Fix linux install failing

[ddelange]

Fixes #1865

$ TFLINT_VERSION=v0.48.0 curl -s https://raw.githubusercontent.com/ddelange/tflint/patch-1/install_linux.sh | bash
arch=amd64
os=linux_amd64
====================================================
Looking up the latest version ...
Downloading TFLint v0.48.0
Downloaded successfully
====================================================
Unpacking /tmp/tflint.UpItlTocXZ/tflint.zip ...
Archive:  /tmp/tflint.UpItlTocXZ/tflint.zip
  inflating: /tmp/tflint.UpItlTocXZ/tflint  
Installing /tmp/tflint.UpItlTocXZ/tflint to /usr/local/bin/ ...
'/tmp/tflint.UpItlTocXZ/tflint' -> '/usr/local/bin/tflint'
Cleaning temporary downloaded files directory /tmp/tflint.UpItlTocXZ ...
====================================================
Current tflint version
TFLint version 0.48.0
+ ruleset.terraform (0.4.0-bundled)

[bendrucker]

This creates a regression by removing a legitimate feature. It causes API requests that complete with non-2xx responses to not error. I'm going to decline this PR. You need to supply a sufficiently modern version of curl. We might accept a PR checking the cURL version to produce a clearer error but since that's not straightforward I'd have to see the code to decide on that tradeoff.

[bendrucker]

I guess I misread the original, sounds like you do have --fail in your cURL version. Not sure why it's not working as expected, but removing --fail as you've done here isn't right. If set -e changes the behavior over #!/bin/bash -e, that's weird but fine, happy to accept that change.

[ddelange]

Hi @bendrucker :wave:

This PR fixes two bugs:

• ~Adding --fail makes non 2xx responses fail silently (curl always exists 0, see issue), and erroneously allows the script to continue despite -e. That made the output of the script look very weird (see issue), because~ it then crashes on trying to unzip a file which was never downloaded. edit: see the next comment
• The script attempts to fetch latest version from github api, although I specified TFLINT_VERSION manually (see issue). Apparently github blocks unauthenticated api requests from the Bitbucket IPs, so this is the only way I can install tflint in CI. It's a blocker.

I removed -x again, which just makes the script more verbose by showing which commands are run, useful for debugging (docs). Using set is preferred over flags in shebang, ~mainly due to historical reasons I think~. edit: see the next comment

How does the diff look now?

[ddelange]

Ah, my curl --help posted in the issue was a bit unclear. Their man is clearer about it. Looks like it's indeed safe to have it for the file transfer. I have reverted the curl commands.

So then, the reason for the script continuing despite the errors, is that the install script is piped to plain bash. So the shebang is ignored :) The shebang is to help your shell identify how to execute this file if you made the file executable and you simply try running it like $ install_script.sh instead of $ bash install_script.sh.

Final diff:

• using set instead of shebang
• using bash variable substitution for TFLINT_VERSION

[bendrucker]

Ah that makes sense. PR welcome to fix that, otherwise I'll get to it eventually.