Add managed crontab support

This commit is contained in:
Tim Van Baak 2023-06-21 18:32:44 -07:00
parent 53740655b6
commit 312e231ea6
7 changed files with 126 additions and 11 deletions

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@ -41,17 +41,20 @@ intake
},
"env": {
"...": "..."
}
},
"cron": "* * * * *"
}
```
Each key under `action` defines an action that can be taken for the source. `action` must be present with a `fetch` action. `env` is optional.
Each key under `action` defines an action that can be taken for the source. A minimal `intake.json` must contain a `fetch` action with an `exe`. All other configs are optional.
The `fetch` action is executed by `intake update`. All other actions are executable with `intake action`. `intake crontab` will create a crontab entry for each source with a `cron` config defined. The value of `cron` is the crontab spec according to which the source should be updated.
## Interface for source programs
Intake interacts with sources by executing the actions defined in the source's `intake.json`. The `fetch` action is required and used to check for new feed items.
Intake interacts with sources by executing the actions defined in the source's `intake.json`. The `fetch` action is required and used to check for new feed items when `intake update` is executed.
When any action is executed, intake executes the `exe` program for the action with the corresponding `args` as arguments. The process's working directory is set to the source's folder, i.e. the folder containing `intake.json`. The process's environment is as follows:
To execute an action, intake executes the `exe` program for the action with the corresponding `args` (if present) as arguments. The process's working directory is set to the source's folder, i.e. the folder containing `intake.json`. The process's environment is as follows:
* intake's environment is inherited.
* `STATE_PATH` is set to the absolute path of `state`.

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@ -4,5 +4,6 @@
"exe": "currenttime.sh",
"args": []
}
}
},
"cron": "* * * * *"
}

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@ -8,17 +8,16 @@
isNormalUser = true;
password = "alpha";
uid = 1000;
packages = [ pkgs.intake ];
};
users.users.bob = {
isNormalUser = true;
password = "beta";
uid = 1001;
packages = [ pkgs.intake ];
};
# Put intake on both users' PATH
environment.systemPackages = [ pkgs.intake ];
# Set up intake for both users with an entry point at port 8080
services.intake = {
listen.port = 8080;

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@ -7,7 +7,16 @@ import json
import os
import time
from flask import Flask, render_template, request, jsonify, abort, redirect, url_for, current_app
from flask import (
Flask,
render_template,
request,
jsonify,
abort,
redirect,
url_for,
current_app,
)
from intake.core import intake_data_dir
from intake.source import LocalSource, execute_action, Item

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@ -11,11 +11,11 @@ import subprocess
import sys
from intake.core import intake_data_dir
from intake.crontab import update_crontab_entries
from intake.source import fetch_items, LocalSource, update_items, execute_action
from intake.types import InvalidConfigException, SourceUpdateException
def cmd_edit(cmd_args):
"""Open a source's config for editing."""
parser = argparse.ArgumentParser(
@ -296,6 +296,24 @@ def cmd_passwd(cmd_args):
return 0
def cmd_crontab(cmd_args):
"""Update cron with configured source cron entries."""
parser = argparse.ArgumentParser(
prog="intake crontab",
description=cmd_crontab.__doc__,
)
parser.add_argument(
"--data",
"-d",
help="Path to the intake data directory containing source directories",
)
args = parser.parse_args(cmd_args)
data_path: Path = Path(args.data) if args.data else intake_data_dir()
update_crontab_entries(data_path)
return 0
def cmd_run(cmd_args):
"""Run the default Flask server."""
parser = argparse.ArgumentParser(

82
intake/crontab.py Normal file
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@ -0,0 +1,82 @@
from pathlib import Path
import os
import subprocess
from intake.source import LocalSource
INTAKE_CRON_BEGIN = "### begin intake-managed crontab entries"
INTAKE_CRON_END = "### end intake-managed crontab entries"
def get_desired_crons(data_path: Path):
"""
Get a list of sources and crontab specs from the data directory.
"""
for child in data_path.iterdir():
if not (child / "intake.json").exists():
continue
source = LocalSource(data_path, child.name)
config = source.get_config()
if cron := config.get("cron"):
yield f"{cron} . /etc/profile; intake update -s {source.source_name}"
def update_crontab_entries(data_path: Path):
"""
Update the intake-managed section of the user's crontab.
"""
# If there is no crontab command available, quit early.
crontab_exists = subprocess.run(["command", "-v" "crontab"], shell=True)
if crontab_exists.returncode:
print("Could not update crontab")
return
# Get the current crontab
get_crontab = subprocess.run(
["crontab", "-e"],
env={**os.environ, "EDITOR": "cat"},
stdout=subprocess.PIPE,
stderr=subprocess.DEVNULL,
)
crontab_lines = get_crontab.stdout.decode("utf-8").splitlines()
# Splice the intake crons into the crontab
new_crontab_lines = []
section_found = False
in_section = False
for i in range(len(crontab_lines)):
if not section_found and crontab_lines[i] == INTAKE_CRON_BEGIN:
section_found = True
in_section = True
# Open the section and add everything
new_crontab_lines.append(INTAKE_CRON_BEGIN)
new_crontab_lines.extend(get_desired_crons(data_path))
elif crontab_lines[i] == INTAKE_CRON_END:
new_crontab_lines.append(INTAKE_CRON_END)
in_section = False
elif not in_section:
new_crontab_lines.append(crontab_lines[i])
# If the splice mark was never found, append the whole section to the end
if not section_found:
new_crontab_lines.append(INTAKE_CRON_BEGIN)
new_crontab_lines.extend(get_desired_crons(data_path))
new_crontab_lines.append(INTAKE_CRON_END)
# Save the updated crontab
new_crontab: bytes = "\n".join(new_crontab_lines).encode("utf8")
save_crontab = subprocess.Popen(
["crontab", "-"],
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
)
(stdout, stderr) = save_crontab.communicate(new_crontab)
for line in stdout.decode("utf8").splitlines():
print("[stdout]", line)
for line in stderr.decode("utf8").splitlines():
print("[stderr]", line)

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@ -105,6 +105,9 @@ in {
};
in mkMerge (map addPackagesToUser enabledUserNames);
# Enable cron
services.cron.enable = true;
# Define a user service for each configured user
systemd.services =
let