html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,issue,performed_via_github_app
https://github.com/simonw/datasette/pull/1870#issuecomment-1295667649,https://api.github.com/repos/simonw/datasette/issues/1870,1295667649,IC_kwDOBm6k_c5NOlHB,536941,2022-10-29T00:52:43Z,2022-10-29T00:53:43Z,CONTRIBUTOR,"> Are you saying that I can build a container, but then when I run it and it does `datasette serve -i data.db ...` it will somehow modify the image, or create a new modified filesystem layer in the runtime environment, as a result of running that `serve` command?
Somehow, `datasette serve -i data.db` will lead to the `data.db` being modified, which will trigger a [copy-on-write](https://docs.docker.com/storage/storagedriver/#the-copy-on-write-cow-strategy) of `data.db` into the read-write layer of the container.
I don't understand **how** that happens.
it kind of feels like a bug in sqlite, but i can't quite follow the sqlite code.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1426379903,
https://github.com/simonw/datasette/pull/1870#issuecomment-1295660092,https://api.github.com/repos/simonw/datasette/issues/1870,1295660092,IC_kwDOBm6k_c5NOjQ8,9599,2022-10-29T00:25:26Z,2022-10-29T00:25:26Z,OWNER,"Saw your comment here too: https://github.com/simonw/datasette/issues/1480#issuecomment-1271101072
> switching from `immutable=1` to `mode=ro` completely addressed this. see https://github.com/simonw/datasette/issues/1836#issuecomment-1271100651 for details.
So maybe we need a special case for containers that are intended to be run using Docker - the ones produced by `datasette package` and `datasette publish cloudrun`? Those are cases where the `-i` option should actually be opened in read-only mode, not immutable mode.
Maybe a `datasette serve --irw data.db` option for opening a file in immutable-but-actually-read-only mode? Bit ugly though.
I should run some benchmarks to figure out if `immutable` really does offer significant performance benefits.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1426379903,
https://github.com/simonw/datasette/pull/1870#issuecomment-1295657771,https://api.github.com/repos/simonw/datasette/issues/1870,1295657771,IC_kwDOBm6k_c5NOisr,9599,2022-10-29T00:19:03Z,2022-10-29T00:19:03Z,OWNER,"Just saw your comment here: https://github.com/simonw/datasette/issues/1836#issuecomment-1272357976
> when you are running from docker, you **always** will want to run as `mode=ro` because the same thing that is causing duplication in the inspect layer will cause duplication in the final container read/write layer when `datasette serve` runs.
I don't understand this. My mental model of how Docker works is that the image itself is created using `docker build`... but then when the image runs later on (`docker run`) the image itself isn't touched at all.
Are you saying that I can build a container, but then when I run it and it does `datasette serve -i data.db ...` it will somehow modify the image, or create a new modified filesystem layer in the runtime environment, as a result of running that `serve` command?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1426379903,
https://github.com/simonw/datasette/pull/1870#issuecomment-1294285471,https://api.github.com/repos/simonw/datasette/issues/1870,1294285471,IC_kwDOBm6k_c5NJTqf,536941,2022-10-28T01:06:03Z,2022-10-28T01:06:03Z,CONTRIBUTOR,"as far as i can tell, [this is where the ""immutable"" argument is used](https://github.com/sqlite/sqlite/blob/c97bb14fab566f6fa8d967c8fd1e90f3702d5b73/src/pager.c#L4926-L4931) in sqlite:
```c
pPager->noLock = sqlite3_uri_boolean(pPager->zFilename, ""nolock"", 0);
if( (iDc & SQLITE_IOCAP_IMMUTABLE)!=0
|| sqlite3_uri_boolean(pPager->zFilename, ""immutable"", 0) ){
vfsFlags |= SQLITE_OPEN_READONLY;
goto act_like_temp_file;
}
```
so it does set the read only flag, but then has a goto.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1426379903,
https://github.com/simonw/datasette/pull/1870#issuecomment-1294238862,https://api.github.com/repos/simonw/datasette/issues/1870,1294238862,IC_kwDOBm6k_c5NJISO,22429695,2022-10-27T23:44:25Z,2022-10-27T23:44:25Z,NONE,"# [Codecov](https://codecov.io/gh/simonw/datasette/pull/1870?src=pr&el=h1&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Simon+Willison) Report
Base: **92.55**% // Head: **92.55**% // No change to project coverage :thumbsup:
> Coverage data is based on head [(`4faa4fd`)](https://codecov.io/gh/simonw/datasette/pull/1870?src=pr&el=desc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Simon+Willison) compared to base [(`bf00b0b`)](https://codecov.io/gh/simonw/datasette/commit/bf00b0b59b6692bdec597ac9db4e0b497c5a47b4?el=desc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Simon+Willison).
> Patch has no changes to coverable lines.
Additional details and impacted files
```diff
@@ Coverage Diff @@
## main #1870 +/- ##
=======================================
Coverage 92.55% 92.55%
=======================================
Files 35 35
Lines 4432 4432
=======================================
Hits 4102 4102
Misses 330 330
```
| [Impacted Files](https://codecov.io/gh/simonw/datasette/pull/1870?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Simon+Willison) | Coverage Δ | |
|---|---|---|
| [datasette/app.py](https://codecov.io/gh/simonw/datasette/pull/1870/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Simon+Willison#diff-ZGF0YXNldHRlL2FwcC5weQ==) | `94.30% <ø> (ø)` | |
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