Creating and exposing /credentials as a volume in the container

Author: haggaret

Dockerfile

@@ -2,10 +2,14 @@ FROM jfloff/alpine-python:2.7-slim
 
 MAINTAINER Signiant DevOps <devops@signiant.com>
 
+RUN mkdir -p /credentials
+
 ADD parameter_sync.py /parameter_sync.py
 ADD parameter_sync.sh /parameter_sync.sh
 
 RUN pip install boto3
 RUN chmod a+x /parameter_sync.py /parameter_sync.sh
 
+VOLUME /credentials
+
 ENTRYPOINT ["/parameter_sync.sh"]

README.md

@@ -10,13 +10,13 @@ Keep file contents in sync with matching parameters in AWS Parameter Store
 - AWS_REGION - AWS Region to search (defaults to us-east-1)
 - PARAM_PREFIX - The prefix for the parameters to keep in sync
     - resulting filenames will be the parameter name minus the PARAM_PREFIX
-    - eg.
-      Following parameters in parameter store: TESTING_param1.txt, TESTING_param2.conf
-      export PARAM_PREFIX=TESTING_
-      TESTING_param1.txt will be compared against param1.txt
-      TESTING_param2.conf will be compared against param2.conf
-- CRED_FOLDER_PATH - path to where files are stored (defaults to /credentials)
-    - in order to access the files outside of the container, make sure to mount this path into the container
+    - eg. Following parameters in parameter store: TESTING_param1.txt, TESTING_param2.conf
+        - export PARAM_PREFIX=TESTING_
+        - TESTING_param1.txt will be compared against param1.txt
+        - TESTING_param2.conf will be compared against param2.conf
+
+The docker container exposes /credentials as a volume - this can be shared with other
+containers or mounted to the local file system
 
 
 ## Example Docker runs
@@ -30,29 +30,28 @@ folder 'credentials-dir' which is mounted into the container at '/credentials'.
 
 ````
 docker run -d -e "FREQUENCY=600" \
-        -e "VERBOSE=1" \
-        -e "AWS_ACCESS_KEY_ID=MY_ACCESS_KEY_ID \
-        -e "AWS_SECRET_ACCESS_KEY=MY_SECRET_KEY \
-        -e "PARAM_PREFIX=TESTING_" \
-        -v credentials-dir:/credentials \
-        signiant/aws-parameter-syncer
+ -e "VERBOSE=1" \
+ -e "AWS_ACCESS_KEY_ID=MY_ACCESS_KEY_ID \
+ -e "AWS_SECRET_ACCESS_KEY=MY_SECRET_KEY \
+ -e "PARAM_PREFIX=TESTING_" \
+ -v credentials-dir:/credentials \
+ signiant/aws-parameter-syncer
 ````
 
 This example checks AWS Parameter Store in the us-west-2 region every 120 seconds (2 minutes)
 for parameters containing 'TESTING_'. The credentials in AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY are
-used to access the AWS Parameter Store. The parameter values will be checked against files in the local
-folder '/my/local/credentials/path' which is mounted into the container at '/some/other/path'.
+used to access the AWS Parameter Store. The parameter values will be checked against files in the container
+volume '/credentials' which is NOT mounted locally. This volume could be shared with other containers if
+desired.
 
 
 ````
 docker run -d -e "FREQUENCY=120" \
-        -e "AWS_ACCESS_KEY_ID=MY_ACCESS_KEY_ID \
-        -e "AWS_SECRET_ACCESS_KEY=MY_SECRET_KEY \
-        -e "AWS_REGION=us-west-2"
-        -e "PARAM_PREFIX=TESTING_" \
-        -e "CRED_FOLDER_PATH=/some/other/path"
-        -v /my/local/credentials/path:/some/other/path \
-        signiant/aws-parameter-syncer
+ -e "AWS_ACCESS_KEY_ID=MY_ACCESS_KEY_ID \
+ -e "AWS_SECRET_ACCESS_KEY=MY_SECRET_KEY \
+ -e "AWS_REGION=us-west-2"
+ -e "PARAM_PREFIX=TESTING_" \
+ signiant/aws-parameter-syncer
 ````
 
 

parameter_sync.sh

@@ -6,6 +6,8 @@ if [ "$VERBOSE" ]; then
     VERBOSE='--verbose'
 fi
 
+CRED_FOLDER_PATH=/credentials
+
 # Check for required ENV Variables
 if [ -z "$PARAM_PREFIX" ]; then
     echo "Must supply a parameter prefix by setting the PARAM_PREFIX environment variable"
@@ -37,21 +39,6 @@ else
     echo "Frequency set to $FREQUENCY seconds"
 fi
 
-if [ -z "$CRED_FOLDER_PATH" ]; then
-    CRED_FOLDER_PATH=/credentials
-    echo "CRED_FOLDER_PATH environment variable missing - assuming default of ${CRED_FOLDER_PATH}"
-fi
-
-if [ ! -e "$CRED_FOLDER_PATH" ]; then
-    echo "${CRED_FOLDER_PATH} doesn't exist, will attempt to create it"
-    echo "NOTE: If this was not expected - please mount credentials path at ${CRED_FOLDER_PATH}"
-    mkdir -p ${CRED_FOLDER_PATH}
-    if [ "$?" -ne 0 ]; then
-        echo "Unable to create ${CRED_FOLDER_PATH} - exiting..."
-        exit 1
-    fi
-fi
-
 # Loop forever, sleeping for our frequency
 while true
 do