commentPrefix)
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if bytes.HasPrefix(commentBytes, requirementPrefix) {
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reqName := cutPrefixAndTrim(commentBytes, requirementPrefix)
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requirements = append(requirements, string(reqName))
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}
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}
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return MigrationHeaders{Requirements: requirements}
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}
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