Pin TF_PLUGIN_CACHE_DIR to a predictable path on terraformer (#274)#275
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Configure a shared Terraform provider plugin cache at a fixed path so provider binaries are stored once under a deterministic prefix instead of per-workdir .terraform/providers paths that vary run to run. This gives AWS Inspector EC2 scanning a single PREFIX anchor to suppress the provider-binary noise while still scanning the host's OS packages. New profile::terraformer::plugin_cache: - creates /var/cache/terraform/plugins (terraform won't create it itself) - exports TF_PLUGIN_CACHE_DIR via /etc/profile.d for login shells - makes the cache writable by the admin group (setgid + default POSIX ACL) so non-privileged admin users sharing the box can populate it Mirrored across the top-level, development, and sandbox module copies. Pairs with infrahouse/terraform-aws-terraformer#34. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
infrahouse8
approved these changes
Jun 24, 2026
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Closes #274.
Why
The terraformer host runs
terraformacross many working directories. By defaultterraform initdownloads provider binaries into each workdir's.terraform/providers/..., so the real Go binaries land at per-workdir paths that vary run to run.We want AWS Inspector EC2 scanning enabled on this host (to catch real OS-package CVEs) while suppressing only the noise from Terraform provider binaries. Inspector suppression filters match
file_pathwithEQUALS/PREFIX/NOT_EQUALSonly — no glob, noCONTAINS— so the provider binaries must sit under a single, stable prefix to be targetable.What
New
profile::terraformer::plugin_cache, included fromprofile::terraformer:/var/cache/terraform/plugins(Terraform won't create the cache dir itself).TF_PLUGIN_CACHE_DIRvia/etc/profile.d/terraform-plugin-cache.shfor login shells.admingroup —setgid+ a default POSIX ACL (d:g:admin:rwx), since terraform is run by non-privileged users in theadmingroup and setgid alone loses group-write on nested provider dirs under the default umask. Installs theaclpackage; thesetfaclexec is idempotent via agetfaclguard.Mirrored across the top-level, development, and sandbox module copies (matching the prior terraformer change in #229).
Verified on a live terraformer
TF_PLUGIN_CACHE_DIR=/var/cache/terraform/pluginsin a login shell./var/cache/terraform/pluginsisdrwxrwsr-x+groupadmin; nested provider dirs inherit setgid + the ACL.terraform init, real provider binaries live once under/var/cache/terraform/plugins/registry.terraform.io/...and every.terraform/providers/...entry in the workdir is a symlink back into the cache.Companion
Pairs with infrahouse/terraform-aws-terraformer#34 (make the Inspector EC2 exclusion opt-in, then suppress the provider-binary noise via this predictable path).
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