falco

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    "go"
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  "desc": "VCL parser and linter optimized for Fastly",
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  "enrichment_fetched_at": "2026-06-20T23:37:30+00:00",
  "first_seen": "2026-06-20T23:34:18+00:00",
  "full_name": "falco",
  "github_default_branch": "main",
  "github_last_commit_at": "2026-06-19T11:18:43Z",
  "github_readme_excerpt": "\u003cp align=\"center\"\u003e\n\u003cimg src=\"https://user-images.githubusercontent.com/1000401/225396918-6490ea38-6883-434a-ac1f-e8b6188ec58b.png\" width=\"320\" /\u003e\n\u003c/p\u003e\n\u003cp align=\"center\"\u003e\u003ca href=\"https://www.fastly.com\"\u003eFastly\u003c/a\u003e VCL developer tool\u003c/p\u003e\n\n----\n\n[![Go Reference](https://pkg.go.dev/badge/github.com/ysugimoto/falco.svg)](https://pkg.go.dev/github.com/ysugimoto/falco)\n![Build](https://github.com/ysugimoto/falco/actions/workflows/build.yml/badge.svg)\n\n\n## Disclaimer\n\nThis is a VCL parser, but dedicated to Fastly\u0027s VCL (version 2.x), so we don\u0027t care about the latest Varnish (7.x or later) syntax.\nThe Varnish may have additional syntax, builtin function, predefined variables, but this tool may not parse correctly.\n\nAdditionally, Fastly provides its special builtin function, predefined variables. It\u0027s not compatible with Varnish.\nBut this tool is optimized for them, we could parse and lint/execute their declarations.\n\n## Motivation\n\nFastly is a really fantastic CDN, but sometimes we have problems with deployment operations.\nOn deploy custom VCL to the Fastly, VCLs are validated when activating a new service version.\nTypically our deployment flow using custom VCLs is following:\n\n1. Clone active service and create new version\n2. Delete existing custom VCLs\n3. Upload new VCL files to the Fastly\n4. Activate new device version **\u003c= Validate VCLs on the Fastly cloud**\n\nAbove flows take a time, and then if we have some mistakes on VCL e.g. missing semicolon X(, the deployment will fail.\nAdditionally, unnecessary service versions will be created by our trivial issue.\n\nTo solve them, we made a Fastly dedicated tool to develop custom VCLs locally.\n\n## Installation\n\nDownload binary from [releases page](https://github.com/ysugimoto/falco/releases) according to your platform and place it under the `$PATH`, or you can install via [Homebrew](https://brew.sh/):\n\n```shell\n$ brew install falco\n```\n\nYou can compile this project by yourself with:\n\n```shell\ngo install github.com/ysugimoto/falco/",
  "github_repo": "ysugimoto/falco",
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  "github_topics": [
    "debugger",
    "fastly",
    "formatter",
    "golang",
    "interpreter",
    "linter",
    "parser",
    "testing",
    "vcl"
  ],
  "homepage": "https://github.com/ysugimoto/falco",
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  "last_seen": "2026-06-20T23:34:18+00:00",
  "license": "MIT",
  "llm_generated_at": null,
  "llm_model": null,
  "name": "falco",
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  "raw_hash": "5caf08a246918143",
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  "ruby_source_path": "Formula/f/falco.rb",
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  "version_stable": "2.3.0",
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