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https://github.com/krunch3r76/gc__gvmi_hash
python script to output the Requestor's gvmi image hash as seen on the Golem repository
https://github.com/krunch3r76/gc__gvmi_hash
golem
Last synced: 8 days ago
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python script to output the Requestor's gvmi image hash as seen on the Golem repository
- Host: GitHub
- URL: https://github.com/krunch3r76/gc__gvmi_hash
- Owner: krunch3r76
- License: gpl-3.0
- Created: 2021-05-26T02:10:23.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2022-07-07T04:56:41.000Z (about 2 years ago)
- Last Synced: 2024-01-24T03:42:06.006Z (9 months ago)
- Topics: golem
- Language: Python
- Homepage:
- Size: 104 KB
- Stars: 2
- Watchers: 1
- Forks: 2
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# gc__gvmi_hash
Summary: computes the hash of a gvmi image file.
Extra: optionally queries the Golem network to confirm that gvmi image is available from golem's central repository (i.e. to see if the hash link has been created)
# Usage:
```
git clone https://github.com/krunch3r76/gc__gvmi_hash.git
python3 gc__gvmi_hash/gc__gvmi_hash.py
```
## Example:BASH
```bash
(cracker-venv)$ git clone https://github.com/krunch3r76/gc__gvmi_hash.git
(cracker-venv)$ alias gvmi_hash="python3 $PWD/gc__gvmi_hash/gc__gvmi_hash.py" #BASH alias
(cracker-venv)$ krunch3r@crystalcavern:~/hash-cracker$ gvmi_hash *.gvmi
SHA3-224(docker-hash-cracker-latest-363b2e9df2.gvmi)= e1a95ab266977b857ae1c59942ebc7384a72359840b452c2e5293737
SHA3-224(docker-hash-cracker-latest-e93d21fba0.gvmi)= 4c9778760794a5fa6b8461ed2654c09cbc20f16edd3ec687c3289db8
```
## Example:Powershell
```powershell
cracker-venv > git clone https://github.com/krunch3r76/gc__gvmi_hash.git
cracker-venv > $gvmi_hash="${PWD}\gc__gvmi_hash\gc__gvmi_hash.py"
cracker-venv > python $gvmi_hash docker-hash-cracker-latest-363b2e9df2.gvmi
SHA3-224(docker-hash-cracker-latest-363b2e9df2.gvmi)= e1a95ab266977b857ae1c59942ebc7384a72359840b452c2e5293737
```
### Example:Powershell: alternatively edit $PROFILE
set $gvmi_hash to absolute path to\gc__gvmi_hash\gc__gvmi_hash.py
example $profile
```
oh-my-posh init pwsh --config $env:POSH_THEMES_PATH/space.omp.json | Invoke-Expression
$gvmi_hash="C:\Users\krunch3r\golem\gc__gvmi_hash\gc__gvmi_hash.py"
```
```powershell
somewhere > . $profile
cracker-venv > python $gvmi_hash docker-hash-cracker-latest-363b2e9df2.gvmi
SHA3-224(docker-hash-cracker-latest-363b2e9df2.gvmi)= e1a95ab266977b857ae1c59942ebc7384a72359840b452c2e5293737
```
# Extra Usage (Linux):
```bash
$ alias gvmi_hash="python3 $PWD/gc__gvmi_hash/gc__gvmi_hash.py" #BASH alias
$ gvmi_hash --check-hash-link 4c9778760794a5fa6b8461ed2654c09cbc20f16edd3ec687c3289db8
The link exists on the central repository.
$ gvmi_hash docker-hash-cracker-latest-e93d21fba0.gvmi | cut -f2 -d ' ' | gvmi_hash --check-hash-link-stdin
The link exists on the central repository.
```
# Problem:
The gvmkit-build Python package/script outputs the hash of a gvmi image only after its initial push operation. However, a Requestor is required to provide the pushed image hash in its requestor script, and if lost, has no means provided by gvmkit-build to re-output the image hash. Additionally, the current Golem documentation neither specifies the hashing algorithm used (sha3-224) nor suggests a tool for recomputation.
The supplied gv__gvmi_hash.py solves a lost hash problem by hashing the input image file using the same algorithm as, and with no additional runtime dependencies than those already satisfied by, the gvmkit-build package -- namely the Python Standard Library + OpenSSL libraries.
Note, the script is equivalent to invoking `openssl dgst -sha3-224 ` on systems where openssl executables have been installed. Also, the hash algorithm is indeed SHA3-224 and the reader is encouraged to see the code in gvmkit-build itself (viz Credits) to convince oneself of this.
--Note: to understand better what problem this script solves, it is recommended the reader follow the Provider Flash Tutorial (Python) at https://handbook.golem.network/requestor-tutorials/flash-tutorial-of-requestor-development. --
## NOTE:
The script's extra functionality (viz Extra Usage) to query the repo for the hash link makes an outside network connection. The routine is safe (HTTP/1.1 HEAD request), short, and can be quickly audited for peace of mind in the context of security concerns. viz (__check_for_hash_link in gc__gvmi_has.py)
# Credits:
Adapted from the source code in the Python package gvmkit-build, which is viewable in the tarbell via https://pypi.org/project/gvmkit-build/#files (file: repo.py, function: upload_image). Formatting of output should be credited to openssl.org.
# Tips:
Consider placing community scripts on linux such as this in $HOME/.local/bin/golem-community and adding it to your path. You may also consider adding said community scripts path to the environment variable PYTHONPATH and calling from gc__gvmi_hash import gc__gvmi_hash in order to utilize the function from within scripts, e.g. requestor.py.
# Additional:
## primary function inputs,process,and outputs:
```python
def gc__gvmi_hash(filename: str): # gc for golem community
MEBIBYTES=1024*1024 # one mebibyte ie megabyte, always a multiple of typical block sizes 4096,8192
# input: path to file as string
# pre: file is readable, MEBIBYTES defined
# process:
# open gvmi image
# on each chunk
# send to hasher
# query hasher
# output: hash as string
# post: none
# notes: additional details of the hashlib implementation may be discoverable via https://www.openssl.org/docs/manmaster/man3/EVP_DigestInit.html
```
# Alternatives:
Besides the openssl dgst command mentioned in the problem statement, a simple command line tool and call may be preferred if extra features of gc__gvmi_hash are not needed. See https://handbook.golem.network/requestor-tutorials/vm-runtime/self-hosted-vm-images for details.