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author | EuAndreh <eu@euandre.org> | 2025-04-18 02:17:12 -0300 |
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committer | EuAndreh <eu@euandre.org> | 2025-04-18 02:48:42 -0300 |
commit | 020c1e77489b772f854bb3288b9c8d2818a6bf9d (patch) | |
tree | 142aec725a52162a446ea7d947cb4347c9d573c9 /src/content/blog/2018/08 | |
parent | Makefile: Remove security.txt.gz (diff) | |
download | euandre.org-020c1e77489b772f854bb3288b9c8d2818a6bf9d.tar.gz euandre.org-020c1e77489b772f854bb3288b9c8d2818a6bf9d.tar.xz |
git mv src/content/* src/content/en/
Diffstat (limited to 'src/content/blog/2018/08')
-rw-r--r-- | src/content/blog/2018/08/01/npm-ci-reproducibility.adoc | 147 |
1 files changed, 0 insertions, 147 deletions
diff --git a/src/content/blog/2018/08/01/npm-ci-reproducibility.adoc b/src/content/blog/2018/08/01/npm-ci-reproducibility.adoc deleted file mode 100644 index 76bd8e6..0000000 --- a/src/content/blog/2018/08/01/npm-ci-reproducibility.adoc +++ /dev/null @@ -1,147 +0,0 @@ -= Verifying "npm ci" reproducibility -:updatedat: 2019-05-22 - -:empty: -:npm-5: https://blog.npmjs.org/post/161081169345/v500 -:package-locks-old: https://docs.npmjs.com/files/package-locks -:package-lock: https://docs.npmjs.com/files/package-lock.json -:add-npm-ci: https://blog.npmjs.org/post/171556855892/introducing-npm-ci-for-faster-more-reliable -:cli-docs: https://docs.npmjs.com/cli/install#description -:tricky-issue: https://github.com/npm/npm/issues/17979#issuecomment-332701215 - -When {npm-5}[npm@5] came bringing {package-locks-old}[package-locks] with it, I -was confused about the benefits it provided, since running `npm install` more -than once could resolve all the dependencies again and yield yet another fresh -`package-lock.json` file. The message saying "you should add this file to -version control" left me hesitant on what to -do{empty}footnote:package-lock-message[ - {cli-docs}[documentation] claims `npm install` is driven by the existing - `package-lock.json`, but that's actually {tricky-issue}[a little bit tricky]. -]. - -However the {add-npm-ci}[addition of `npm ci`] filled this gap: it's a stricter -variation of `npm install` which guarantees that "{package-lock}[subsequent -installs are able to generate identical trees]". But are they really identical? -I could see that I didn't have the same problems of different installation -outputs, but I didn't know for *sure* if it was really identical. - -== Computing the hash of a directory's content - -:merkle-tree: https://en.wikipedia.org/wiki/Merkle_tree - -I quickly searched for a way to check for the hash signature of an entire -directory tree, but I couldn't find one. I've made a poor man's -{merkle-tree}[Merkle tree] implementation using `sha256sum` and a few piped -commands at the terminal: - -[source,sh] ----- -merkle-tree () { - dirname="${1-.}" - pushd "$dirname" - find . -type f | - sort | - xargs -I{} sha256sum "{}" | - sha256sum | - awk '{print $1}' - popd -} ----- - -Going through it line by line: - -* #1 we define a Bash function called `merkle-tree`; -* #2 it accepts a single argument: the directory to compute the merkle tree from - If nothing is given, it runs on the current directory (`.`); -* #3 we go to the directory, so we don't get different prefixes in `find`'s - output (like `../a/b`); -* #4 we get all files from the directory tree. Since we're using `sha256sum` to - compute the hash of the file contents, we need to filter out folders from it; -* #5 we need to sort the output, since different file systems and `find` - implementations may return files in different orders; -* #6 we use `xargs` to compute the hash of each file individually through - `sha256sum`. Since a file may contain spaces we need to escape it with - quotes; -* #7 we compute the hash of the combined hashes. Since `sha256sum` output is - formatted like `<hash> <filename>`, it produces a different final hash if a - file ever changes name without changing it's content; -* #8 we get the final hash output, excluding the `<filename>` (which is `-` in - this case, aka `stdin`). - -=== Positive points: - -. ignore timestamp: running more than once on different installation yields the - same hash; -. the name of the file is included in the final hash computation. - -=== Limitations: - -. it ignores empty folders from the hash computation; -. the implementation's only goal is to represent using a digest whether the - content of a given directory is the same or not. Leaf presence checking is - obviously missing from it. - -=== Testing locally with sample data - -[source,sh] ----- -mkdir /tmp/merkle-tree-test/ -cd /tmp/merkle-tree-test/ -mkdir -p a/b/ a/c/ d/ -echo "one" > a/b/one.txt -echo "two" > a/c/two.txt -echo "three" > d/three.txt -merkle-tree . # output is be343bb01fe00aeb8fef14a3e16b1c3d1dccbf86d7e41b4753e6ccb7dc3a57c3 -merkle-tree . # output still is be343bb01fe00aeb8fef14a3e16b1c3d1dccbf86d7e41b4753e6ccb7dc3a57c3 -echo "four" > d/four.txt -merkle-tree . # output is now b5464b958969ed81815641ace96b33f7fd52c20db71a7fccc45a36b3a2ae4d4c -rm d/four.txt -merkle-tree . # output back to be343bb01fe00aeb8fef14a3e16b1c3d1dccbf86d7e41b4753e6ccb7dc3a57c3 -echo "hidden-five" > a/b/one.txt -merkle-tree . # output changed 471fae0d074947e4955e9ac53e95b56e4bc08d263d89d82003fb58a0ffba66f5 ----- - -It seems to work for this simple test case. - -You can try copying and pasting it to verify the hash signatures. - -== Using `merkle-tree` to check the output of `npm ci` - -_I've done all of the following using Node.js v8.11.3 and npm@6.1.0_. - -In this test case I'll take the main repo of -https://lernajs.io/[Lerna]footnote:lerna-package-lock[ - Finding a big known repo that actually committed the `package-lock.json` file - was harder than I expected. -]: - -```bash -cd /tmp/ -git clone https://github.com/lerna/lerna.git -cd lerna/ -git checkout 57ff865c0839df75dbe1974971d7310f235e1109 -npm ci -merkle-tree node_modules/ # outputs 11e218c4ac32fac8a9607a8da644fe870a25c99821167d21b607af45699afafa -rm -rf node_modules/ -npm ci -merkle-tree node_modules/ # outputs 11e218c4ac32fac8a9607a8da644fe870a25c99821167d21b607af45699afafa -npm ci # test if it also works with an existing node_modules/ folder -merkle-tree node_modules/ # outputs 11e218c4ac32fac8a9607a8da644fe870a25c99821167d21b607af45699afafa -``` - -Good job `npm ci` :) - -#6 and #9 take some time to run (21 seconds in my machine), but this specific -use case isn't performance sensitive. The slowest step is computing the hash of -each individual file. - -== Conclusion - -`npm ci` really "generates identical trees". - -I'm not aware of any other existing solution for verifying the hash signature of -a directory. If you know any, shoot me an email, as I'd like to know it. - -== *Edit* - -2019-05-22: Fix spelling. |