ENH: option to dynamically set the AMS net id at runtime

.github/pull_request_template.md

@@ -21,6 +21,7 @@
 
 ## Pre-merge checklist
 - [ ] Code works interactively
+- [ ] Code works interactively in dry_run mode
 - [ ] Code contains descriptive docstrings, including context and API
 - [ ] Pre-commit passes on GitHub Actions
 - [ ] Documentation under https://confluence.slac.stanford.edu/display/PCDS/TcBSD has been updated appropriately

group_vars/tcbsd_plcs/vars.yml

@@ -11,6 +11,11 @@ enable_freebsd_packages: false
 use_psproxy: true
 use_psntp: true
 
+# Dynamic AMS net id = set AMS net id to ip addr .1.1
+# Static AMS net id = set AMS net id to the value of tc_ams_net_id
+dynamic_ams: true
+# tc_ams_net_id: 0.0.0.0.1.1
+
 # set static IP on x000 (mac id 2)
 x000_set_static_ip: true
 x000_static_ip: 192.168.1.10

group_vars/tcbsd_vms/vars.yml

@@ -12,6 +12,10 @@ enable_freebsd_packages: false
 use_psproxy: false
 use_psntp: false
 
+# Dynamic AMS net id = set AMS net id to ip addr .1.1
+# Static AMS net id = set AMS net id to the value of tc_ams_net_id
+dynamic_ams: false
+
 # set static IP on x000 (mac id 2)
 x000_set_static_ip: false
 x000_static_ip: 192.168.1.10

host_vars/plc-tmo-tmp-vac/vars.yml

@@ -1,6 +1,5 @@
 ---
 ansible_host: plc-tmo-tmp-vac
-tc_ams_net_id: 172.21.132.78.1.1
 
 # Uncomment any setting below and change it to override a default setting.
 #ansible_user: Administrator
@@ -15,6 +14,11 @@ tc_ams_net_id: 172.21.132.78.1.1
 #use_psproxy: true
 #use_psntp: true
 #
+## Dynamic AMS net id = set AMS net id to ip addr .1.1
+## Static AMS net id = set AMS net id to the value of tc_ams_net_id
+#dynamic_ams: true
+## tc_ams_net_id: 0.0.0.0.1.1
+#
 ## set static IP on x000 (mac id 2)
 #x000_set_static_ip: true
 #x000_static_ip: 192.168.1.10

host_vars/plc-tst-bsd1/vars.yml

@@ -1,6 +1,5 @@
 ---
 ansible_host: plc-tst-bsd1
-tc_ams_net_id: 172.21.148.81.1.1
 
 # Uncomment any setting below and change it to override a default setting.
 #ansible_user: Administrator
@@ -15,6 +14,11 @@ tc_ams_net_id: 172.21.148.81.1.1
 #use_psproxy: true
 #use_psntp: true
 #
+## Dynamic AMS net id = set AMS net id to ip addr .1.1
+## Static AMS net id = set AMS net id to the value of tc_ams_net_id
+#dynamic_ams: true
+## tc_ams_net_id: 0.0.0.0.1.1
+#
 ## set static IP on x000 (mac id 2)
 #x000_set_static_ip: true
 #x000_static_ip: 192.168.1.10

host_vars/plc-tst-bsd2/vars.yml

@@ -1,6 +1,5 @@
 ---
 ansible_host: plc-tst-bsd2
-tc_ams_net_id: 172.21.148.94.1.1
 
 # Uncomment any setting below and change it to override a default setting.
 #ansible_user: Administrator
@@ -15,6 +14,11 @@ tc_ams_net_id: 172.21.148.94.1.1
 #use_psproxy: true
 #use_psntp: true
 #
+## Dynamic AMS net id = set AMS net id to ip addr .1.1
+## Static AMS net id = set AMS net id to the value of tc_ams_net_id
+#dynamic_ams: true
+## tc_ams_net_id: 0.0.0.0.1.1
+#
 ## set static IP on x000 (mac id 2)
 #x000_set_static_ip: true
 #x000_static_ip: 192.168.1.10

ip_macros.j2

@@ -1,5 +1,5 @@
 {%- macro ip_to_ams_net_id(hostname) -%}
-{%- set ipaddr = lookup('dig', hostname) -%}
+{%- set ipaddr = lookup('community.general.dig', hostname, fail_on_error=True) -%}
 {{ ipaddr }}.1.1
 {%- endmacro -%}
 

scripts/make_vars.py

@@ -10,7 +10,6 @@
 import socket
 from typing import Iterator
 from pathlib import Path
-from string import Template
 
 from ruamel.yaml import YAML
 
@@ -65,26 +64,36 @@ def get_netid(hostname: str) -> str:
     return ipaddr + ".1.1"
 
