In-Orbit Python Environment Setup

All payloads include the software and libraries to compile C & C++ applications. This environment is not well suited to the iterative process usually needed due to the time taken to upload files, schedule activities, and wait for the results to appear in the bucket. Where dependent packages are needed, large uploads will require additional time to upload.

Developers should consider using the cross compiler if possible.

The ISL tutorial requires the python module zfec. This module has a native C library that is built at installation time by setuptools. The SABERTOOTH, SDR, IPI payloads require further setup if the developer plans to deploy python modules that have a C/C++ native build step. This walkthrough can be adapted for any Linux distro package or python module.

Packages

• Python 3.6.9 headers (43 MB)
• Python3 pip v20.3.4 (1.7 MB)
• Python3 setuptools v59.6.0 (952 KB)
• pyutil 3.3.0 Python module (292 KB)
• zfec 1.5.1 Python module (70 KB)

Uploading each package would take quite a while. To reduce the time required to upload the packages the following steps are taken:

1. Remove any files in packages that are not needed
2. Re-pack all packages into a single archive for better compression
3. Use xz/lzma compression to further reduce the size

Install Script

Steps:

1. Locate tarball at end of install file
2. Extract the tarball to CWD
3. Recreate wheel packages for python
4. Move include files to /persist/usr/include
5. pip install modules

See the install.in input script in github.

Create Deploy Package

Steps:

1. Download packages locally
2. Extract package contents
3. Select minimal file set
4. Build a single xz compressed tarball
5. Append the tarball to a bash install script

See the create_package script in github.

Deploy Script

Deployment is a 2-step process of uploading the install file and executing it on the payload. Below are the steps for the SABERTOOTH payload. All steps should be repeated for the SDR and IPI if required.

Upload Script

HOST="https://api.orb.spire.com"
AUTH_HEADER="Authorization: Bearer YOUR_AUTH_TOKEN"
SAT_ID="YOUR_SAT_ID"

SATELLITE_ID="satellite_id=SAT_ID"
PAYLOAD="payload=SABERTOOTH"
DESTINATION_PATH="destination_path=/persist/bin/py-install"
EXECUTABLE="executable=true"
QUERY_PARAMS="${SATELLITE_ID}&${PAYLOAD}&${DESTINATION_PATH}&${EXECUTABLE}"

curl -X POST ${HOST}/tasking/upload?${QUERY_PARAMS} \
-H "${AUTH_HEADER}"  \
-F "file=@install"

Since the file is a non-trivial size of around 1.7 MB, multiple contacts will likely be needed.

Run Script

Add a PAYLOAD_SABERTOOTH window to the schedule for in 24 hours (86400 seconds). 24 hours was chosen to give the install script enough time to upload.

START=$(( `date -u +'%s'` + 86400 ))

curl -X POST ${HOST}/tasking/window \
-H "${AUTH_HEADER}" \
-H "Content-Type: application/json" \
-d @- << EOF
{
    "type": "PAYLOAD_SABERTOOTH",
    "satellite_id": "${SAT_ID}",
    "start": ${START},
    "duration": 60,
    "parameters": {
        "user_command": {
            "executable": "/persist/bin/py-install",
            "executable_arguments": ["/persist"]
        }
    }
}
EOF

Review Deploy Log

$ aws s3 ls --recursive s3://user-s3-bucket/a/directory/${SAT_ID}/downlink/

$ aws s3 cp s3://user-s3-bucket/a/directory/${SAT_ID}/downlink/2021/09/06/20210906T043229Z_py-install-2022_01_06_15_02_05.log -

Response:

2021-09-06 04:32:29          0 2021/
2021-09-06 04:32:29          0 2021/09/
2021-09-06 04:32:29          0 2021/09/06/
2021-09-06 04:32:29       5131 2021/09/06/20210906T043229Z_py-install-2022_01_06_15_02_05.log

<install log contents....>