Security & Robustness Improvements

[solarisfire]

This release focuses on hardening, correctness, and operator clarity while preserving all existing behaviour, data formats, and upload cadence.

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JSON handling

Changed

• All JSON payloads are now constructed using jq instead of shell string concatenation.

Why

• Prevents malformed JSON when upstream commands return partial output, non-JSON text, or unexpected characters.
• Ensures all values (API key, server names, telemetry data) are safely escaped.
• Eliminates injection and formatting edge cases.

Behaviour

• Payload schema and content remain unchanged when inputs are valid.

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Ping server handling

Changed

• Server lists are parsed safely and robustly:
  • Supports both JSON arrays and whitespace-separated responses.
  • Server entries are handled as complete strings rather than shell-split tokens.
• Server strings are used directly as JSON object keys via jq.

Why

• Avoids shell word-splitting bugs.
• Prevents malformed JSON if server names contain special characters.
• Makes the script resilient to future API format changes.

Behaviour

• Ping logic, parallelism, and results are unchanged.

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curl hardening

Changed

• Introduced shared curl_json and curl_post_json helpers with:
  • Explicit connection and total timeouts
  • Retry logic for transient network failures
  • Proper failure on HTTP error responses
  • Consistent headers and compressed transfers

Why

• Ensures network failures fail fast and predictably.
• Prevents silent success on HTTP 4xx/5xx responses.
• Centralises network behaviour for consistency.

Behaviour

• Endpoints, payloads, and timing remain unchanged.

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Script locking

Changed

• Replaced PID file logic in /tmp with an advisory lock using flock.

Why

• Avoids stale PID files after crashes or power loss.
• Prevents accidental concurrent execution.
• Removes reliance on predictable temporary filenames.

Behaviour

• Single-instance enforcement remains unchanged.

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Dishy telemetry collection

Changed

• grpcurl execution now:
  • Uses timeout -k to guarantee termination
  • Explicitly closes stdin to avoid blocking edge cases
  • Validates JSON output before accepting it
  • Provides clear console feedback on completion

Why

• Prevents perceived hangs during Dishy data collection.
• Ensures misbehaving gRPC calls cannot stall the main loop.
• Improves operator visibility without changing logic.

Behaviour

• Collection frequency and data content remain unchanged.

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Upload execution

Changed

• Removed invalid use of timeout around shell functions.
• Relied on curl’s built-in timeout controls instead.

Why

• timeout can only execute external binaries, not shell functions.
• Curl already enforces strict execution limits.

Behaviour

• Upload timing and failure handling remain unchanged.

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Validation and execution safety

Changed

• Enabled set -euo pipefail.
• Added validation for interval arguments.
• Ensured optional data sections always produce valid JSON objects.

Why

• Prevents undefined variables and partial state propagation.
• Ensures failures are detected early and handled cleanly.
• Improves long-running stability.

Behaviour

• Normal operation remains unchanged.
• Errors now fail fast and explicitly.

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Explicitly unchanged behaviour

• Low-resolution upload cadence (epoch-aligned modulo timing)
• High-resolution upload cadence (15-second alignment)
• Command-line API key usage
• Parallel ping behaviour
• Data schema sent to starlinkstatus.space

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[Tysonpower]

Thanks for the PR! Are there new dependencies that are needed for using this new Script?

[solarisfire]

Thanks! Yes — this update introduces one new required dependency:

jq (used to construct the JSON payload safely instead of string concatenation)

Everything else is unchanged. The locking mechanism now uses flock, but on Raspberry Pi OS / Debian that comes from util-linux, which is installed by default on basically all systems (so no extra install step in most cases).

All existing optional dependencies remain the same:

speedtest (only if --speedtest)

grpcurl (only if --dishy)

GNU parallel (already required)