great-ai/docs/how-to-guides/large_file.md
2022-07-13 12:44:57 +02:00

114 lines
4.9 KiB
Markdown

# How to use LargeFile-s
The functions [save_model][great_ai.use_model] and [@use_model][great_ai.use_model] wrap LargeFile instances. Hence, besides configuring LargeFile, users have few reasons to use LargeFile-s directly.
## Motivation
Oftentimes, especially when working with data-heavy applications, large files can proliferate in a repository. Version controlling them is an obvious next step, however, GitHub's git LFS implementation [doesn't support deleting](https://docs.github.com/en/repositories/working-with-files/managing-large-files/removing-files-from-git-large-file-storage#git-lfs-objects-in-your-repository) large files, making it easy for them to eat-up the LFS quota and explode the size of your repos.
[DVC](https://dvc.org/) is a viable alternative, however, it requires users to learn to use one more CLI tool.
??? note "Using LargeFile-s directly (usually not needed)"
LargeFile doesn't require users to learn too much new. It is a nearly exact copy of the built-in `open()` function of Python with which users are certainly already familiar.
## Simple example
```python
from great_ai.large_file import LargeFileS3
LargeFileS3.configure_credentials({
"aws_region_name": "your_region_like_eu-west-2",
"aws_access_key_id": "YOUR_ACCESS_KEY_ID",
"aws_secret_access_key": "YOUR_VERY_SECRET_ACCESS_KEY",
"large_files_bucket_name": "create_a_bucket_and_put_its_name_here",
})
# Creates a new version and deletes the older version
# leaving the 3 most recently used intact
with LargeFileS3("test.txt", "w", keep_last_n=3) as f:
for i in range(100000):
f.write('test\n')
# By default the latest version is returned
# but an optional `version` keyword argument can be provided as well
with LargeFileS3("test.txt", "r") as f: #(1)
print(f.readlines()[0])
```
1. In this case, the latest version is already in the local cache, no download is required.
### More details
`LargeFile` behaves like an opened file (in the background it is a temp file after all). Binary reads and writes are supported along with the [different keywords `open()` accepts](https://docs.python.org/3/library/functions.html#open).
The local cache can be configured with these properties:
```python
LargeFileS3.cache_path = Path('.cache')
LargeFileS3.max_cache_size = "30 GB"
```
#### I only need a path
In case you only need a path to the "remote" file, this pattern can be applied:
```python
path_to_model = LargeFileS3("folder-of-my-bert-model", version=31).get()
```
> This will first download the file/folder into your local cache folder. Then, it returns a `Path` object to the local version. Which can be turned into a string with `str(path_to_model)`.
The same approach works for uploads:
```python
LargeFileS3("folder-of-my-bert-model").push('path_to_local/folder_or_file')
```
> This way both regular files and folders can be handled. The uploaded file is called **folder-of-my-bert-model**, the local name is ignored.
Lastly, all version of the remote object can be deleted by calling `LargeFileS3("my-file").delete()`. It will still reside in your local cache afterwards, its deletion will happen next time your local cache has to be pruned.
## From the command-line
The main reason for using the `large-file` or `python3 -m great_ai.large_file` commands is to upload or download models from the terminal. For example, when building a docker image, it is best-practice to cache the referred models.
### Setup
Create an .ini file (or use *~/.aws/credentials*). It may look like this:
```ini
aws_region_name = your_region_like_eu-west-2
aws_access_key_id = YOUR_ACCESS_KEY_ID
aws_secret_access_key = YOUR_VERY_SECRET_ACCESS_KEY
large_files_bucket_name = my_large_files
```
### Upload some files
```sh
large-file --backend s3 --secrets secrets.ini \
--push my_first_file.json folder/my_second_file my_folder
```
> Only the filename is used as the S3 name, the rest of the path is ignored.
!!! important "Using MongoDB"
The possible values for `--backend` are `s3`, `mongo`, and `local`. The latter doesn't need credentials, it only versions and stores your files in a local folder. MongoDB on the other hand requires a `mongo_connection_string` and a `mongo_database` to be specified. For storing large files, it uses the GridFS specification.
### Download some files to the local cache
This can be useful when building a Docker image for example. This way, the files can already reside inside the container and need not be downloaded later.
```sh
large-file --backend s3 --secrets ~/.aws/credentials \
--cache my_first_file.json:3 my_second_file my_folder:0
```
> Versions may be specified by using `:`-s.
### Delete remote files
```sh
large-file --backend s3 --secrets ~/.aws/credentials \
--delete my_first_file.json
```