 
+def tcbsd_vms_extra_vars(
+    hostname: str,
+) -> dict[str, str]:
+    """
+    Assign a starting ams net id for the tcbsd vms.
+
+    The IPs for these can be less stable than for CDS PLCs,
+    so don't dynamically update it every run.
+    """
+    return {"tc_ams_net_id": get_netid(hostname)}
+
+
 def write_host_vars(
     hostname: str,
     host_vars_path: str | Path,
     group_vars_path: str | Path,
-    template_path: str | Path,
+    extra_vars: dict[str, str] | None = None,
 ) -> None:
     """Write the vars.yml file given the necessary information."""
-    # Load the template, sub in the values
-    with Path(template_path).open("r") as fd:
-        template = Template(fd.read())
-    host_vars_text = template.substitute(
-        PLC_IP=hostname,
-        PLC_NET_ID=get_netid(hostname=hostname),
-    )
+    if extra_vars is None:
+        extra_vars = {}
     # Load the group vars, prepend with comment
     with Path(group_vars_path).open("r") as fd:
         group_vars_lines = ["#" + line for line in fd.read().splitlines()[1:]]
     # Write the new file
     with Path(host_vars_path).open("w") as fd:
-        fd.write(host_vars_text)
+        fd.write("---\n")
+        fd.write(f"ansible_host: {hostname}\n")
+        for key, value in extra_vars.items():
+            fd.write(f"{key}: {value}")
         fd.write(
             "\n"
             "# Uncomment any setting below and change it "
@@ -104,15 +113,18 @@ def main(hostname: str) -> int:
         inventory_path=inventory_path,
         groups_path=groups_path,
     )
+    if group == "tcbsd_vms":
+        extra_vars = tcbsd_vms_extra_vars(hostname)
+    else:
+        extra_vars = {}
     group_vars_path = groups_path / group / "vars.yml"
-    template_path = repo_root / "tcbsd-plc.yaml.template"
     host_vars_path = repo_root / "host_vars" / hostname / "vars.yml"
     host_vars_path.parent.mkdir(exist_ok=True)
     write_host_vars(
         hostname=hostname,
         host_vars_path=host_vars_path,
         group_vars_path=group_vars_path,
-        template_path=template_path,
+        extra_vars=extra_vars,
     )
     print(
         f"Created {host_vars_path}, "

tcbsd-provision-playbook.yaml

@@ -12,6 +12,7 @@
         cmd: TcSysExe.exe --mode
 
     - name: Assert that PLC is in CONFIG mode
+      when: not ansible_check_mode
       ansible.builtin.assert:
         that: "{{ 'CONFIG' in plc_mode.stdout }}"
         fail_msg: "PLC is in RUN mode! Abort!"
@@ -155,7 +156,12 @@
       community.general.xml:
         path: /usr/local/etc/TwinCAT/3.1/TcRegistry.xml
         xpath: /TcRegistry/Key[@Name='HKLM']/Key[@Name='Software']/Key[@Name='Beckhoff']/Key[@Name='TwinCAT3']/Key[@Name='System']/Value[@Name='AmsNetId']
-        value: "{% import 'ip_macros.j2' as ip_macros %}{{ ip_macros.ams_net_id_to_binary(tc_ams_net_id) }}"
+        value: >-
+          {%- import 'ip_macros.j2' as ip_macros -%}
+          {%- if dynamic_ams -%}
+          {%- set tc_ams_net_id = ip_macros.ip_to_ams_net_id(ansible_host) -%}
+          {%- endif -%}
+          {{ ip_macros.ams_net_id_to_binary(tc_ams_net_id) }}
       register: ams_net_id
 
     - name: Adjust the locked memory size