Added support for terraform_docs for Terraform 0.12 (#45)

Author: antonbabenko

README.md

@@ -6,10 +6,10 @@
 
 ### Step 1
 
-On MacOSX install the pre-commit package
+On MacOSX install the `pre-commit` and `awk` (required for Terraform 0.12) package
 
 ```bash
-brew install pre-commit
+brew install pre-commit awk
 ```
 
 For other operating systems check the [official documentation](http://pre-commit.com/#install)
@@ -21,10 +21,10 @@ Step into the repository you want to have the pre-commit hooks installed and run
 ```bash
 cat <<EOF > .pre-commit-config.yaml
 - repo: git://github.com/antonbabenko/pre-commit-terraform
-  rev: v1.12.0
+  rev: v1.13.0
   hooks:
     - id: terraform_fmt
-    # - id: terraform_docs # terraform-docs is not working with Terraform 0.12 yet (read note in README)
+    - id: terraform_docs
 EOF
 ```
 
@@ -73,7 +73,7 @@ Check the [source file](https://github.com/antonbabenko/pre-commit-terraform/blo
 
 1. It is possible to pass additional arguments to shell scripts when using `terraform_docs` and `terraform_docs_without_aggregate_type_defaults`. Send pull-request with the new hook if there is something missing.
 
-1. `terraform-docs` is not working with Terraform 0.12 yet (see [issue #62](https://github.com/segmentio/terraform-docs/issues/62)), so remember to disable `terraform_docs`, `terraform_docs_replace` and `terraform_docs_without_aggregate_type_defaults` hooks in your `.pre-commit-config.yaml`
+1. `terraform-docs` works with Terraform 0.12 but support is hackish (it requires `awk` to be installed) and may contain bugs. You can follow the native support of Terraform 0.12 in `terraform-docs` in [issue #62](https://github.com/segmentio/terraform-docs/issues/62).
 
 ## Notes for developers
 

terraform_docs.sh

@@ -25,12 +25,25 @@ main() {
     esac
   done
 
-  terraform_docs "$args" "$files"
+  local hack_terraform_docs=$(terraform version | head -1 | grep -c 0.12)
+
+  if [[ "$hack_terraform_docs" == "1" ]]; then
+    which awk 2>&1 >/dev/null || ( echo "awk is required for terraform-docs hack to work with Terraform 0.12"; exit 1)
+
+    TMP_AWK_FILE="$(mktemp --tmpdir terraform-docs-XXXXXXXXXX.awk)"
+    terraform_docs_awk $TMP_AWK_FILE
+    terraform_docs "$TMP_AWK_FILE" "$args" "$files"
+    rm -f "$TMP_AWK_FILE"
+  else
+    terraform_docs "0" "$args" "$files"
+  fi
+
 }
 
 terraform_docs() {
-  readonly args="$1"
-  readonly files="$2"
+  readonly terraform_docs_awk_file="$1"
+  readonly args="$2"
+  readonly files="$3"
 
   declare -a paths
   declare -a tfvars_files
@@ -62,7 +75,14 @@ terraform_docs() {
       continue
     fi
 
+  if [[ "$terraform_docs_awk_file" == "0" ]]; then
     terraform-docs $args md ./ > "$tmp_file"
+  else
+    TMP_FILE="$(mktemp --tmpdir terraform-docs-XXXXXXXXXX.tf)"
+    awk -f "$terraform_docs_awk_file" ./*.tf > "$TMP_FILE"
+    terraform-docs $args md "$TMP_FILE" > "$tmp_file"
+    rm -f "$TMP_FILE"
+  fi
 
     # Replace content between markers with the placeholder - https://stackoverflow.com/questions/1212799/how-do-i-extract-lines-between-two-line-delimiters-in-perl#1212834
     perl -i -ne 'if (/BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK/../END OF PRE-COMMIT-TERRAFORM DOCS HOOK/) { print $_ if /BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK/; print "I_WANT_TO_BE_REPLACED\n$_" if /END OF PRE-COMMIT-TERRAFORM DOCS HOOK/;} else { print $_ }' "$text_file"
@@ -76,6 +96,93 @@ terraform_docs() {
   done
 }
 
+terraform_docs_awk() {
+  readonly output_file=$1
+
+  cat <<"EOF" > $output_file
+# This script converts Terraform 0.12 variables/outputs to something suitable for `terraform-docs`
+# As of terraform-docs v0.6.0, HCL2 is not supported. This script is a *dirty hack* to get around it.
+# https://github.com/segmentio/terraform-docs/
+# https://github.com/segmentio/terraform-docs/issues/62
+
+{
+  if ( /\{/ ) {
+    braceCnt++
+  }
+
+  if ( /\}/ ) {
+    braceCnt--
+  }
+
+  # [START] variable or output block started
+  if ($0 ~ /(variable|output) "(.*?)"/) {
+    # [CLOSE] "default" block
+    if (blockDefCnt > 0) {
+      blockDefCnt = 0
+    }
+    blockCnt++
+    print $0
+  }
+
+  # [START] multiline default statement started
+  if (blockCnt > 0) {
+    if ($1 == "default") {
+      print $0
+      if ($NF ~ /[\[\(\{]/) {
+        blockDefCnt++
+        blockDefStart=1
+      }
+    }
+  }
+
+  # [PRINT] single line "description"
+  if (blockDefCnt == 0) {
+    if ($1 == "description") {
+      # [CLOSE] "default" block
+      if (blockDefCnt > 0) {
+        blockDefCnt = 0
+      }
+      print $0
+    }
+  }
+
+  # [PRINT] single line "type"
+  if (blockCnt > 0) {
+    if ($1 == "type" ) {
+      # [CLOSE] "default" block
+      if (blockDefCnt > 0) {
+        blockDefCnt = 0
+      }
+      type=$3
+      if (type ~ "object") {
+        print "  type = \"object\""
+      } else {
+        print "  type = \"" $3 "\""
+      }
+    }
+  }
+
+  # [CLOSE] variable/output block
+  if (blockCnt > 0) {
+    if (braceCnt == 0 && blockCnt > 0) {
+      blockCnt--
+      print $0
+    }
+  }
+
+  # [PRINT] Multiline "default" statement
+  if (blockCnt > 0 && blockDefCnt > 0) {
+    if (blockDefStart == 1) {
+      blockDefStart = 0
+    } else {
+      print $0
+    }
+  }
+}
+EOF
+
+}
+
 getopt() {
   # pure-getopt, a drop-in replacement for GNU getopt in pure Bash.
   # version 1.4.3