Add a Go package for reading MaxMind GeoLite2 City and ASN databases.
- ParseConf: parses geoipupdate-style config files (AccountID,
LicenseKey, EditionIDs, DatabaseDirectory)
- Databases: holds open City + ASN readers; Open() loads both
editions from a directory, extracting .mmdb from tar.gz in memory
without writing to disk
- FindTarGz: resolves cache paths, preferring *_LATEST.tar.gz
- Lookup: returns city, region, country, ASN, and AS org for an IP
- DownloadBase constant, TarGzName helper, DefaultConfPaths and
DefaultCacheDir conveniences
Integration tests verify download and conditional-get freshness.
Periodically-updated shallow clone for repos used as a data source.
One Fetch verb (clone-or-pull-or-skip) drives both the Fetcher
interface and per-File handles. MaxAge gates on FETCH_HEAD mtime so
short-lived CLI invocations don't hammer the remote across process
restarts; an in-memory 1s debounce coalesces concurrent Fetches.
Hardens git invocations against argument injection: validates
branch/ref shape, rejects URLs starting with '-', and uses '--'
separators before positional args. Userinfo in URL is redacted from
error output (both args echo and git's own messages).
Apply the same lazy-error pattern fix to all backends, plus regression
tests that catch the bug.
pgmigrate is the confirmed-broken case (pgx/v5's Conn.Query is lazy and
surfaces 42P01 at rows.Err() once the prepared statement cache is primed).
The defensive check at rows.Err() is also added to mymigrate and msmigrate
in case their drivers exhibit similar behavior in some configurations.
litemigrate is refactored to probe sqlite_master with errors.Is(sql.ErrNoRows)
instead of string-matching the error message — SQLite returns the generic
SQLITE_ERROR code for "no such table" so a typed-error approach isn't
possible at the driver layer; the probe lets us use idiomatic errors.Is.
Tests:
- litemigrate: in-memory SQLite, runs on every go test (no infra)
- pgmigrate: PG_TEST_URL env-gated; verified against real Postgres,
TestAppliedAfterDropTable reproduces the agent's exact error
message ("reading rows: ... 42P01") without the fix
- mymigrate: MYSQL_TEST_DSN env-gated
- msmigrate: MSSQL_TEST_URL env-gated; verified against real SQL Server
Each backend has four cases: missing table, populated table, empty table,
and table-dropped-after-cache-primed (the lazy-error scenario).
