post-receive

#!/bin/bash

### Instana GitOps Hook: This post-receive Git hook script will trigger an update of configurations of
### Instana host agents configured with the Git-based configuration management.
###
### Installation:
###
### 1. Copy this file into the folder `.git/hooks` in your Git repository
### 2. Create a `.git/instana-backend` file, with the following structure:
###
### INSTANA_API_ENDPOINT=<required: endpoint of your tenant unit, e.g., https://prod-mycompany.instana.io>
### INSTANA_API_TOKEN=<required: valid API token with the `Configuration of agents` permission>
### INSTANA_AGENT_ZONE=<agent zone to match; all agents in this zone that are configured to use Git, will update their configs>
### INSTANA_AGENT_TAGS=<agents tags to match; all agents that have all these tags and that are configured to use Git, will update their configs>
###
### # Either INSTANA_AGENT_ZONE or INSTANA_AGENT_TAGS must be set
###
### For more info on the Git-based configuration management for Instana host agents, refer to
### https://www.instana.com/docs/setup_and_manage/host_agent/configuration/git_ops documentation.
### For more info on Git Hooks, https://git-scm.com/docs/githooks is an excellent place to start.

if [ -f "${GIT_DIR}/instana-backend" ]; then
    source "${GIT_DIR}/instana-backend"
fi

if [ -z "${INSTANA_API_ENDPOINT}" ]; then
    echo "GitOps update request failed: The required 'INSTANA_API_ENDPOINT' variable is not set in the post-receive hook"
    exit 0
fi

if [ -z "${INSTANA_API_TOKEN}" ]; then
    echo "GitOps update request failed: The required 'INSTANA_API_TOKEN' variable is not set in the post-receive hook"
    exit 0
fi

if [ -n "${INSTANA_AGENT_ZONE}" ]; then
    query="entity.zone:\"${INSTANA_AGENT_ZONE}\""
fi

if [ -n "${INSTANA_AGENT_TAGS}" ]; then
    IFS=',' read -r -a tags <<< "${INSTANA_AGENT_TAGS}"

    for tag in "${tags[@]}"
    do
        if [ -n "${query}" ]; then
            query="${query} AND entity.tag:\"${tag}\""
        else 
            query="entity.tag:\"${tag}\""
        fi
    done
fi

if [ -z "${query}" ]; then
    echo "GitOps update request failed: Neither the 'INSTANA_AGENT_ZONE' nor 'INSTANA_AGENT_TAGS' variables have been configured in the post-receive hook"
    exit 0;
fi

echo -n "GitOps update: Triggering the configuration update of agents matching the following query: '${query}' ... "

if RESPONSE=$(curl \
    --location \
    --silent \
    --fail \
    --request POST \
    --header "authorization: apiToken ${INSTANA_API_TOKEN}" \
    --write-out "%{http_code}" \
    "${INSTANA_API_ENDPOINT}/api/host-agent/configuration?query=${query// /%20}")
then
    echo "OK"
else
    echo "FAILED: The configuration update call to the Instana backend API failed with status code ${RESPONSE}"
fi