terraformscaffold v1.1.4 - Global and Region scoped variables files

Author: Zordrak

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.1.4 (16/05/2017)
+
+ * Global and Region scoped variables files
+
 ## 1.1.3 (12/04/2017)
 
  * Support the use of .terraform-version file in components when in the presence of [tfenv](https://github.com/kamatama41/tfenv)

README.md

@@ -31,7 +31,15 @@ Scaffold uses AWS S3 for storage of tfstate files. The bucket and location are s
 
 ### Variables Files: Environment & Versions
 
-Scaffold provides a logical separation of two types of environment variable. Standard static variables and frequently-changing versions variables. This seperation is purely logical, not functional. It makes no functional difference in which file a variable lives, or even whether a versions variables file exists; but it provides the capacity to seperate out mostly static variables that define the construction of the environment from variables that could change on each apply providing new AMI IDs, or dockerised application versions or database snapshot IDs when recreating development and testing databases.
+Scaffold provides a logical separation of several types of environment variable:
+ * Global variables
+ * Region-scoped global variables
+ * Static environment variables
+ * Frequently-changing versions variables
+ * Dynamic (S3 stored) variables
+ * Secret (S3 stored, KMS encrypted variables - available but not recommended)
+
+This seperation is purely logical, not functional. It makes no functional difference in which file a variable lives, or even whether a versions variables file exists; but it provides the capacity to seperate out mostly static variables that define the construction of the environment from variables that could change on each apply providing new AMI IDs, or dockerised application versions or database snapshot IDs when recreating development and testing databases.
 
 ### AWS Credentials
 

bin/terraform.sh

@@ -8,7 +8,7 @@
 ##
 # Set Script Version
 ##
-readonly script_ver="1.1.3";
+readonly script_ver="1.1.4";
 
 ##
 # Standardised failure function
@@ -363,11 +363,29 @@ if [ ! -f "${env_file_path}" ]; then
   error_and_die "Unknown environment. ${env_file_path} does not exist.";
 fi;
 
+# Check for presence of a global variables file, and use it if readable
+readonly global_vars_file_name="global.tfvars";
+readonly global_vars_file_path="${base_path}/etc/${global_vars_file_name}";
+
+# Check for presence of a region variables file, and use it if readable
+readonly region_vars_file_name="${region}.tfvars";
+readonly region_vars_file_path="${base_path}/etc/${region_vars_file_name}";
+
 # Collect the paths of the variables files to use
 declare tf_var_files;
 declare -a tf_var_file_paths;
 
-tf_var_file_paths=("${env_file_path}");
+# Use Global and Region first, to allow potential for terraform to do the
+# honourable thing and override global and region settings with environment
+# specific ones; however we do not officially support the same variable
+# being declared in multiple locations, and we warn when we find any duplicates
+[ -f "${global_vars_file_path}" ] && tf_var_file_paths+=("${global_vars_file_path}");
+[ -f "${region_vars_file_path}" ] && tf_var_file_paths+=("${region_vars_file_path}");
+
+# We've already checked this is readable and its presence is mandatory
+tf_var_file_paths+=("${env_file_path}");
+
+# If present and readable, use versions and dynamic variables too
 [ -f "${versions_file_path}" ] && tf_var_file_paths+=("${versions_file_path}");
 [ -f "${dynamic_file_path}" ] && tf_var_file_paths+=("${dynamic_file_path}");
 
@@ -379,9 +397,16 @@ duplicate_variables="$(cat "${tf_var_file_paths[@]}" | sed -n -e 's/\(^[a-zA-Z0-
 # WARNING #
 ###########
 The following input variables appear to be duplicated:
+
 ${duplicate_variables}
 
-This could lead to unexpected behaviour.
+This could lead to unexpected behaviour. Overriding of variables has
+previously been unpredictable and is not currently supported, but it
+may work.
+
+Recent changes to terraform might give you useful overriding and
+map-merging functionality, please use with caution and report back
+on your successes & failures.
 ###########";
 
 # Build up the tfvars arguments for terraform command line

etc/env_eg-region-1_exampleenv.tfvars

@@ -0,0 +1,10 @@
+# Define variable values to be fed into components in the components directory that will each form a part of the examplenv environment...
+
+environment = "exampleenv"
+
+default_tags = {
+  "Project"     = "myproject"
+  "Environment" = "exampleenv"
+  "Owner"       = "My Project Manager"
+  "Client"      = "My Client"
+}

etc/env_eu-west-1_exampleenv.tfvars

@@ -0,0 +1,3 @@
+# Specific to region within project/AWS Account
+terraform_state_bucket = "myproject-terraformscaffold-012345678901-eu-west-1"
+region                 = "eu-west-1"

etc/eu-west-1.tfvars

@@ -0,0 +1,3 @@
+# Specific to whole project / AWS Account
+project        = "myproject"
+aws_account_id = "012345678901"

etc/global.tfvars

@@ -1 +1,2 @@
 # Define variable values to be fed into components in the components directory that will each form a part of the examplenv environment...
+my_example_docker_app_version="0.0.1"