Hacking around on VisiData auto-run commands

README.md

VisiData Auto-Run Commands

I've mucked around with the idea of auto-running commands when a sheet opens before. I don't remember which walls I hit, but saulpw/visidata#1681 got me curious to try the idea of a post-load hook in .visidatarc again.

The contents of post_load_hook.py could be dropped directly into a .visidatarc or kept in its own file and imported from .visidatarc.

This is just a sample of course, but seems to work for some common cases at least. If I try to bulk load a bunch of sheets and reload all of them simultaneously I do get this traceback which suggests I need to do something smarter:

 Traceback (most recent call last):                                                                                        ║
   File "/home/aj/.local/pipx/venvs/visidata/lib/python3.11/site-packages/visidata/basesheet.py", line 209, in execCommand ║
     vd.cmdlog.afterExecSheet(vd.activeSheet, escaped, err)                                                                ║
   File "/home/aj/.local/pipx/venvs/visidata/lib/python3.11/site-packages/visidata/macros.py", line 71, in afterExecSheet  ║
     cmdlog.afterExecSheet.__wrapped__(cmdlog, sheet, escaped, err)                                                        ║
   File "/home/aj/.local/pipx/venvs/visidata/lib/python3.11/site-packages/visidata/cmdlog.py", line 217, in afterExecSheet ║
     if not sheet.cmdlog.rows or vd.isLoggableCommand(vd.activeCommand.longname):                                          ║
                                                      ^^^^^^^^^^^^^^^^^^^^^^^^^                                            ║
 AttributeError: 'NoneType' object has no attribute 'longname'

But hey, omelettes and eggs and all that...

post_load_hook.py

import time
from functools import wraps

from visidata import asyncthread, vd, BaseSheet, UNLOADED
from visidata.features.unfurl import unfurl_col
from visidata.loaders.parquet import ParquetSheet
from visidata.pyobj import expand_cols_deep

def post_load(sheet):
    """Run some commands anytime a sheet loads

    Also maybe run some commands that are sheet-specific.
    This _could_ be fancier and probably smarter, but seems to
    work for the moment as-is.

    If it looks like the sheet is in UNLOADED status, try hooking
    post_load hooks up to sheet.reload instead.
    """
    if sheet.rows is UNLOADED:
        setup_post_load_hook(sheet, "reload")
        return
    if isinstance(sheet, ParquetSheet):
        vd.status("Do something parquet-specific")
    if sheet.name == 'c7n_cache':
        # Adapted from https://gist.github.com/ajkerrigan/1214d4632b9e46cfa77c024d7c12f23d
        # to unpickle/expand Cloud Custodian cache data on open
        import pickle

        key_col = sheet.colsByName['key']
        value_col = sheet.colsByName['value']
        vd.addGlobals({'pickle': pickle})
        key_col.setValuesFromExpr(sheet.rows, 'pickle.loads(key)')
        expand_cols_deep(sheet, [key_col], depth=1)
        key_col.hide()
        value_col.setValuesFromExpr(sheet.rows, 'pickle.loads(value)')
        new_sheet = unfurl_col(sheet, value_col)
        vd.push(new_sheet)
        new_sheet.colsByName['value_key'].hide()
        value_col = new_sheet.colsByName['value_value']
        value_col.name = 'value'
        expand_cols_deep(new_sheet, [value_col], depth=1)
        value_col.hide()
        new_sheet.execCommand("resize-cols-max")
        new_sheet.execCommand("go-leftmost")
    sheet.execCommand("go-top")
    sheet.execCommand("resize-cols-max")

def setup_post_load_hook(obj, func):
    """
    Set up a hook to run commands when a sheet finishes loading (ish).

    Plan A: Sheet is loading as soon as it's pushed. Wait until it looks
    like the load finished, and kick off some auto-commands.

    Plan B: Sheet hangs in UNLOADED status for a while. Figure that out
    later.
    """

    f = getattr(obj, func)

    @asyncthread
    def post_load_hook(*args, **kwargs):
        sheet = obj if isinstance(obj, BaseSheet) else args[0]
        time.sleep(.1)
        while {t.name for t in sheet.currentThreads} - {"post_load_hook"}:
            vd.status("waiting to execute post_load hook")
            time.sleep(.1)
        vd.status("running post_load hook")
        post_load(sheet)

    @wraps(f)
    def wrapper(*args, **kwargs):
        f(*args, **kwargs)
        post_load_hook(*args, **kwargs)

    setattr(obj, func, wrapper)
    vd.status(f"{obj.__class__.__name__}.{func}() wrapped to setup post-load hooks")

setup_post_load_hook(vd, "push")