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| -rw-r--r-- | users/wpcarro/website/blog/posts.nix | 7 | ||||
| -rw-r--r-- | users/wpcarro/website/blog/posts/git-filter-repo-note.md | 59 |
2 files changed, 66 insertions, 0 deletions
diff --git a/users/wpcarro/website/blog/posts.nix b/users/wpcarro/website/blog/posts.nix index fcb2f5659e3b..ba0c6abb62f1 100644 --- a/users/wpcarro/website/blog/posts.nix +++ b/users/wpcarro/website/blog/posts.nix @@ -64,4 +64,11 @@ content = ./posts/nix-shell-note.md; draft = false; } + { + key = "git-filter-repo-note"; + title = "git-filter-repo (note to self)"; + date = 1665163559; + content = ./posts/git-filter-repo-note.md; + draft = false; + } ] diff --git a/users/wpcarro/website/blog/posts/git-filter-repo-note.md b/users/wpcarro/website/blog/posts/git-filter-repo-note.md new file mode 100644 index 000000000000..ac4ac79ec517 --- /dev/null +++ b/users/wpcarro/website/blog/posts/git-filter-repo-note.md @@ -0,0 +1,59 @@ +## Background + +- I recently used `git-filter-repo` to scrub cleartext secrets from a + repository. +- We pin some services' deployments to commit SHAs. +- These commit SHAs are no longer reachable from `origin/main`. + +## Problem + +If the `git` garbage-collects any of the commits to which services are pinned, +and that service attempts to deploy/redeploy, it will fail. + +`git for-each-ref --contains $SHA` will report all of the refs that can reach +some commit, `$SHA`. This may be things like: +- `refs/replace`: `git-filter-repo` artifacts +- `refs/stash` +- some local branches +- some remote branches + +One solution might involve avoid garbage-collection. But if any of our pinned +commits contained sensitive cleartext we will *want* to ensure that `git` purges +these. + +Instead let's find the SHAs of the new, rewritten commits and replace the pinned +versions with those. + +## Solution + +Essentially we want to find a commit with the same *tree* state as the currently +pinned commit. Here are two ways to get that info... + +This way is indirect, but provides more context: + +```shell +λ git cat-file -p $SHA +tree d011a1dd4a3c5c4c6455ab3592fa2bf71d551d22 # <-- copy this tree info +parent ba88bbf8de61be932184631244d2ec0ec8205cb8 +author William Carroll <wpcarro@gmail.com> 1664993052 -0700 +committer William Carroll <wpcarro@gmail.com> 1665116042 -0700 + +feat(florp): Florp can now flarp + +You're welcome :) +``` + +This way is more direct: + +```shell +λ git log -1 --format=%T $SHA +``` + +Now that we have the SHA of the desired *tree* state, let's query `git` for +commits that share this state. + +```shell +λ git log --format='%H %T' | grep $(git log --format=%T -1 $SHA) | awk '{ print $1 }' +``` + +Hopefully this helps! |